Preparation and application of ethylene propylene diene monomer material and coated rubber sealing ring

Abstract

The invention belongs to the technical field of fuel cabin sealing, and particularly relates to preparation and application of an ethylene propylene diene monomer material and a coated rubber sealing ring. The ethylene propylene diene monomer material is prepared from the following raw materials in parts by weight: 20 to 70 parts of raw ethylene propylene diene monomer, 5 to 10 parts of tackifying resin, 30 to 45 parts of wear-resistant filler, 1 to 7 parts of plasticizer, 0.1 to 5 parts of anti-aging agent, 0.5 to 3 parts of vulcanizing agent and 0.1 to 3 parts of vulcanization accelerator, wherein the total weight part of the raw materials is 100 parts; the wear-resistant filler comprises carbon black and nano magnesium oxide, and the mass ratio of the carbon black to the nano magnesium oxide is (5: 1)-(20: 1). The carbon black and the nano magnesium oxide are used as wear-resistant filling agents, so that the strength and the wear resistance of the ethylene propylene diene monomer material are improved; meanwhile, the mechanical strength and the chemical corrosion resistance of the ethylene propylene diene monomer material can be remarkably improved by jointly adding the carbon black and the nano magnesium oxide.

Description

Technical Field

[0001] The invention relates to the technical field of fuel tank sealing, and in particular to the preparation and application of an EPDM rubber material and a coated rubber sealing ring. Background Art

[0002] High-speed underwater power machinery relies on the chemical combustion of reactive fuel to provide kinetic energy for underwater vehicles. The reactive fuel supply tank is the main device for storing and supplying fuel. In order to effectively ensure reliable sealing and no leakage during the static storage of the fuel supply tank, stable and reliable sealed storage is of great significance to ensure the long-term stability of the fuel. Underwater power machinery uses special chemical fuels, mainly OTTO-Ⅱ combustion agent composed of a mixture of 1,2-propylene glycol dinitroester, 2-nitrodiphenylamine and dibutyl sebacic acid, and hydroxylamine perchlorate (HAP) as a reducing agent. HAP has strong chemical corrosion properties. The sealing ring formed by natural rubber and traditional synthetic rubber will be chemically corroded when immersed in such fuel for a long time, which causes the sealing ring to swell, chemically decompose, etc., resulting in reduced elasticity and inability to play an effective sealing role. That is, the existing sealing ring has poor chemical corrosion resistance. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide an EPDM rubber material and the preparation and application of a coated rubber sealing ring. The EPDM rubber material provided by the present invention has excellent chemical corrosion resistance.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides an EPDM rubber material. Taking the total weight of the raw materials as 100 parts, the EPDM rubber material includes the following raw materials in parts by weight:

[0006] 20-70 parts of EPDM raw rubber, 5-10 parts of tackifying resin, 30-45 parts of wear-resistant filler, 1-7 parts of plasticizer, 0.1-5 parts of anti-aging agent, 0.5-3 parts of vulcanizing agent, and 0.1-3 parts of vulcanization accelerator;

[0007] The wear-resistant filler comprises carbon black and nano magnesium oxide, and the mass ratio of the carbon black to the nano magnesium oxide is 5:1 to 20:1.

[0008] Preferably, the carbon black includes carbon black N774, carbon black N990 and carbon black N330, and the mass ratio of the carbon black N774, carbon black N990 and carbon black N330 is 2:2:1.

[0009] Preferably, the tackifying resin is an alkylphenol-formaldehyde resin, and the molecular weight of the alkylphenol-formaldehyde resin is 500-700 and the softening point is 120-140°C.

[0010] Preferably, the Mooney viscosity of the EPDM raw rubber is 50-80, the ethylene content is 30-60%, and the third monomer content is 4-10%;

[0011] The plasticizer is stearic acid;

[0012] The anti-aging agent comprises dicumyl peroxide (DCP) and triallyl isocyanurate, and the mass of the dicumyl peroxide (DCP) is not less than 70% of the total mass of the dicumyl peroxide (DCP) and triallyl isocyanurate;

[0013] The vulcanizing agent is sulfur;

[0014] The vulcanization accelerator comprises dibenzothiazole disulfide (DM) and dimethyl bisthiocarbonyl disulfide (TMTD), wherein the mass ratio of dibenzothiazole disulfide to dimethyl bisthiocarbonyl disulfide is 1:1.

[0015] The present invention also provides a method for preparing the EPDM rubber material described in the above technical solution, comprising the following steps:

[0016] The prepared raw materials are sequentially mixed, shaped and hot-pressed to obtain the EPDM rubber material.

[0017] The present invention also provides a coated rubber sealing ring, comprising an EPDM rubber ring and a fluoroplastic film coating the EPDM rubber ring; the EPDM rubber ring and the fluoroplastic film are bonded by an adhesive; the EPDM rubber ring is made of the EPDM rubber material described in the above technical solution or the EPDM rubber material prepared by the preparation method described in the above technical solution.

[0018] Preferably, the material of the fluoroplastic film includes polytetrafluoroethylene (PTFE), fusible polytetrafluoroethylene (PFA) or ethylene-tetrafluoroethylene copolymer (FEP), and the thickness of the fluoroplastic film is 0.005-0.05 mm;

[0019] The adhesive is an epoxy resin adhesive.

[0020] The present invention also provides a method for preparing the coated rubber sealing ring described in the above technical solution, comprising the following steps:

[0021] Provide EPDM rubber ring;

[0022] After the adhesive is coated on the surface of the EPDM rubber ring and dried, a fluoroplastic film is brought into contact with the adhesive and covers the EPDM rubber ring. The formed assembly is subjected to hot pressing and vulcanization molding to obtain the coated rubber sealing ring.

[0023] Preferably, before the fluoroplastic film is coated, the method further comprises: treating the coated surface of the fluoroplastic film with a sodium naphthalene solution, and then performing pre-forming;

[0024] The temperature of the hot pressing vulcanization molding is 150-60° C., the pressure is 5-10 MPa, and the time is 20-40 minutes.

[0025] The present invention also provides the use of the EPDM rubber material described in the above technical solution, the EPDM rubber material obtained by the preparation method, the coated rubber sealing ring, or the coated rubber sealing ring obtained by the preparation method in fuel tank sealing.

[0026] The invention provides an EPDM rubber material.

[0027] The EPDM rubber material of the invention uses carbon black and nano magnesium oxide as wear-resistant fillers, thereby improving the strength and wear resistance of the EPDM rubber material; meanwhile, the co-addition of carbon black and nano magnesium oxide can significantly improve the permanent compression deformation and solvent resistance of the EPDM rubber material.

[0028] Furthermore, by adding tackifying resin alkylphenol-formaldehyde resin into the EPDM rubber material, the adhesion between the EPDM rubber material and the fluoroplastic film is improved.

[0029] The present invention also provides a coated rubber sealing ring. The coated rubber sealing ring of the present invention combines an EPDM rubber material with good solvent resistance and a fluoroplastic film, which can effectively isolate the coated rubber sealing ring from direct contact with hydroxylamine perchlorate fuel, so that the coated rubber sealing ring has excellent solvent resistance and does not affect the elastic compensation function of the coated rubber sealing ring.

[0030] The present invention also provides a method for preparing the coated rubber sealing ring described in the above technical solution. The present invention treats the fluoroplastic film with a sodium naphthalene solution, thereby further improving the bonding force between the fluoroplastic film and the EPDM rubber ring. The coated rubber sealing ring prepared by the present invention has a smooth surface without wrinkles, no pores inside, and no obvious weld line at the joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of a pre-molding mold;

[0032] Figure 2 A schematic diagram of a fluoroplastic film having a predetermined structure;

[0033] Figure 3 A schematic diagram of the assembly;

[0034] Figure 4 Schematic diagram of the mold for forming the encapsulated sealing ring. DETAILED DESCRIPTION

[0035] The present invention provides an EPDM rubber material. Taking the total weight of the raw materials as 100 parts, the EPDM rubber material includes the following raw materials in parts by weight:

[0036] 20-70 parts of EPDM raw rubber, 5-10 parts of tackifying resin, 30-45 parts of wear-resistant filler, 1-7 parts of plasticizer, 0.1-5 parts of anti-aging agent, 0.5-3 parts of vulcanizing agent, and 0.1-3 parts of vulcanization accelerator;

[0037] The wear-resistant filler comprises carbon black and nano magnesium oxide, and the mass ratio of the carbon black to the nano magnesium oxide is 5:1 to 20:1.

[0038] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0039] Based on 100 parts by weight of the total raw materials, the raw materials for preparing the EPDM rubber ring provided by the present invention include 20 to 70 parts by weight of EPDM raw rubber (EPR), and are preferably 20, 30, 32, 40, 47, 50, 57, 60 or 70 parts by weight. In the present invention, the Mooney viscosity of the EPDM raw rubber is preferably 50 to 80, and is preferably 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 or 80; the ethylene content is preferably 30 to 60%, and is preferably 30%, 35%, 40%, 45%, 48%, 50%, 55% or 60%; the third monomer content is preferably 4 to 10%, and is preferably 4%, 5%, 6%, 7%, 8%, 9% or 10%. In a specific embodiment of the present invention, the EPDM raw rubber is preferably purchased from Alantai Rubber (Nantong) Chemical Industry Co., Ltd., with a Mooney viscosity of 65, an ethylene content of 48%, and a third monomer content of 9%.

[0040] Based on 100 parts by weight of the total raw materials, the raw materials for preparing the EPDM rubber ring provided by the present invention include 5 to 10 parts by weight of tackifying resin, and are preferably 5, 6, 7, 8, 9 or 10 parts by weight. In the present invention, the tackifying resin is preferably an alkylphenol-formaldehyde resin, and the molecular weight of the alkylphenol-formaldehyde resin is preferably 500 to 700, and is preferably 500, 550, 600, 650 or 700; the softening point is preferably 120 to 140°C, and is preferably 120°C, 125°C, 130°C, 135°C or 140°C. In a specific embodiment of the present invention, the alkylphenol-formaldehyde resin is preferably purchased from Arakawa Chemical Co., Ltd. of Japan, and has a molecular weight of 550 and a softening point of 130°C. In the present invention, the alkylphenol-formaldehyde resin can increase the activity of EPDM rubber and improve its adhesion to fluoroplastic film.

[0041] Based on 100 parts by weight of the total raw materials, the raw materials for preparing the EPDM rubber ring provided by the present invention include 30 to 45 parts by weight of wear-resistant filler, and are preferably 30 parts by weight, 35 parts by weight, 40 parts by weight or 45 parts by weight. In the present invention, the wear-resistant filler includes carbon black and nano magnesium oxide, and the mass ratio of the carbon black to the nano magnesium oxide is 5:1 to 20:1, preferably 5:1 to 10:1, and is preferably 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1 or 20:1. In the present invention, the particle size of the nano magnesium oxide is preferably 20 to 80 nm. In the present invention, the carbon black preferably includes carbon black N774, carbon black N990 and carbon black N330, and the mass ratio of the carbon black N774, carbon black N990 and carbon black N330 is preferably 2:2:1. In the present invention, the wear-resistant filler can significantly improve the strength and wear resistance of the EPDM rubber, and the co-addition of carbon black and nano magnesium oxide can significantly improve the mechanical strength and chemical corrosion resistance of the EPDM rubber.

[0042] The raw materials for preparing the EPDM rubber ring provided by the present invention include 1 to 7 parts by weight of a plasticizer, preferably 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight or 7 parts by weight, based on 100 parts by weight of the total raw materials. In the present invention, the plasticizer is preferably stearic acid. In the present invention, the plasticizer can improve the plasticity of the EPDM rubber during the mixing process and the fluidity during the vulcanization process.

[0043] Based on 100 parts by weight of the total raw materials, the raw materials for preparing the EPDM rubber ring provided by the present invention include 0.1 to 5 parts by weight of an anti-aging agent, and are preferably 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5 parts by weight. In the present invention, the anti-aging agent preferably includes dicumyl peroxide (DCP) and triallyl isocyanurate, and the mass of the dicumyl peroxide (DCP) is preferably not less than 70% of the total mass of dicumyl peroxide (DCP) and triallyl isocyanurate, and is further preferably 70 to 95%, and is preferably 70%, 75%, 80%, 85%, 90% or 95%.

[0044] Based on 100 parts by weight of the total raw materials, the raw materials for preparing the EPDM rubber ring provided by the present invention include 0.5 to 3 parts by weight of a vulcanizing agent, and specifically preferably 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight or 3 parts by weight. In the present invention, the vulcanizing agent is preferably sulfur. In the present invention, the particle size of the sulfur is preferably 10 to 30 μm.

[0045] Based on 100 parts by weight of the total raw materials, the raw materials for preparing the EPDM rubber ring provided by the present invention include 0.1 to 3 parts by weight of a vulcanization accelerator, and specifically preferably 0.1 parts by weight, 0.5 parts by weight, 1 parts by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight or 3 parts by weight. In the present invention, the vulcanization accelerator preferably includes dibenzothiazole disulfide (DM) and dimethyl bisthiocarbonyl disulfide (TMTD), and the mass ratio of dibenzothiazole disulfide to dimethyl bisthiocarbonyl disulfide is preferably 1:1.

[0046] The present invention also provides a method for preparing the EPDM rubber material described in the above technical solution, comprising the following steps:

[0047] The prepared raw materials are sequentially mixed, shaped and hot-pressed to obtain the EPDM rubber material.

[0048] In the present invention, the mixing is preferably carried out in an open mill. In the present invention, the mixing temperature is preferably 60 to 90°C, specifically preferably 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C; the rotation speed is preferably 20 to 50 rpm, specifically preferably 20 rpm, 25 rpm, 30 rpm, 35 rpm, 40 rpm, 45 rpm or 50 rpm; the time is preferably 30 to 50 min, specifically preferably 30 min, 35 min, 40 min, 45 min or 50 min.

[0049] In the present invention, the temperature of the shaping treatment is preferably 80-100°C, specifically preferably 80°C, 85°C, 90°C, 95°C or 100°C; the pressure is preferably 2-8MPa, specifically preferably 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa or 8MPa; the time is preferably 2-10min, specifically preferably 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min or 10min. In the present invention, the shaping treatment is preferably carried out in a shaping mold. In the present invention, the material of the shaping mold is preferably steel. The present invention does not specifically limit the shape of the shaping mold, and those skilled in the art can set it according to actual needs.

[0050] In the present invention, the temperature of the hot pressing molding is preferably 100-140°C, and is particularly preferably 100°C, 110°C, 120°C, 130°C or 140°C; the pressure is preferably 3-10MPa, and is particularly preferably 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa or 10MPa; the time is preferably 1-3min, and is particularly preferably 1min, 2min or 3min. In the present invention, the hot pressing molding is preferably carried out on a flat vulcanizer.

[0051] The present invention also provides a coated rubber sealing ring, comprising an EPDM rubber ring and a fluoroplastic film coating the EPDM rubber ring; the EPDM rubber ring and the fluoroplastic film are bonded by an adhesive.

[0052] The EPDM rubber ring is made of the EPDM rubber material described in the above technical solution or the EPDM rubber material prepared by the preparation method described in the above technical solution.

[0053] The coated rubber sealing ring provided by the present invention comprises an EPDM rubber ring; the EPDM rubber ring is made of the EPDM rubber material described in the above technical solution or the EPDM rubber material prepared by the preparation method described in the above technical solution.

[0054] The coated rubber sealing ring provided by the present invention comprises a fluoroplastic film coating the EPDM rubber ring, and the material of the fluoroplastic film preferably comprises polytetrafluoroethylene (PTFE), fusible polytetrafluoroethylene (PFA) or ethylene-tetrafluoroethylene copolymer (FEP), and is further preferably polytetrafluoroethylene (PTFE). In the present invention, the polytetrafluoroethylene (PTFE) film is preferably an amorphous film. In the present invention, the fusible polytetrafluoroethylene (PFA) and ethylene-tetrafluoroethylene copolymer (FEP) films are preferably extruded films or blown films.

[0055] In the present invention, the thickness of the fluoroplastic film is preferably 0.005-0.05 mm, and more preferably 0.01 mm or 0.02 mm.

[0056] The coated rubber sealing ring provided by the present invention comprises an adhesive, and the adhesive is used to bond the EPDM rubber ring and the fluoroplastic film. In the present invention, the adhesive is preferably an epoxy resin adhesive.

[0057] In the present invention, the coated rubber sealing ring is preferably an O-ring.

[0058] The present invention also provides a method for preparing the coated rubber sealing ring described in the above technical solution, comprising the following steps:

[0059] Provide EPDM rubber ring;

[0060] After the adhesive is coated on the surface of the EPDM rubber ring and dried, a fluoroplastic film is brought into contact with the adhesive and covers the EPDM rubber ring, and hot pressing and vulcanization molding is performed to obtain the coated rubber sealing ring.

[0061] The present invention provides an EPDM rubber ring. In the present invention, the preparation method of the EPDM rubber ring is preferably consistent with the preparation method of the EPDM rubber material described in the above technical solution, and specifically preferably includes: preparing raw materials and performing mixing, shaping and hot pressing in sequence to obtain the EPDM rubber ring. In the present invention, the mixing and hot pressing are preferably consistent with the above technical solution, which will not be repeated here. In the present invention, the shape of the shaping mold is preferably capable of forming an EPDM rubber ring.

[0062] After obtaining the EPDM rubber ring, the present invention applies adhesive on the surface of the EPDM rubber ring and allows the surface to dry, then brings the fluoroplastic film into contact with the adhesive and covers the EPDM rubber ring, and performs hot pressing and vulcanization molding on the formed assembly to obtain the coated rubber sealing ring.

[0063] In the present invention, the coating amount of the adhesive is preferably 0.1 to 2.0 mg / cm 2 , preferably 0.1 mg / cm 2 , 0.15mg / cm 2 , 0.5mg / cm 2 , 1mg / cm 2 , 1.5mg / cm 2 or 2mg / cm 2 .

[0064] Before the fluoroplastic film is coated, the present invention preferably further comprises: treating the coated surface of the fluoroplastic film with a sodium naphthalene solution, and then performing pre-molding. In the present invention, the coated surface of the fluoroplastic film refers to the side of the fluoroplastic film that contacts the EPDM rubber ring coated with an adhesive. In the present invention, the sodium naphthalene solution preferably comprises the following components in parts by weight: 30 parts of naphthalene, 7 parts of sodium and 63 parts of tetrahydrofuran. In the present invention, the treatment time of the sodium naphthalene solution is preferably 2 to 10 minutes, specifically preferably 2 minutes, 5 minutes, 8 minutes or 10 minutes; after the sodium naphthalene solution treatment, it is preferably further comprised of tetrahydrofuran washing, water washing and drying in sequence. In the present invention, the coated surface of the fluoroplastic film is treated with a sodium naphthalene solution, which improves the adhesion performance of the fluoroplastic film and the EPDM rubber ring.

[0065] In the present invention, the pre-forming is preferably carried out in a pre-forming mold, and the schematic diagram of the pre-forming mold is as shown in Figure 1As shown. In the present invention, the temperature of the pre-forming mold is preferably 150-200°C, specifically preferably 150°C, 160°C, 170°C, 180°C, 190°C or 200°C. In the present invention, the molding pressure of the pre-forming molding is preferably 1-5MPa, specifically preferably 1MPa, 2MPa, 3MPa, 4MPa or 5MPa. In the present invention, the time of the pre-forming molding is preferably 2-10min, specifically preferably 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min or 10min. In the present invention, after the pre-forming molding, a fluoroplastic film with a pre-formed structure is obtained, and the schematic diagram of the fluoroplastic film with a pre-formed structure is as shown Figure 2 shown.

[0066] In the present invention, the schematic diagram of the assembly is as follows Figure 3 shown.

[0067] In the present invention, the temperature of the hot pressing vulcanization molding is preferably 150-160°C, and is preferably 150°C, 155°C or 160°C; the pressure is preferably 5-10MPa, and is preferably 5MPa, 6MPa, 7MPa, 8MPa, 9MPa or 10MPa; the time is preferably 20-40min, and is preferably 20min, 30min or 40min. In the present invention, the hot pressing vulcanization molding is preferably carried out in a sheath-type sealing ring molding mold, and the schematic diagram of the sheath-type sealing ring molding mold is as shown in Figure 4 shown.

[0068] After the hot pressing and vulcanization molding, the present invention preferably includes: demoulding after cooling.

[0069] In the present invention, the fluoroplastic film is closed and combined with the EPDM rubber ring.

[0070] The present invention also provides the use of the EPDM rubber material described in the above technical solution, the EPDM rubber material obtained by the preparation method, the coated rubber sealing ring, or the coated rubber sealing ring obtained by the preparation method in fuel tank sealing.

[0071] In the present invention, the fuel tank seal preferably includes a static seal or a dynamic seal.

[0072] The EPDM rubber material and the coated rubber sealing ring of the invention have good corrosion resistance to HAP solution and are suitable for O-rings with static sealing and dynamic sealing requirements.

[0073] The preparation and application of the EPDM rubber material and the coated rubber sealing ring provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0074] The raw materials used in the following examples and comparative examples are from:

[0075] EPDM raw rubber (EPR) was purchased from Alantai Rubber (Nantong) Chemical Industry Co., Ltd., with a Mooney viscosity of 65, an ethylene content of 48%, and a third monomer content of 9%;

[0076] Alkylphenol-formaldehyde resin was purchased from Arakawa Chemical Co., Ltd., Japan, with a molecular weight of 550 and a softening point of 130°C;

[0077] Carbon black N774 was purchased from Jinan DeLan Chemical Co., Ltd., with an iodine absorption value of 29 g / kg and a DBP absorption value of 72 cm 3 / 100g;

[0078] Carbon black N990 was purchased from Jinan DeLan Chemical Co., Ltd., with an iodine absorption value of 10 g / kg and a DBP absorption value of 35 cm 3 / 100g;

[0079] Carbon black N330 was purchased from Jinneng Chemical (Qingdao) Co., Ltd., with an iodine absorption value of 82 g / kg and a DBP absorption value of 114 cm 3 / 100g;

[0080] Nano-magnesium oxide was purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd. with a particle size of 20-30 nm;

[0081] Stearic acid was purchased from Jingxian Longyuan Chemical Co., Ltd.;

[0082] The anti-aging agent dicumyl peroxide was purchased from Wanqian Chemicals Co., Ltd.;

[0083] The anti-aging agent triallyl isocyanurate was purchased from Hubei Xinjiecheng Chemical Technology Co., Ltd.;

[0084] The vulcanizing agent sulfur was purchased from Shandong Xinglilai New Material Technology Co., Ltd. with a particle size of 10 to 30 μm;

[0085] Vulcanization accelerator DM was purchased from Hebei Dongming Chemical Technology Co., Ltd.;

[0086] Vulcanization accelerator TMTD was purchased from Hebei Dongming Chemical Technology Co., Ltd.;

[0087] Epoxy resin adhesive was purchased from Henkel;

[0088] HAP solution was purchased from Liming Chemical Research and Design Institute Co., Ltd.

[0089] Example 1

[0090] The EPDM rubber ring comprises the following components in parts by weight, based on 100 parts by weight of the total raw materials for preparation: 32 parts by weight of EPDM raw rubber (EPR), 10 parts by weight of alkylphenol-formaldehyde resin, 40 parts by weight of carbon black (N774:N990:N330=2:2:1), 5 parts by weight of nano-magnesium oxide, 3 parts by weight of stearic acid, 4 parts by weight of an anti-aging agent (the mass ratio of diisopropyl peroxide to triallyl isocyanurate is 7:3), 3 parts by weight of a vulcanizing agent sulfur, and 3 parts by weight of a vulcanization accelerator (DM:TMTD=1:1).

[0091] The preparation method of the coated rubber sealing ring is as follows:

[0092] The EPDM raw rubber, alkyl phenolic resin, carbon black, nano magnesium oxide, stearic acid, anti-aging agent, vulcanizing agent and vulcanization accelerator were mixed by an open mill at 85°C and 50rpm for 45 minutes to obtain a mixed rubber. The mixed rubber was weighed in a mold, shaped at 2MPa and 100°C for 2 minutes, and then hot-pressed on a flat vulcanizer at a temperature of 140°C, a pressure of 8MPa, and a vulcanization time of 2 minutes to obtain an EPDM rubber ring.

[0093] The coated surface of a polytetrafluoroethylene film having a thickness of 0.02 mm was immersed in a naphthalene sodium solution (the naphthalene sodium solution comprises the following components in parts by weight: 30 parts of naphthalene, 7 parts of sodium and 63 parts of tetrahydrofuran) for 10 minutes, and then washed with tetrahydrofuran, washed with water and dried in sequence. Figure 1 Pre-forming is performed in the pre-forming mold shown to obtain a fluoroplastic film with a pre-formed structure; the temperature of the pre-forming mold is 200° C., the pre-forming pressure is 1 MPa, and the time is 5 minutes.

[0094] Coat the surface of the EPDM rubber ring with epoxy resin adhesive (coating amount is 0.15 mg / cm 2 ) After the surface is dry, the fluoroplastic film with a predetermined structure is contacted with the adhesive and coated with the EPDM rubber ring. The formed assembly is placed in a coated sealing ring molding mold and then hot-pressed and vulcanized at a temperature of 160°C and a pressure of 5MPa for 30 minutes. After cooling, the mold is demoulded to obtain a coated rubber sealing ring.

[0095] Example 2

[0096] The EPDM rubber ring comprises the following components in parts by weight, based on 100 parts by weight of the total raw materials for preparation: 57 parts by weight of EPDM raw rubber (EPR), 5 parts by weight of alkylphenol-formaldehyde resin, 30 parts by weight of carbon black (N774:N990:N330=2:2:1), 5 parts by weight of nano-magnesium oxide, 1 part by weight of stearic acid, 1 part by weight of an anti-aging agent (the mass ratio of diisopropyl peroxide to triallyl isocyanurate is 7:3), 0.5 parts by weight of a vulcanizing agent sulfur, and 0.5 parts by weight of a vulcanization accelerator (DM:TMTD=1:1).

[0097] The preparation method of the coated rubber sealing ring is as follows:

[0098] The EPDM raw rubber, alkylphenolic resin, carbon black, nano magnesium oxide, stearic acid, anti-aging agent, vulcanizing agent and vulcanization accelerator were mixed by an open mill at 65°C and 30rpm for 50 minutes to obtain a mixed rubber. The mixed rubber was weighed in a mold, shaped at 5MPa and 80°C for 10 minutes, and then hot-pressed on a flat vulcanizer at a temperature of 120°C, a pressure of 3MPa, and a vulcanization time of 2 minutes to obtain an EPDM rubber ring.

[0099] The coated surface of a polytetrafluoroethylene film having a thickness of 0.01 mm was immersed in a naphthalene sodium solution (the naphthalene sodium solution comprises the following components in parts by weight: 30 parts of naphthalene, 7 parts of sodium and 63 parts of tetrahydrofuran) for 10 minutes, and then washed with tetrahydrofuran, washed with water and dried in sequence. Figure 1 Pre-forming is carried out in the pre-forming mold shown to obtain a fluoroplastic film with a pre-formed structure; the temperature of the pre-forming mold is 180° C., the pre-forming pressure is 1 MPa, and the time is 8 minutes.

[0100] Coat the surface of the EPDM rubber ring with epoxy resin adhesive (coating amount is 0.15 mg / cm 2 ) After the surface is dry, the fluoroplastic film with a predetermined structure is contacted with the adhesive and coated with the EPDM rubber ring. The formed assembly is placed in a coated sealing ring molding mold and then hot-pressed and vulcanized at a temperature of 160°C and a pressure of 5MPa for 30 minutes. After cooling, the mold is demoulded to obtain a coated rubber sealing ring.

[0101] Example 3

[0102] The EPDM rubber ring comprises the following components in parts by weight, based on 100 parts by weight of the total raw materials for preparation: 47 parts of EPDM raw rubber (EPR), 10 parts of alkylphenol-formaldehyde resin, 30 parts of carbon black (N774:N990:N330=2:2:1), 5 parts of nano-magnesium oxide, 2 parts of stearic acid, 2 parts of anti-aging agent (the mass ratio of diisopropyl peroxide and triallyl isocyanurate is 7:3), 2 parts of vulcanizing agent sulfur, and 2 parts of vulcanization accelerator (DM:TMTD=1:1).

[0103] The preparation method of the coated rubber sealing ring is as follows:

[0104] The EPDM raw rubber, alkyl phenolic resin, carbon black, nano magnesium oxide, stearic acid, anti-aging agent, vulcanizing agent and vulcanization accelerator were mixed by an open mill at 75°C and 45rpm for 35 minutes to obtain a mixed rubber. The mixed rubber was weighed in a mold, shaped at 5MPa and 95°C for 10 minutes, and then hot-pressed on a flat vulcanizer at a temperature of 120°C, a pressure of 7MPa, and a vulcanization time of 2 minutes to obtain an EPDM rubber ring.

[0105] The coated surface of a polytetrafluoroethylene film having a thickness of 0.01 mm was immersed in a naphthalene sodium solution (the naphthalene sodium solution comprises the following components in parts by weight: 30 parts of naphthalene, 7 parts of sodium and 63 parts of tetrahydrofuran) for 5 minutes, and then washed with tetrahydrofuran, washed with water and dried in sequence. Figure 1 Pre-forming is carried out in the pre-forming mold shown to obtain a fluoroplastic film with a pre-formed structure; the temperature of the pre-forming mold is 180° C., the pre-forming pressure is 1 MPa, and the time is 5 minutes.

[0106] Coat the surface of the EPDM rubber ring with epoxy resin adhesive (coating amount is 0.15 mg / cm 2 ) After the surface is dry, the fluoroplastic film with a predetermined structure is contacted with the adhesive and coated with the EPDM rubber ring. The formed assembly is placed in a coated sealing ring molding mold and then hot-pressed and vulcanized at a temperature of 160°C and a pressure of 5MPa for 30 minutes. After cooling, the mold is demoulded to obtain a coated rubber sealing ring.

[0107] Comparative Example 1

[0108] The difference from Example 1 is that the carbon black used is only carbon black N774.

[0109] Comparative Example 2

[0110] The difference from Example 1 is that the carbon black used is only carbon black N990.

[0111] Comparative Example 3

[0112] The difference from Example 1 is that the alkylphenol-formaldehyde resin is omitted.

[0113] Comparative Example 4

[0114] The difference from Example 1 is that nano magnesium oxide is omitted.

[0115] Comparative Example 5

[0116] The difference from Example 1 is that the polytetrafluoroethylene film is not treated with the sodium naphthalene solution.

[0117] The physical and mechanical properties of the EPDM rubber rings in the embodiments and comparative examples, as well as the interface shear strength between the EPDM rubber ring and the surface fluoroplastic film in the coated rubber sealing ring were tested. The results are shown in Table 1.

[0118] Table 1 Physical and mechanical properties and bonding strength properties of materials before and after corrosion

[0119]

[0120] It can be seen from Table 1 that the EPDM rubber ring of the present invention has higher tensile strength and elongation at break after being soaked in the HAP solution, and the interface shear strength between the EPDM rubber ring and the fluoroplastic film is significantly improved.

[0121] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An EPDM rubber material, characterized in that: Taking the total weight of the raw materials as 100 parts, the EPDM rubber material includes the following raw materials in parts by weight: 20-70 parts of EPDM raw rubber, 5-10 parts of tackifying resin, 30-45 parts of wear-resistant filler, 1-7 parts of plasticizer, 0.1-5 parts of anti-aging agent, 0.5-3 parts of vulcanizing agent, and 0.1-3 parts of vulcanization accelerator; The wear-resistant filler comprises carbon black and nano magnesium oxide, and the mass ratio of the carbon black to the nano magnesium oxide is 5:1 to 20:

1.

2. The EPDM rubber material according to claim 1, characterized in that: The carbon black includes carbon black N774, carbon black N990 and carbon black N330, and the mass ratio of the carbon black N774, carbon black N990 and carbon black N330 is 2:2:

1.

3. The EPDM rubber material according to claim 1, characterized in that: The tackifying resin is an alkylphenol-formaldehyde resin, the molecular weight of the alkylphenol-formaldehyde resin is 500-700, and the softening point is 120-140°C.

4. The EPDM rubber material according to claim 1, characterized in that: The Mooney viscosity of the EPDM raw rubber is 50-80, the ethylene content is 30-60%, and the third monomer content is 4-10%; The plasticizer is stearic acid; The anti-aging agent comprises dicumyl peroxide and triallyl isocyanurate, and the mass of the dicumyl peroxide is not less than 70% of the total mass of the dicumyl peroxide and triallyl isocyanurate; The vulcanizing agent is sulfur; The vulcanization accelerator includes dibenzothiazole disulfide and dimethyl bisthiocarbonyl disulfide, wherein the mass ratio of dibenzothiazole disulfide to dimethyl bisthiocarbonyl disulfide is 1:

1.

5. The method for preparing the EPDM rubber material according to any one of claims 1 to 4, characterized in that: The following steps are involved: The prepared raw materials are sequentially mixed, shaped and hot-pressed to obtain the EPDM rubber material.

6. A coated rubber sealing ring, characterized in that: It comprises an EPDM rubber ring and a fluoroplastic film covering the EPDM rubber ring; the EPDM rubber ring and the fluoroplastic film are bonded by an adhesive; the EPDM rubber ring is made of the EPDM rubber material according to any one of claims 1 to 4 or the EPDM rubber material prepared by the preparation method according to claim 5.

7. The coated rubber sealing ring according to claim 6, characterized in that: The material of the fluoroplastic film includes polytetrafluoroethylene, fusible polytetrafluoroethylene or ethylene-tetrafluoroethylene copolymer, and the thickness of the fluoroplastic film is 0.005-0.05 mm; The adhesive is an epoxy resin adhesive.

8. The method for preparing the coated rubber sealing ring according to any one of claims 6 to 7, characterized in that: The following steps are involved: Provide EPDM rubber ring; After the adhesive is coated on the surface of the EPDM rubber ring and dried, a fluoroplastic film is brought into contact with the adhesive and covers the EPDM rubber ring. The formed assembly is subjected to hot pressing and vulcanization molding to obtain the coated rubber sealing ring.

9. The preparation method according to claim 8, characterized in that: Before the fluoroplastic film is coated, the method further comprises: treating the coated surface of the fluoroplastic film with a sodium naphthalene solution, and then performing pre-forming; The temperature of the hot pressing vulcanization molding is 150-60° C., the pressure is 5-10 MPa, and the time is 20-40 minutes.

10. Use of the EPDM rubber material according to any one of claims 1 to 4, the EPDM rubber material obtained by the preparation method according to claim 5, the coated rubber sealing ring according to any one of claims 6 to 7, or the coated rubber sealing ring obtained by the preparation method according to any one of claims 8 to 9 in fuel tank sealing.

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