An aging-resistant rubber sealing ring and its preparation method

Abstract

This invention relates to the field of sealing ring technology, and proposes an aging-resistant rubber sealing ring and its preparation method. An aging-resistant rubber sealing ring comprises the following components in parts by weight: 70-80 parts of nitrile rubber, 20-25 parts of chloroprene rubber, 20-30 parts of filler, 3-4 parts of activator, 1-2 parts of co-activator, 2-3 parts of antioxidant, 4-8 parts of plasticizer, 2-3 parts of crosslinking agent, and 1-2 parts of accelerator; the filler includes modified carbon nanotubes and nylon 66 fiber; the preparation method of modified carbon nanotubes includes the following steps: A1, adding carbon nanotubes to mixed acid, soaking, filtering, and drying to obtain pretreated carbon nanotubes; A2, adding the pretreated carbon nanotubes and methyl cyanobenzoate to ethyl acetate, stirring, concentrating, and drying to obtain modified carbon nanotubes. Through the above technical solution, the problem of poor aging resistance of rubber sealing rings in related technologies is solved.

Description

Technical Field

[0001] This invention relates to the field of sealing ring technology, specifically to an aging-resistant rubber sealing ring and its preparation method. Background Technology

[0002] In industrial production and equipment operation, rubber seals are core components for achieving sealing functions, and their performance stability directly affects the safety and efficiency of the entire system. Traditional rubber seals generally use nitrile rubber and neoprene rubber as the main materials, and during long-term use, they often face multiple challenges from complex environmental factors. In particular, the problem of thermal oxidation and corrosion under high-temperature conditions often leads to seal failure.

[0003] To address these challenges, the industry has attempted to add carbon nanotubes, finding that they have a certain effect in delaying aging. However, carbon nanotubes are prone to aggregation, resulting in limited improvement in the aging resistance of rubber seals. Therefore, as the demand for the aging resistance of rubber seals continues to increase, the existing method of adding carbon nanotubes is no longer sufficient to meet the requirements.

[0004] Therefore, developing rubber seals with excellent aging resistance has become a key direction for solving industry pain points and meeting practical application needs. Summary of the Invention

[0005] This invention proposes an aging-resistant rubber sealing ring and its preparation method, which solves the problem of poor aging resistance of rubber sealing rings in related technologies.

[0006] The technical solution of the present invention is as follows:

[0007] This invention proposes an aging-resistant rubber sealing ring, the raw materials of which include the following components in parts by weight: 70-80 parts of nitrile rubber, 20-25 parts of chloroprene rubber, 20-30 parts of filler, 3-4 parts of activator, 1-2 parts of co-activator, 2-3 parts of antioxidant, 4-8 parts of plasticizer, 2-3 parts of crosslinking agent, and 1-2 parts of accelerator;

[0008] The fillers mentioned above include modified carbon nanotubes and nylon 66 fibers;

[0009] The preparation method of the above-mentioned modified carbon nanotubes includes the following steps:

[0010] A1. Add carbon nanotubes to mixed acid, soak, filter, and dry to obtain pretreated carbon nanotubes.

[0011] A2. The pretreated carbon nanotubes and methyl p-cyanobenzoate were added to ethyl acetate, stirred, concentrated, and dried to obtain the modified carbon nanotubes.

[0012] As a further technical solution, the mass ratio of the aforementioned carbon nanotubes to methyl p-cyanobenzoate is 40~50:1.

[0013] In the aging-resistant rubber sealing ring of the present invention, the mass ratio of carbon nanotubes to methyl cyanobenzoate can be 40:1, 41:1, 42:1, 43:1, 44:1, 45:1, 46:1, 47:1, 48:1, 49:1, or 50:1, preferably 50:1.

[0014] As a further technical solution, the mass ratio of the modified carbon nanotubes to nylon 66 fibers is 1:1.5~2.

[0015] As a further technical solution, the preparation method of the above-mentioned mixed acid includes the following steps:

[0016] Sulfuric acid and nitric acid are mixed at a volume ratio of 1:3~4 to obtain the above mixed acid.

[0017] As a further technical solution, the mass fraction of the sulfuric acid and nitric acid mentioned above is 80% each independently.

[0018] As a further technical solution, the mass-to-volume ratio of the aforementioned carbon nanotubes and mixed acid is 1g:10~12mL.

[0019] As a further technical solution, the soaking temperature is 80~90℃ and the soaking time is 3~4h.

[0020] As a further technical solution, the mass-to-volume ratio of the aforementioned carbon nanotubes and ethyl acetate is 1g:15~18mL.

[0021] As a further technical solution, in step A2, the stirring temperature is 50~60℃, the stirring speed is 200~300rpm, and the stirring time is 3~4h.

[0022] As a further technical solution, the aforementioned nylon 66 fiber is an impregnated nylon 66 fiber;

[0023] The above impregnation treatment includes the following steps:

[0024] After cleaning and drying, nylon 66 fibers are immersed in an impregnation solution for 30-35 seconds, then removed and dried to obtain the above-mentioned impregnated nylon 66 fibers.

[0025] As a further technical solution, the raw materials of the above-mentioned impregnation solution include the following components in parts by weight:

[0026] 5-8 parts glycidyl ether, 1-2 parts dopamine, 2-3 parts m-phenylenediamine, 3-4 parts 2-amino-3-hydroxybenzoic acid, 40-50 parts chloroprene latex, and 80-90 parts water.

[0027] In this invention, the aging-resistant rubber sealing ring addresses the issue that existing impregnation techniques result in weak adhesion between nylon 66 fibers and other materials in the system after impregnation, preventing nylon 66 fibers from fully utilizing their mechanical properties as a skeleton material. Therefore, 2-amino-3-hydroxybenzoic acid is added to the impregnation solution. The 2-amino-3-hydroxybenzoic acid molecule contains multiple groups capable of forming hydrogen bonds, giving the impregnated nylon 66 fibers a stronger ability to form hydrogen bonds in the system and resulting in stronger adhesion to other materials, thus improving the tensile strength of the aging-resistant rubber sealing ring.

[0028] As a further technical solution, the aforementioned glycidyl ether includes one or both of ethylene glycol diglycidyl ether and diethylene glycol diglycidyl ether.

[0029] As a further technical solution, the preparation method of the above-mentioned impregnation solution includes the following steps:

[0030] B1. Add dopamine to a portion of water to obtain a dopamine aqueous solution with a mass concentration of 10%~15%;

[0031] B2. Add glycidyl ether to the above-mentioned dopamine aqueous solution and react to obtain the reaction solution;

[0032] B3. Add m-phenylenediamine to the above reaction solution, stir for the first time, add the remaining water, add 2-amino-3-hydroxybenzoic acid, add chloroprene latex, stir for the second time, and obtain the above impregnation solution.

[0033] As a further technical solution, the temperature of the above reaction is 80~90℃ and the time is 0.5~1h.

[0034] As a further technical solution, the temperature of the first stirring is 30~40℃, the speed is 200~300rpm, and the time is 0.5~1h.

[0035] As a further technical solution, the temperature of the second stirring is 30~40℃, the speed is 200~300rpm, and the time is 2~2.5h.

[0036] As a further technical solution, the aforementioned activator includes one or both of zinc oxide and magnesium oxide.

[0037] In the aging-resistant rubber sealing ring of the present invention, the activator can be any one or more of conventional activators, such as any one or more of calcium oxide, lead oxide, zinc oxide, and magnesium oxide, preferably one or two of zinc oxide and magnesium oxide.

[0038] As a further technical solution, the aforementioned activator is stearic acid.

[0039] As a further technical solution, the antioxidant mentioned above includes one or two of antioxidant 4010NA and antioxidant MB.

[0040] In the aging-resistant rubber sealing ring of the present invention, the antioxidant can be any one or more of conventional antioxidants, such as antioxidant RD, antioxidant 6PPD, antioxidant AW, antioxidant DFC-34, antioxidant 4010NA, and antioxidant MB, preferably one or two of antioxidant 4010NA and antioxidant MB.

[0041] As a further technical solution, the plasticizer mentioned above includes one or both of dioctyl sebacate and dioctyl adipate.

[0042] In the aging-resistant rubber sealing ring of the present invention, the plasticizer can be any one or more of conventional plasticizers, such as dibutyl phthalate, dioctyl terephthalate, epoxidized soybean oil, chlorinated paraffin, dioctyl sebacate, and dioctyl adipate, preferably one or two of dioctyl sebacate and dioctyl adipate.

[0043] As a further technical solution, the crosslinking agent mentioned above is dicumyl peroxide.

[0044] As a further technical solution, the aforementioned accelerator includes one or both of accelerator M and accelerator DM.

[0045] In the aging-resistant rubber sealing ring of the present invention, the accelerator can be any one or more of conventional accelerators, such as any one or more of accelerator CZ, accelerator TMTD, accelerator D, accelerator M, and accelerator DM, preferably one or two of accelerator M and accelerator DM.

[0046] This invention also proposes a method for preparing an aging-resistant rubber sealing ring, which includes the following steps:

[0047] S1. Nitrile rubber and chloroprene rubber are mixed and then plasticized to obtain plasticized rubber;

[0048] S2. Mix the plasticized rubber with the remaining raw material components of the aging-resistant rubber sealing ring, and vulcanize to obtain the above-mentioned aging-resistant rubber sealing ring.

[0049] The working principle and beneficial effects of this invention are as follows:

[0050] In this invention, modified carbon nanotubes are prepared to improve the aging resistance of rubber sealing rings. Unlike existing technologies that directly add carbon nanotubes, this invention addresses the tendency of carbon nanotubes to aggregate in rubber systems. Therefore, this invention first treats the carbon nanotubes with acid to introduce polar groups onto their surface, initially altering their surface chemical properties to facilitate further modification. In step A2, the pretreated carbon nanotubes are composited with methyl cyanobenzoate. The resulting composite carbon nanotubes exhibit altered surface structures, and the introduced functional groups improve their compatibility with the rubber matrix surface properties, resulting in more uniform dispersion in the rubber raw material. This prevents agglomeration of the carbon nanotubes and fully utilizes their aging resistance, thus improving the aging resistance of the rubber sealing rings. Detailed Implementation

[0051] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0052] In the following examples and comparative examples, the nitrile rubber was Nipol 1043, the chloroprene rubber was CR232, purchased from Chongqing Changshou Chemical Co., Ltd., the magnesium oxide had a particle size of 1 μm, the zinc oxide had a particle size of 1 μm, the carbon nanotubes were TF-300, purchased from Shandong Carbon Peak New Material Technology Co., Ltd., the nylon 66 fiber had a length of 3 mm and a diameter of 20 μm, the sulfuric acid had a mass fraction of 80%, the nitric acid had a mass fraction of 80%, the ethylene glycol diglycidyl ether was Darl-1, purchased from Hubei Darli Chemical Co., Ltd., the chloroprene latex was CL-1045, purchased from Kaiming Plastics (Dongguan) Co., Ltd., and the diethylene glycol diglycidyl ether was 950021, purchased from Zhongshan Dixing Chemical Co., Ltd.

[0053] Example 1

[0054] An aging-resistant rubber sealing ring, the raw materials of which include the following components in parts by weight: 80 parts of nitrile rubber, 25 parts of chloroprene rubber, 30 parts of filler, 4 parts of zinc oxide, 2 parts of stearic acid, 3 parts of antioxidant 4010NA, 8 parts of dioctyl sebacate, 3 parts of dicumyl peroxide, and 2 parts of accelerator M.

[0055] The filler consists of modified carbon nanotubes and nylon 66 fibers in a mass ratio of 1:2;

[0056] The preparation method of modified carbon nanotubes includes the following steps:

[0057] A1. Add carbon nanotubes to a mixed acid (the mixed acid is obtained by mixing sulfuric acid and nitric acid in a volume ratio of 1:4, and the mass-volume ratio of carbon nanotubes to mixed acid is 1g:12mL), soak at 90℃ for 3h, filter, and dry to obtain pretreated carbon nanotubes.

[0058] A2. Pretreated carbon nanotubes and methyl cyanobenzoate (mass ratio of carbon nanotubes to methyl cyanobenzoate is 30:1) were added to ethyl acetate (mass volume ratio of carbon nanotubes to ethyl acetate is 1g:18mL), stirred at 300rpm for 3h at 60℃, concentrated, and dried to obtain modified carbon nanotubes.

[0059] The preparation method of the aging-resistant rubber sealing ring includes the following steps:

[0060] S1. Mix nitrile rubber and chloroprene rubber and then plasticize for 15 minutes to obtain plasticized rubber.

[0061] S2. Mix the plasticized rubber with the remaining raw material components of the aging-resistant rubber sealing ring for 4 minutes, put it into the mold, and vulcanize to obtain the aging-resistant rubber sealing ring.

[0062] Example 2

[0063] An aging-resistant rubber sealing ring, the raw materials of which include the following components in parts by weight: 70 parts of nitrile rubber, 20 parts of chloroprene rubber, 20 parts of filler, 3 parts of magnesium oxide, 1 part of stearic acid, 2 parts of antioxidant MB, 4 parts of dioctyl adipate, 2 parts of dicumyl peroxide, and 1 part of accelerator DM.

[0064] The filler consists of modified carbon nanotubes and nylon 66 fibers in a mass ratio of 1:1.5;

[0065] The preparation method of modified carbon nanotubes includes the following steps:

[0066] A1. Add carbon nanotubes to a mixed acid (the mixed acid is obtained by mixing sulfuric acid and nitric acid in a volume ratio of 1:3, and the mass-volume ratio of carbon nanotubes to mixed acid is 1g:10mL), soak at 80℃ for 3h, filter, and dry to obtain pretreated carbon nanotubes.

[0067] A2. Pretreated carbon nanotubes and methyl cyanobenzoate (mass ratio of carbon nanotubes to methyl cyanobenzoate is 30:1) were added to ethyl acetate (mass volume ratio of carbon nanotubes to ethyl acetate is 1g:15mL), stirred at 200rpm for 4h at 50℃, concentrated, and dried to obtain modified carbon nanotubes.

[0068] The preparation method of the aging-resistant rubber sealing ring includes the following steps:

[0069] S1. Mix nitrile rubber and chloroprene rubber and then plasticize for 10 minutes to obtain plasticized rubber.

[0070] S2. Mix the plasticized rubber with the remaining raw material components of the aging-resistant rubber sealing ring for 2 minutes, put it into the mold, and vulcanize to obtain the aging-resistant rubber sealing ring.

[0071] Example 3

[0072] The only difference between this embodiment and Embodiment 2 is that the mass ratio of carbon nanotubes to methyl cyanobenzoate in this embodiment is 60:1.

[0073] Example 4

[0074] The only difference between this embodiment and Embodiment 2 is that the mass ratio of carbon nanotubes to methyl cyanobenzoate in this embodiment is 40:1.

[0075] Example 5

[0076] The only difference between this embodiment and Embodiment 2 is that the mass ratio of carbon nanotubes to methyl cyanobenzoate in this embodiment is 50:1.

[0077] Example 6

[0078] The only difference between this embodiment and embodiment 5 is that the nylon 66 fiber in this embodiment is an impregnated nylon 66 fiber;

[0079] The impregnation process includes the following steps:

[0080] After washing and drying, nylon 66 fibers are immersed in an impregnation solution for 35 seconds, then removed and dried to obtain impregnated nylon 66 fibers.

[0081] The impregnation solution comprises the following components by weight:

[0082] 8 parts ethylene glycol diglycidyl ether, 2 parts dopamine, 3 parts m-phenylenediamine, 4 parts 2-amino-3-hydroxybenzoic acid, 50 parts chloroprene latex, and 90 parts water;

[0083] The method for preparing the impregnation solution includes the following steps:

[0084] B1. Add dopamine to a portion of water to obtain a 15% dopamine aqueous solution by mass.

[0085] B2. Add ethylene glycol diglycidyl ether to an aqueous solution of dopamine and react at 90°C for 1 hour to obtain a reaction solution;

[0086] B3. Add m-phenylenediamine to the reaction solution and stir at 300 rpm for 0.5 h at 40 °C. Add the remaining water, 2-amino-3-hydroxybenzoic acid, and chloroprene latex. Stir at 300 rpm for 2 h at 40 °C to obtain the impregnation solution.

[0087] Example 7

[0088] The only difference between this embodiment and embodiment 5 is that the nylon 66 fiber in this embodiment is an impregnated nylon 66 fiber;

[0089] The impregnation process includes the following steps:

[0090] After washing and drying, nylon 66 fibers are immersed in an impregnation solution for 30 seconds, then removed and dried to obtain impregnated nylon 66 fibers.

[0091] The impregnation solution comprises the following components by weight:

[0092] 5 parts diethylene glycol diglycidyl ether, 1 part dopamine, 2 parts m-phenylenediamine, 3 parts 2-amino-3-hydroxybenzoic acid, 40 parts chloroprene latex, and 80 parts water;

[0093] The method for preparing the impregnation solution includes the following steps:

[0094] B1. Add dopamine to a portion of water to obtain a 10% dopamine aqueous solution;

[0095] B2. Diethylene glycol diglycidyl ether was added to an aqueous solution of dopamine and reacted at 80°C for 0.5 h to obtain a reaction solution.

[0096] B3. Add m-phenylenediamine to the reaction solution and stir at 200 rpm for 1 hour at 30°C. Add the remaining water, 2-amino-3-hydroxybenzoic acid, and chloroprene latex. Stir at 200 rpm for 2.5 hours at 30°C to obtain the impregnation solution.

[0097] Comparative Example 1

[0098] The only difference between this comparative example and Example 2 is that the modified carbon nanotubes in this comparative example are replaced with carbon nanotubes of equal mass.

[0099] Experimental Example 1

[0100] The aging-resistant rubber sealing rings prepared in Examples 1-5 and Comparative Example 1 were tested for tensile strength according to the method specified in GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The samples were then heat-treated at 120℃ for 80 hours, and their tensile strength was tested again according to the method specified in GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The test samples were type 1A dumbbell-shaped samples, and the tensile rate was 500 mm / min. The tensile strength test results are shown in Table 1.

[0101] Table 1 Tensile strength test results

[0102]

[0103] As shown in Table 1, the tensile strength of the aging-resistant rubber sealing rings prepared in Examples 1-5 of the present invention decreased after aging treatment. Therefore, the present invention improves the aging resistance of the rubber sealing rings by using methyl cyanobenzoate composite after acid treatment of carbon nanotubes.

[0104] Experimental Example 2

[0105] The aging-resistant rubber sealing rings prepared in Examples 5-7 were tested for tensile strength according to the method specified in GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The test specimens were type 1A dumbbell-shaped specimens, and the tensile rate was 500 mm / min. The test results are shown in Table 2.

[0106] Table 2 Tensile strength test results

[0107]

[0108] As shown in Table 2, the tensile strength of the aging-resistant rubber sealing rings prepared in Examples 6-7 of the present invention reached more than 24.5 MPa. Therefore, the present invention improves the tensile strength of the aging-resistant rubber sealing ring by impregnating nylon 66 fibers and adding 2-amino-3-hydroxybenzoic acid to the impregnation solution.

[0109] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aging-resistant rubber sealing ring, characterized in that, The raw materials include the following components in parts by weight: 70-80 parts of nitrile rubber, 20-25 parts of chloroprene rubber, 20-30 parts of filler, 3-4 parts of activator, 1-2 parts of co-activator, 2-3 parts of antioxidant, 4-8 parts of plasticizer, 2-3 parts of crosslinking agent, and 1-2 parts of accelerator; The filler comprises modified carbon nanotubes and nylon 66 fibers; The method for preparing the modified carbon nanotubes includes the following steps: A1. Add carbon nanotubes to mixed acid, soak, filter, and dry to obtain pretreated carbon nanotubes. A2. The pretreated carbon nanotubes and methyl p-cyanobenzoate were added to ethyl acetate, stirred, concentrated, and dried to obtain the modified carbon nanotubes. The mass ratio of the carbon nanotubes to methyl p-cyanobenzoate is 40-50:1; The nylon 66 fiber is an impregnated nylon 66 fiber; the impregnation process includes the following steps: washing and drying the nylon 66 fiber, immersing it in an impregnation solution for 30-35 seconds, removing it, and drying it to obtain the impregnated nylon 66 fiber. The impregnation solution comprises the following components by weight: 5-8 parts glycidyl ether, 1-2 parts dopamine, 2-3 parts m-phenylenediamine, 3-4 parts 2-amino-3-hydroxybenzoic acid, 40-50 parts chloroprene latex, and 80-90 parts water.

2. The aging-resistant rubber sealing ring according to claim 1, characterized in that, The mass ratio of the modified carbon nanotubes to nylon 66 fibers is 1:1.5~2.

3. The aging-resistant rubber sealing ring according to claim 1, characterized in that, The preparation method of the mixed acid includes the following steps: Sulfuric acid and nitric acid are mixed at a volume ratio of 1:3~4 to obtain the mixed acid.

4. The aging-resistant rubber sealing ring according to claim 1, characterized in that, The glycidyl ether includes one or both of ethylene glycol diglycidyl ether and diethylene glycol diglycidyl ether.

5. The aging-resistant rubber sealing ring according to claim 1, characterized in that, The method for preparing the impregnation solution includes the following steps: B1. Add dopamine to a portion of water to obtain a dopamine aqueous solution with a mass concentration of 10%~15%; B2. Add glycidyl ether to the dopamine aqueous solution and react to obtain a reaction solution; B3. Add m-phenylenediamine to the reaction solution, stir for the first time, add the remaining water, add 2-amino-3-hydroxybenzoic acid, add chloroprene latex, stir for the second time, and obtain the impregnation solution.

6. The aging-resistant rubber sealing ring according to claim 1, characterized in that, The activator includes one or two of zinc oxide and magnesium oxide; The activator is stearic acid; The antioxidant includes one or two of antioxidant 4010NA and antioxidant MB; The plasticizer includes one or both of dioctyl sebacate and dioctyl adipate; The crosslinking agent is dicumyl peroxide; The accelerator includes one or both of accelerator M and accelerator DM.

7. A method for preparing an aging-resistant rubber sealing ring, used to prepare an aging-resistant rubber sealing ring as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Nitrile rubber and chloroprene rubber are mixed and then plasticized to obtain plasticized rubber; S2. Mix the plasticized rubber with the remaining raw material components of the aging-resistant rubber sealing ring, and vulcanize to obtain the aging-resistant rubber sealing ring.

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