High sealing property anti-aging rubber shock absorbing washer and preparation method thereof

Abstract

The application discloses a high-sealing anti-aging rubber shock-absorbing gasket and a preparation method thereof, and relates to the technical field of rubber gaskets. The high-sealing anti-aging rubber shock-absorbing gasket is prepared from the following raw materials in parts by mass: a rubber matrix 100 parts, a reinforcing agent 30-60 parts, a plasticizer 5-20 parts, zinc oxide 3-8 parts, stearic acid 1-3 parts, an anti-aging agent 1-3 parts, a vulcanizing agent 1.5-3.5 parts, and a promoter 1.0-2.5 parts. Compared with the prior art, the application can adapt to the harsh use requirements of mechanical equipment, pipelines, automobiles and other fields, and can reduce the frequency of operation and maintenance replacement caused by performance defects, by matching the raw material components with the preparation process.

Description

Technical Field

[0001] This invention relates to the field of rubber gasket technology, specifically to a high-sealing, anti-aging rubber shock-absorbing gasket and its preparation method. Background Technology

[0002] Rubber vibration damping washers are key basic components in mechanical equipment, pipeline systems, and the automotive industry, serving the dual functions of vibration damping and sealing protection. Their performance stability directly affects the overall operational safety and service life of the machine. In practical applications, these washers often face complex and harsh operating environments, such as alternating high and low temperatures, oxygen, ozone, ultraviolet radiation, and acid and alkaline media corrosion. These factors can accelerate the degradation, cross-linking, or breakage of rubber molecular chains, leading to aging.

[0003] Existing rubber vibration damping washers generally suffer from insufficient aging resistance, mainly manifested in increased hardness, decreased elasticity, and reduced tensile strength after long-term use, and even defects such as cracking, embrittlement, and deformation. This not only significantly weakens the shock absorption effect of the washers, making them unable to effectively absorb vibration energy and reduce noise, but also causes sealing performance failure, leading to safety hazards such as media leakage and component corrosion. In severe cases, frequent downtime for replacement is required, increasing operation and maintenance costs.

[0004] Currently, most rubber gaskets on the market use traditional antioxidants such as amines and phenolic compounds. These antioxidants have drawbacks such as a narrow anti-aging spectrum and easy migration and volatilization, making it difficult to resist the synergistic effects of multiple aging factors in the long term. At the same time, some formulations, in pursuit of single performance characteristics such as vibration damping or sealing, neglect the synergistic effects between components, resulting in a difficulty in achieving a balance between aging resistance, mechanical properties, and processing performance. Therefore, developing a rubber vibration damping gasket with a reasonable formulation, excellent aging resistance, and the ability to balance high sealing performance and stable vibration damping has become a pressing technical challenge in the industry, and is of great significance for improving the reliability and service life of related equipment. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a high-sealing anti-aging rubber damping washer and its preparation method. By optimizing the raw material formula, using an anti-aging agent with a specific structure, and combining it with a suitable rubber matrix and additives, it significantly improves the aging resistance and extends the service life while ensuring excellent damping performance and high sealing performance, thus meeting the needs of use under complex working conditions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a high-sealing, anti-aging rubber shock-absorbing washer, made from raw materials comprising the following parts by weight: 100 parts rubber matrix, 30-60 parts reinforcing agent, 5-20 parts plasticizer, 3-8 parts zinc oxide, 1-3 parts stearic acid, 1-3 parts anti-aging agent, 1.5-3.5 parts vulcanizing agent, and 1.0-2.5 parts accelerator;

[0007] The antioxidant is a compound represented by chemical formula 1;

[0008] The structure of chemical formula 1 is as follows: ;

[0009] R1 in the chemical formula 1 is a substituent, and R1 is any one of hydrogen, cyano, hydroxyl and methyl.

[0010] Furthermore, the rubber matrix is ​​at least one of nitrile rubber, chloroprene rubber, or ethylene propylene diene monomer (EPDM) rubber.

[0011] Furthermore, the reinforcing agent is at least one of carbon black, silica, and diatomaceous earth;

[0012] The carbon black is one of N330, N550 or N770.

[0013] Furthermore, the plasticizer is at least one of dioctyl phthalate, dioctyl adipate, and dioctyl sebacate.

[0014] Furthermore, the vulcanizing agent is one of sulfur, dicumyl peroxide, or bis-tert-butylperoxide.

[0015] Furthermore, the accelerator is at least one of accelerator CZ, accelerator DM, accelerator TMTD, or accelerator BZ.

[0016] Furthermore, the antioxidant is any one of the compounds shown in the following structures:

[0017] ;

[0018] .

[0019] A method for preparing a high-sealing, anti-aging rubber damping washer comprises the following steps:

[0020] (1) First stage of mixing: The rubber matrix is ​​put into an internal mixer and plasticized for 5-15 minutes. Then, the zinc oxide, stearic acid, antioxidant, plasticizer and 1 / 2 part by weight of reinforcing agent are added in sequence. The mixture is mixed at 70-100℃ for 15-45 minutes and the rubber is discharged to obtain the first stage of compound.

[0021] (2) Two-stage mixing: After cooling the first-stage compound to room temperature, put it back into the internal mixer, add 1 / 2 part by weight of reinforcing agent, mix at 60-90℃ for 15-45 minutes, and discharge the compound again to obtain the second-stage compound.

[0022] (3) Final mixing: After cooling the two-stage compound to room temperature, add the vulcanizing agent and accelerator to the open mill, and make a thin triangular package 5-8 times. Control the roller temperature to below 50°C. After mixing evenly, sheet out to obtain the final compound.

[0023] (4) Molding and vulcanization: After the final rubber compound is placed in a preheated mold, it is molded and vulcanized at 150-180℃ and 10-20MPa. After demolding, the high-sealing anti-aging rubber shock-absorbing gasket is obtained.

[0024] Furthermore, the number of times the thin-walled triangular package is punched is 6, and the roller gap is 0.5-1.0mm.

[0025] Furthermore, steps (1) and (2) are performed under a nitrogen atmosphere.

[0026] The antioxidant described in this invention inhibits the aging process of rubber through the synergistic effect of phenolic hydroxyl groups, amino groups, and conjugated structures at multiple stages: the active hydrogen in the phenolic hydroxyl group can quickly capture active free radicals such as hydroxyl radicals and alkoxy radicals generated during rubber aging, generating stable phenolic oxygen radicals, directly terminating the free radical chain reaction, and preventing the rubber molecular chain from breaking or excessively cross-linking due to free radical attack; the amino group, as a strong electron-donating group, can react with peroxides such as hydrogen peroxide generated by rubber oxidation, decomposing them into substances and blocking secondary oxidation caused by peroxides; on the other hand, it can regenerate phenolic oxygen radicals into phenolic hydroxyl groups through electron transfer, forming a cycle of "free radical capture - phenolic hydroxyl group regeneration", enhancing the free radical scavenging efficiency; and the conjugated structure, through the electron delocalization effect, can stabilize reaction intermediates such as phenolic oxygen radicals, reducing the risk of them triggering aging reactions again, and can also improve the structural stability of the antioxidant molecule and its compatibility in the rubber matrix, reducing the loss of the antioxidant due to volatilization and migration, ensuring its long-term continuous anti-aging effect, and ultimately ensuring that the elasticity, sealing performance, and mechanical properties of the rubber shock-absorbing gasket do not significantly decrease with the use time.

[0027] This invention addresses the technical problems of existing rubber damping gaskets—insufficient aging resistance, easy imbalance between damping and sealing performance, and narrow and easily migrating anti-aging spectrum of traditional antioxidants—by synergistically formulating the various raw material components and balancing anti-aging enhancement, mechanical properties, and functional stability. The core antioxidant with a specific structure achieves broad-spectrum, long-lasting anti-aging through free radical capture, peroxide decomposition, and its own low migration. It also synergizes with the nitrile rubber, neoprene rubber, or EPDM rubber matrix—the matrix's inherent oil and weather resistance, combined with the antioxidant's antioxidant's anti-oxidation and anti-ozone capabilities, significantly resists corrosion under complex working conditions such as high and low temperatures, acids, and alkalis. The reinforcing agent, on the one hand, enhances the gasket's mechanical strength and elastic recovery through strong interfacial bonding with the rubber matrix. On the one hand, it provides the structural support required for shock absorption and cushioning. On the other hand, it can adsorb antioxidant molecules to reduce their migration and loss, and extend the action period of antioxidants. Plasticizers maintain the elasticity of gaskets during long-term use by adjusting the cross-linking density and hardness of the matrix, avoiding hardening and embrittlement caused by aging. At the same time, it forms a vulcanization synergistic system with vulcanizing agents, accelerators and activators - zinc oxide and stearic acid activate the vulcanization reaction, promote the uniform construction of a stable cross-linking network by vulcanizing agents and accelerators, improve the structural density of gaskets to ensure high sealing performance, and avoid excessive breakage or cross-linking of molecular chains through appropriate cross-linking. It works synergistically with antioxidants to maintain stable mechanical properties, and finally achieves synergistic optimization of the three core properties of aging resistance, shock absorption and sealing, and solves the defects of existing technologies.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. Superior aging resistance: Compared with the problems of narrow anti-aging spectrum and easy migration of traditional antioxidants in the prior art, the present invention can resist the influence of complex working conditions such as high and low temperature, ultraviolet rays and media corrosion for a longer period of time through the synergistic effect of antioxidants with specific structures and rubber matrix, significantly delaying the aging process of rubber and extending the overall service life of gaskets.

[0030] 2. More stable performance balance: Existing technologies often pursue a single performance (such as shock absorption or sealing) while neglecting the synergy of multiple performances. This invention, through formula optimization, can better maintain mechanical properties (such as elasticity and strength) while ensuring high sealing performance and stable shock absorption effect, and avoid significant performance degradation after long-term use.

[0031] 3. Enhanced application adaptability: Compared to existing technologies that are prone to functional failure under complex working conditions, this invention, through the adaptation of raw material components and preparation processes, can meet the stringent usage requirements of various fields such as mechanical equipment, pipelines, and automobiles, reducing the frequency of maintenance and replacement due to performance defects. Attached Figure Description

[0032] Figure 1 This is the NMR spectrum of compound 3 in Preparation Example 1 of the present invention.

[0033] Figure 2This is the NMR spectrum of the antioxidant 1 of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Preparation Example 1:

[0036] Preparation of antioxidant 1:

[0037] ;

[0038] ;

[0039] CAS number of compound 1: 91-53-2;

[0040] CAS number of compound 2: 100388-02-1;

[0041] The CAS number for compound 4 is 13047-04-6.

[0042] Under a nitrogen atmosphere, 10.00 g of compound 1, 12.48 g of compound 2, 8.84 g of sodium tert-butoxide, and 130 mL of toluene were added sequentially to the reaction system. The mixture was stirred until homogeneous, then 2.66 g of tetrakis(triphenylphosphine)palladium was added. The mixture was heated to 110 °C and refluxed for 10 h. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through silica gel. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with toluene. The combined organic phases were dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The solution was evaporated to dryness, and silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate as eluent. The solution was evaporated to dryness again to give 14.41 g of compound 3. Mass spectrometry (MS+H) was then performed. + :408, see MRI Figure 1 .

[0043] Under a nitrogen atmosphere, 14.41 g of compound 3, 4.42 g of compound 4, and 170 ml of DMF were added sequentially to the reaction system. After thorough stirring, 6.78 g of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride was added, and the mixture was stirred at 30 °C for 10 h. The mixture was filtered through silica gel, the solvent was evaporated, and silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate as eluent. The solution was evaporated to dryness to obtain 13.13 g of antioxidant 1. Mass spectrometry (MS+H) was then performed. + :515, see MRI Figure 2 .

[0044] Preparation Examples 2-4:

[0045] In Preparation Examples 2-4, antioxidants 2-4 were prepared sequentially, following the preparation method of Preparation Example 1, except that compound 4 was replaced. The rest remained the same as in Preparation Example 1. See Table 1 for details.

[0046] Table 1

[0047]

[0048] Example 1

[0049] Preparation of a high-sealing, anti-aging rubber damping washer:

[0050] 1. Raw material formula:

[0051] Rubber matrix: 100 parts of nitrile rubber;

[0052] Reinforcing agent: 45 parts of N330 carbon black;

[0053] Plasticizer: 12 parts dioctyl phthalate;

[0054] Zinc oxide: 5 parts;

[0055] Stearic acid: 2 parts;

[0056] Antioxidant: 1-2 parts of the antioxidant prepared in Example 1;

[0057] Vulcanizing agent: 2.0 parts sulfur;

[0058] Accelerator: 1.5 parts of accelerator CZ.

[0059] 2. Preparation method:

[0060] (1) First stage of mixing: Under nitrogen atmosphere, 100 parts of nitrile rubber were put into the internal mixer and plasticized for 10 minutes. Then, 5 parts of zinc oxide, 2 parts of stearic acid, 2 parts of antioxidant 1, 12 parts of dioctyl phthalate and 22.5 parts of N330 carbon black were added in sequence. The temperature of the internal mixer was controlled at 85°C. After mixing for 30 minutes, the rubber was discharged to obtain the first stage of mixed rubber.

[0061] (2) Two-stage mixing: Cool the first-stage compound to room temperature, put it back into the internal mixer under nitrogen atmosphere protection, add the remaining 22.5 parts of N330 carbon black, control the temperature at 75℃, mix for 25 minutes and then discharge the compound again to obtain the second-stage compound.

[0062] (3) Final mixing: Cool the two-stage compound to room temperature, transfer it to a two-roll mill, add 2.0 parts of sulfur and 1.5 parts of accelerator CZ, adjust the roller gap of the two-roll mill to 0.8 mm, make 6 thin triangular wraps, control the roller temperature not to exceed 45℃ throughout the process, and after uniform mixing, sheet it to obtain the final compound.

[0063] (4) Molding and vulcanization: After the final rubber compound is left to stand for 24 hours, it is placed in a mold preheated to 165°C and subjected to a pressure of 15MPa for molding vulcanization. The vulcanization time is 15 minutes. After the vulcanization is completed, the rubber is demolded to obtain a high-sealing anti-aging rubber shock-absorbing washer.

[0064] Examples 2-4

[0065] The preparation of a high-sealing anti-aging rubber shock-absorbing washer is carried out by referring to the preparation method of Example 1, except that the antioxidant 1 is replaced with antioxidant 2-antioxidant 4 in sequence, and the rest is the same as in Example 1.

[0066] Comparative Example 1

[0067] The preparation of a high-sealing anti-aging rubber shock-absorbing washer is carried out by referring to the preparation method of Example 1, except that the antioxidant 1 is replaced with antioxidant MB, and the rest is the same as in Example 1.

[0068] Comparative Example 2

[0069] The preparation of a high-sealing, anti-aging rubber damping washer, referring to the preparation method of Example 1, except that anti-aging agent 1 is replaced with anti-aging agent AW ( The rest remains the same as in Example 1.

[0070] Comparative Example 3

[0071] The preparation of a high-sealing anti-aging rubber shock-absorbing washer is carried out according to the preparation method of Example 1, except that the anti-aging agent 1 is not added, and the rest is the same as in Example 1.

[0072] Comparative Example 4

[0073] The preparation of a high-sealing anti-aging rubber shock-absorbing washer is carried out according to the preparation method of Example 1, without the addition of plasticizer, and otherwise remains the same as in Example 1.

[0074] Comparative Example 5

[0075] The preparation of a high-sealing anti-aging rubber shock-absorbing washer is carried out by referring to the preparation method of Example 1, except that the mass fraction of the reinforcing agent is replaced with 20 parts, and the rest is the same as in Example 1.

[0076] Performance testing:

[0077] Sample: A high-sealing, anti-aging rubber damping washer prepared in the examples and comparative examples.

[0078] 1. Mechanical property testing: The tensile strength of the specimen was tested in accordance with GB / T 528-2009, and the data are shown in Table 2.

[0079] 2. Aging resistance test:

[0080] 2.1 Place the sample in an aging chamber at 80℃ and maintain the temperature for 1200h. After removing it and cooling it to room temperature, test the tensile strength and calculate the tensile strength retention rate. The data are shown in Table 2.

[0081] 2.2 Place the sample in a UV aging test chamber with UV-340nm lamp source, temperature 60℃, and relative humidity 50% for 3000h. After cooling to room temperature, test the tensile strength and calculate the tensile strength retention rate. The data are shown in Table 2.

[0082] 3. Sealing performance test: Install the sample gasket at the standard flange interface to simulate the actual assembly state, introduce compressed air (test medium), raise the pressure to 15MPa, maintain it for 30min, and measure the leakage amount with a leak detector, in mL / min. The data are shown in Table 2.

[0083] Table 2

[0084]

[0085] Examples using antioxidants with specific structures maintained stable tensile strength, and their tensile strength retention rates after hot air aging and UV aging were superior to those of comparative examples using traditional antioxidants or without antioxidants, demonstrating better aging resistance. In terms of sealing performance, the examples and some comparative examples maintained low leakage levels, but the comparative examples without plasticizers or with reduced reinforcing agent dosage showed an increasing leakage trend, indicating that the compatibility of the raw material formulation has a significant impact on the sealing effect.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-sealing, anti-aging rubber shock-absorbing washer, characterized in that, It is made from raw materials containing the following parts by weight: 100 parts rubber matrix, 30-60 parts reinforcing agent, 5-20 parts plasticizer, 3-8 parts zinc oxide, 1-3 parts stearic acid, 1-3 parts antioxidant, 1.5-3.5 parts vulcanizing agent, and 1.0-2.5 parts accelerator; The antioxidant is a compound represented by chemical formula 1; The structure of chemical formula 1 is as follows: ; R1 in the chemical formula 1 is a substituent, and R1 is any one of hydrogen, cyano, hydroxyl and methyl.

2. The high-sealing, anti-aging rubber shock-absorbing washer according to claim 1, characterized in that, The rubber matrix is ​​at least one of nitrile rubber, chloroprene rubber, or ethylene propylene diene monomer (EPDM) rubber.

3. The high-sealing, anti-aging rubber shock-absorbing washer according to claim 1, characterized in that, The reinforcing agent is at least one of carbon black, silica, and diatomaceous earth. The carbon black is one of N330, N550 or N770.

4. The high-sealing, anti-aging rubber shock-absorbing washer according to claim 1, characterized in that, The plasticizer is at least one of dioctyl phthalate, dioctyl adipate, and dioctyl sebacate.

5. A high-sealing, anti-aging rubber shock-absorbing washer according to claim 1, characterized in that, The vulcanizing agent is one of sulfur, dicumyl peroxide, or bis-tert-butylperoxide.

6. The high-sealing, anti-aging rubber shock-absorbing washer according to claim 1, characterized in that, The accelerator is at least one of accelerator CZ, accelerator DM, accelerator TMTD, or accelerator BZ.

7. The high-sealing, anti-aging rubber shock-absorbing washer according to claim 1, characterized in that, The antioxidant is any one of the compounds shown in the following structures: ； 。 8. A method for preparing a high-sealing, anti-aging rubber damping washer as described in any one of claims 1-7, characterized in that, The following steps are required: (1) First stage of mixing: The rubber matrix is ​​put into an internal mixer and plasticized for 5-15 minutes. Then, the zinc oxide, stearic acid, antioxidant, plasticizer and 1 / 2 part by weight of reinforcing agent are added in sequence. The mixture is mixed at 70-100℃ for 15-45 minutes and the rubber is discharged to obtain the first stage of compound. (2) Two-stage mixing: After cooling the first-stage compound to room temperature, put it back into the internal mixer, add 1 / 2 part by weight of reinforcing agent, mix at 60-90℃ for 15-45 minutes, and discharge the compound again to obtain the second-stage compound. (3) Final mixing: After cooling the two-stage compound to room temperature, add the vulcanizing agent and accelerator to the open mill, and make a thin triangular package 5-8 times. Control the roller temperature to below 50°C. After mixing evenly, sheet out to obtain the final compound. (4) Molding and vulcanization: After the final rubber compound is placed in a preheated mold, it is molded and vulcanized at 150-180℃ and 10-20MPa. After demolding, the high-sealing anti-aging rubber shock-absorbing gasket is obtained.

9. The method for preparing a high-sealing, anti-aging rubber damping washer according to claim 8, characterized in that, The number of times the thin-walled triangular package is punched is 6, and the roller gap is 0.5-1.0mm.

10. The method for preparing a high-sealing, anti-aging rubber damping washer according to claim 8, characterized in that, Steps (1) and (2) are performed under a nitrogen atmosphere.

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