Damping rubber materials, their preparation methods and applications

Abstract

This application discloses a damping rubber material that can achieve stable vibration reduction effect in a wide operating temperature range (-25℃ to 70℃), including extreme environments, by hot-pressing a damping rubber composition containing a specified amount of nitrile rubber, resin-based vulcanizing agent, plasticizer, reinforcing filler, and anti-aging agent, and provides a method for preparing the damping rubber material and its application.

Description

Technical Field

[0001] This invention relates to damping rubber materials, their preparation methods, and their uses. Background Technology

[0002] With the rapid development of modern industry, reducing vibration and noise has become a crucial issue in various fields. Vibration not only reduces operational accuracy and affects product quality, but may also shorten product lifespan or jeopardize safety. The application of damping materials can dissipate the energy of mechanical waves, thereby mitigating the harm they cause. In particular, high-damping materials play a key role in vibration control and energy absorption in fields such as vehicle vibration reduction, engineering vibration damping, and protection of precision instruments and their components. Therefore, researching and mastering vibration control technology and developing damping materials (such as vibration-damping rubber) adapted to industrial development has become a major technical challenge facing various fields.

[0003] The elastomer materials commonly used in vibration damping rubbers mainly include the following: natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene propylene diene monomer (EPDM), and butyl rubber (IIR). The influence of elastomer materials on vibration damping characteristics is considered from the perspective of rubber formulation. Besides the selection of rubber components, appropriate vulcanizing agents, fillers (such as carbon black and silica), and additives also need to be chosen.

[0004] Vulcanization is a mature process with many years of history. However, it generates harmful sulfur-containing compounds during processing. Furthermore, rubber products cannot be incinerated at high temperatures after their lifespan, as the sulfur will inevitably turn into harmful gases or toxic residues. Adjusting the vulcanization system, increasing the type and content of fillers, and introducing additives such as antioxidants can significantly improve the fatigue life of rubber. The use of high-performance vulcanizing agents can shorten vulcanization time, reduce the amount of vulcanizing agent used, and increase crosslinking density, thereby enhancing fatigue resistance.

[0005] Generally, environmental factors such as temperature, humidity, and oxygen content all affect the fatigue properties of rubber. High temperatures intensify the movement of rubber molecular chains, easily leading to stress relaxation and aging; low temperatures cause rubber to harden, reduce toughness, and become brittle. To date, various studies have been conducted to reduce vibration in areas such as vehicle vibration damping, engineering vibration control, and protection of precision instrument components. However, with the continuous development of industry, in addition to daily use, there are more complex application scenarios such as underwater, high-altitude, and fire scenes. Research on the vibration damping characteristics of vibration-damping rubber in extreme working environments is still incomplete.

[0006] For example, Patent Document 1 relates to the field of vibration reduction technology for electric generators. Through improved formulations and preparation methods, the resulting product exhibits excellent mechanical properties and is wear-resistant and aging-resistant. This vibration damping pad for electric generators is made from the following raw materials in parts by weight: 50-60 parts nitrile rubber, 40-50 parts polyurethane rubber, 2-3 parts stearic acid, 2-3 parts dioctyl adipic acid, 4-6 parts zinc oxide, 1-2 parts glass fiber, 8-12 parts calcined clay, 8-12 parts microcrystalline cellulose, 8-12 parts silica, 2-4 parts vulcanizing agent, 3-5 parts palm wax, 2-5 parts microcrystalline wax, and 2-4 parts antioxidant. The tensile properties and hardness, among other physical properties, of the products prepared in Examples 1-8 and Comparative Examples 1-2 under 150°C hot air aging conditions were evaluated. However, the damping characteristics under low-temperature conditions were not evaluated. Furthermore, given the relatively uniform operating environment of electric generators, this patent document did not consider the impact of extreme low-temperature environments on the vibration damping pad.

[0007] Furthermore, for example, Patent Document 2 relates to an elastomer composition with acoustic damping properties. This one-component thermosetting reactive composition consists of a liquid rubber with reactive olefinic double bonds and, as needed, a solid rubber and a sulfur-based vulcanization system. It exhibits a high acoustic dynamic loss coefficient in the vulcanized state over a wide operating temperature range, approximately +10°C to +40°C. These compositions can be used as acoustic damping adhesives, sealants, or coating materials. However, this patent document only focuses on the acoustic damping value (d-combi) and does not address the impact of extreme low-temperature environments on vibration reduction performance.

[0008] It is evident that commonly used rubber materials currently struggle to simultaneously achieve high damping performance across a wide temperature range, resulting in unstable vibration reduction performance under extreme environments and wide operating temperature ranges (e.g., high temperatures up to 70℃ and low temperatures down to -25℃). Therefore, designing and fabricating a high-damping rubber material that maintains a damping loss factor greater than 0.5 within the temperature range of -25℃ to 70℃ has become an urgent problem to be solved in this field.

[0009] Existing technical documents

[0010] Patent Document 1: CN 108794834 B

[0011] Patent Document 2: JP Patent No. 10-509755 Summary of the Invention

[0012] The technical problem that the invention aims to solve

[0013] As mentioned above, none of the technologies disclosed in the aforementioned patent documents consider stable vibration reduction effects over a wide operating temperature range (e.g., high temperatures up to 70°C and low temperatures down to -25°C). Therefore, the technical problem to be solved by this invention is to provide a damping rubber material formed from a damping rubber composition that can achieve stable vibration reduction effects over a wide operating temperature range, including extreme environments, as well as its preparation method and applications.

[0014] Solutions for solving technical problems

[0015] The inventors of this application, in view of the aforementioned technical problems, have been working diligently to find that the aforementioned technical problems can be solved by using specific amounts of nitrile rubber, vulcanizing agents, etc.

[0016] That is, the present invention relates to the following technical solutions.

[0017] This invention provides a damping rubber material, characterized in that:

[0018] It is a damping rubber material obtained by hot-pressing vulcanization of a damping rubber composition with nitrile rubber as the main rubber component.

[0019] The acrylonitrile (ACN) content in the nitrile rubber is greater than 30% and less than 60% by percentage, and the Mooney viscosity of the nitrile rubber is greater than 60 and less than 120.

[0020] The damping rubber composition also includes a vulcanizing agent, a plasticizer, a reinforcing filler, and an anti-aging agent.

[0021] The vulcanizing agent is selected from one or more of sulfur, organic peroxides, quinone oxime compounds, and resin-based vulcanizing agents.

[0022] The plasticizer is selected from one or more of ester plasticizers and petroleum resins, wherein the ester plasticizer is an ester formed by a polycarboxylic acid having two or more carboxyl groups and an alcohol having 1-20 carbon atoms.

[0023] Furthermore, the damping rubber material maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25℃ to 70℃.

[0024] According to an embodiment of the present invention, the content of rubber component in the damping rubber composition is 40-90% by weight.

[0025] According to an embodiment of the present invention, the content of the vulcanizing agent in the damping rubber composition is 1-30 parts by weight per 100 parts by weight of the rubber component.

[0026] According to an embodiment of the present invention, the content of plasticizer in the damping rubber composition is 1-20 parts by weight per 100 parts by weight of rubber component.

[0027] According to an embodiment of the present invention, the content of reinforcing filler in the damping rubber composition is 1-50 parts by weight per 100 parts by weight of rubber component.

[0028] According to an embodiment of the present invention, the content of the anti-aging agent in the damping rubber composition is 10-60 parts by weight per 100 parts by weight of the rubber component.

[0029] According to an embodiment of the present invention, the reinforcing filler is an inorganic reinforcing filler, and the particle size of the inorganic reinforcing filler is 1-100 micrometers.

[0030] This invention provides a method for preparing the damping rubber material, comprising a mixing step of compounding the damping rubber composition and a hot-pressing vulcanization step of hot-pressing the obtained compound, characterized in that...

[0031] In the mixing process, nitrile rubber is plasticized 1-3 times in a mixer at room temperature, then an anti-aging agent is added and mixed evenly. Plasticizer, reinforcing filler, vulcanizing agent, and other additives as needed are then added to the rubber compound and mixed evenly to obtain the compounded rubber.

[0032] In the hot-press vulcanization process, the compound obtained in the mixing process is hot-press vulcanized for 10 to 40 minutes at a vulcanization temperature of 120-200℃ and a pressure of 3-15MPa.

[0033] According to an embodiment of the present invention, hot-press vulcanization is carried out for 15 to 30 minutes at a vulcanization temperature of 150-180°C and a pressure of 5-10 MPa.

[0034] This invention provides the use of the aforementioned damping rubber material in vehicle vibration damping devices, building vibration isolation systems, electronic equipment protective components, and vibration isolation of precision instrument components.

[0035] Invention Effects

[0036] According to the technical solution of the present invention, a damping rubber material that achieves stable vibration reduction effect over a wide operating temperature range, including extreme environments, can be provided. Furthermore, the damping rubber material of the present invention has excellent processing performance, can be industrially produced using conventional equipment, and is both cost-controllable and repeatable. Detailed Implementation

[0037] The present invention is further illustrated below by way of embodiments, but it should be understood that these specific examples are not intended to limit the scope of the invention in any way. It should be noted that, unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and their quality meets national standards. Unless otherwise specified in the present invention, content refers to weight percentage or weight ratio.

[0038] Damping rubber materials

[0039] The damping rubber material of the present invention is a hot-pressed vulcanized crosslinked rubber composition containing nitrile rubber (NBR) as the main rubber component, comprising 1-30 parts by weight of vulcanizing agent, 1-20 parts by weight of plasticizer, 1-50 parts by weight of reinforcing filler, and 10-60 parts by weight of anti-aging agent relative to 100 parts by weight of the rubber component. The acrylonitrile (ACN) content of the NBR is greater than 30% and less than 60%, and the Mooney viscosity is greater than 60 and less than 120. The vulcanizing agent is selected from one or more of sulfur, organic peroxides, quinone oxime compounds, and resin-based vulcanizing agents. The plasticizer is selected from one or more of ester plasticizers, petroleum resins, etc., wherein the ester plasticizer is an ester formed by a polycarboxylic acid having two or more carboxyl groups and an alcohol having 1-20 carbon atoms. Furthermore, the damping rubber material maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25°C to 70°C. The damping rubber material according to the present invention can achieve stable vibration reduction performance over a wide operating temperature range, including extreme environments.

[0040] <Rubber Composition>

[0041] The damping mechanism of rubber materials stems from the energy dissipation caused by intermolecular friction when molecular chains move under alternating stress. Nitrile butadiene rubber (NBR), with its high tanδ due to its numerous side methyl groups and polar side groups, exhibits excellent damping performance and is widely used in vibration damping materials. However, generally, single rubbers have very low damping factors, narrow glass transition temperatures (Tg), and limited effective damping temperature ranges. Therefore, it is difficult to prepare high-performance damping materials using only a single rubber; typically, blending with other rubber materials is necessary to improve the material's damping performance.

[0042] This invention, through dedicated research, has achieved a high-damping material formed by blending nitrile rubber as the main rubber component with a specific vulcanizing agent and incorporating specific anti-aging agents and other components via hot-press vulcanization. Furthermore, due to the excellent compatibility of the components in this invention, superior damping performance can be achieved over a wide temperature range, a surprising achievement in the field. In this invention, using nitrile rubber as the main rubber component means that the content of nitrile rubber in the rubber component is 50% or more by weight, preferably 60% or more, more preferably 65% ​​or more, more preferably 80% or 90% or more. In the most preferred embodiment of this application, the rubber component consists solely of nitrile rubber.

[0043] Nitrile butadiene rubber (NBR) is a copolymer polymerized from acrylonitrile and butadiene monomers. The acrylonitrile content in NBR affects its polarity, chain flexibility, interchain interactions, and the content of double bonds within the molecular chain. The NBR used in this invention has an acrylonitrile (ACN) content greater than 30% and less than 60% (by weight), preferably greater than 31% and less than 50%, and most preferably less than 45%.

[0044] By using the acrylonitrile rubber specified in this invention, good processability can be achieved, and excellent cold resistance can be maintained. Even in cold environments as low as -25°C, the damping loss factor of the damping rubber material can still be maintained.

[0045] The Mooney viscosity of the nitrile rubber of the present invention is greater than 60 and less than 120, preferably greater than 72 and less than 105, and most preferably less than 100.

[0046] By using the nitrile rubber with the Mooney viscosity specified in this invention, good moldability can be achieved, making it suitable for a wider range of applications. Furthermore, it maintains excellent heat and cold resistance.

[0047] In this invention, the damping rubber composition obtained by hot-press vulcanization crosslinking has a rubber component of 40-90% by weight, preferably 45-80%, and more preferably 48-70%.

[0048] <Vulcanizing Agent>

[0049] Vulcanizing agents are substances that enable rubber to undergo vulcanization (crosslinking). They are broadly classified into inorganic and organic categories. Inorganic vulcanizing agents include sulfur, sulfur monochloride, selenium, tellurium, etc. Organic vulcanizing agents include organic peroxides (such as benzoyl peroxide), quinone oxime compounds, resin-based vulcanizing agents, etc. Inorganic vulcanizing agents containing excessive amounts of elemental sulfur and sulfur-containing compounds have adverse environmental pollution characteristics, such as the emission of harmful gases.

[0050] The present invention uses a vulcanizing agent selected from one or more of sulfur, organic peroxides, quinone oxime compounds, and resin-based vulcanizing agents, preferably containing resin-based vulcanizing agents. By forming C-C bonds and ether bonds with high thermal stability, the heat resistance and other properties of vulcanized rubber can be improved.

[0051] In the vulcanization process of nitrile rubber, the peroxide vulcanization system can produce rubber compounds with low compression set, fast vulcanization speed, and resistance to hot air aging. This invention can use commonly used peroxide vulcanizing agents, such as alkyl peroxides, diacyl peroxides (benzoyl peroxide (BPO)), and peroxide esters. Specific peroxide vulcanizing agents include dicumyl peroxide (DCP) and 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane.

[0052] When used as a quinone oxime compound vulcanizing agent in the vulcanization of nitrile butadiene rubber, it can achieve better physical and mechanical properties, especially better heat aging resistance. Specifically, p-benzoquinone dioxime, etc., can be used.

[0053] As a resin-based vulcanizing agent, one or more of phenolic resin-based vulcanizing agents are preferred, and one or more of phenol-formaldehyde resins are more preferred. Examples of phenol-formaldehyde resins include unsubstituted phenol-formaldehyde resins and alkyl-substituted phenol-formaldehyde resins (alkyl groups with 1-15 carbon atoms). The alkyl-substituted phenol-formaldehyde resin may have 1-3 alkyl groups as substituents, and the alkyl groups may be substituted with halogens (alkyl groups with 1-15 carbon atoms). As a resin-based vulcanizing agent, better physical and mechanical properties can be obtained, especially better heat aging resistance.

[0054] The amount of vulcanizing agent used in the damping rubber composition of the present invention is 1-30 parts by weight based on 100 parts by weight of rubber component, preferably 2-28 parts by weight, more preferably 5-27 parts by weight, and most preferably 10-25 parts by weight.

[0055] <Plasticizer>

[0056] The use of plasticizers can significantly improve the mixing performance and molding properties of NBR during processing, such as calendering, extrusion, and injection molding. Plasticizers can also improve polymer processing performance and tensile properties; reduce viscosity, lower hardness and modulus, increase flowability, and improve cold resistance. This invention uses plasticizers selected from one or more of ester plasticizers and petroleum resins. By adding plasticizers, the intermolecular forces of NBR can be weakened, thereby lowering the rubber's Tg, making it easier to perform calendering, extrusion molding, and other operations. Simultaneously, in synergy with vulcanizing agents, NBR is endowed with higher elasticity, lower heat generation, and improved cold resistance.

[0057] The ester plasticizer is preferably selected from one or more esters formed by polycarboxylic acids having two or more carboxyl groups and alcohols having 1-20 carbon atoms.

[0058] Examples of ester plasticizers include ester plasticizers formed from phthalic acid and alcohols with 1-20 carbon atoms, and fatty acid esters formed from fatty acids with two or more carboxyl groups and alcohols with 1-20 carbon atoms.

[0059] The phthalate plasticizers described herein possess excellent compatibility and plasticizing effects. The phthalate plasticizers are selected from one or more of dibutyl phthalate (DBP), dioctyl phthalate, etc. The fatty acid ester plasticizers are selected from one or more of dioctyl sebacate, diisooctyl sebacate, di-n-hexyl sebacate, di-n-butyl sebacate, etc.

[0060] Petroleum resins have good plasticizing effects and processing performance, and can improve the hardness, wear resistance and weather resistance of products.

[0061] The amount of plasticizer used in the damping rubber composition of the present invention is 1-20 parts by weight, preferably 5-18 parts by weight, and more preferably 6-15 parts by weight, based on 100 parts by weight of the rubber component.

[0062] <Reinforcing Filler>

[0063] The damping coefficient and modulus of reinforcing fillers are closely related to those of nitrile rubber. During deformation, internal friction between macromolecular chain segments and fillers, as well as between fillers themselves, will cause changes in the damping properties of the vulcanizate. The particle size and other morphological properties of the fillers will also affect the damping performance.

[0064] The reinforcing filler of this invention is preferably an inorganic reinforcing filler, which is selected from one or more of the following: clay, calcium carbonate, magnesium carbonate, alumina, talc, mica powder, graphite, carbon black, and silica. For example, hard clay is inexpensive and has a significant reinforcing effect. Alumina containing water is an excellent reinforcing filler for heat-resistant formulations of nitrile rubber.

[0065] Among them, silica, or amorphous silica, is a white, non-toxic fine powder with excellent properties such as porosity, high dispersibility, light weight, good chemical stability, and high temperature resistance. Silica is an effective reinforcing filler for NBR, effectively improving the tensile strength and tear strength of the vulcanizate. However, it is generally believed that using carbon black and silica to reinforce NBR also affects its heat resistance. This invention breaks through this technical understanding.

[0066] The inorganic reinforcing filler of the present invention has a particle size of 1-100 micrometers, preferably 1-80 micrometers, and more preferably 1-60 micrometers.

[0067] The amount of reinforcing filler used in the damping rubber composition of the present invention is 1-50 parts by weight, preferably 5-40 parts by weight, and more preferably 8-30 parts by weight, based on 100 parts by weight of the rubber component.

[0068] Anti-aging agents

[0069] NBR is prone to thermo-oxidative aging during use due to changes in environmental factors such as heat, oxygen, light, and water. This leads to a decline in mechanical and physicochemical properties, affecting the performance of the finished product. When rubber ages, its molecular chains continuously degrade and cross-link. If the decomposition rate is too high, the molecular weight of the rubber will decrease, resulting in sticky products and reduced strength. Conversely, the surface will harden and lose elasticity. Adding antioxidants to the rubber can delay aging.

[0070] The anti-aging agent used in this application is selected from one or more of the following: phenols, polydihydroquinolines, amines, and imidazoles.

[0071] Among them, one or more of the following are preferred: hindered phenols, bisphenol hindered phenols, triphenol hindered phenols, hydroquinone, polydihydroquinoline, diphenylamine, p-phenylenediamine, mercaptobenzimidazole and their salts.

[0072] Specific anti-aging agents include one or more of the following: hindered phenol AO60, hindered phenol AO-70, hindered phenol AO-80, bisphenol hindered phenol 2246, triphenol-type hindered phenol 3114, 3125, 330, 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (4020), N-cyclohexyl-N'-phenyl-p-phenylenediamine (4010), 2-mercaptobenzimidazole (MB), and 2-mercaptobenzimidazole zinc salt (MBZ).

[0073] The amount of anti-aging agent used in the damping rubber composition of the present invention is 10-60 parts by weight based on 100 parts by weight of rubber component, preferably 20-60 parts by weight, more preferably 25-55 parts by weight, and most preferably 30-55 parts by weight.

[0074] <Other Additives>

[0075] In the damping rubber composition of the present invention, additives such as lubricants, vulcanization accelerators, tackifiers, and solvents conventional in the art may be added locally as needed. The amount of other additives in the damping rubber composition of the present invention is 0-20 parts by weight per 100 parts by weight of the rubber component, preferably 0.1-10 parts by weight, and more preferably 0.5-5 parts by weight.

[0076] [Preparation Method of Damping Rubber Materials]

[0077] The method for preparing the damping rubber material of the present invention includes a process of mixing nitrile rubber, vulcanizing agent, plasticizer, reinforcing filler and anti-aging agent in a formula ratio, and a process of hot-pressing and vulcanizing the obtained compound at a specified temperature.

[0078] <Mixing Process>

[0079] Damping rubber materials are usually mixed by methods such as casting and mixing. The rubber mixing machine of the present invention includes open mill, internal mixer, etc.

[0080] In the mixing process of this invention, nitrile rubber is added to a mixer at room temperature and plasticized 1-3 times. Then, an anti-aging agent is added and mixed evenly. Plasticizer, reinforcing filler, vulcanizing agent and other additives as needed are added to the rubber compound and mixed evenly to obtain nitrile rubber compound.

[0081] <Pressure vulcanization process>

[0082] The nitrile rubber compound obtained from the mixing process is hot-pressed at a vulcanization temperature of 120-200℃ and a pressure of 3-15MPa for 10-40 minutes. Vulcanization temperature is a fundamental condition for the vulcanization reaction of rubber; higher vulcanization temperatures result in faster vulcanization and higher production efficiency. Conversely, lower temperatures lead to slower vulcanization and lower production efficiency. If the temperature exceeds 200℃, the high-temperature rubber molecular chains will break down, leading to vulcanization reversion. If the temperature is below 120℃, the vulcanization reaction efficiency decreases. The preferred vulcanization temperature is 130-180℃, more preferably 140-170℃. The preferred pressure is 4-12MPa, more preferably 6-9MPa. The preferred vulcanization time is 15-30 minutes, more preferably 15-25 minutes.

[0083] The damping rubber material of the present invention maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25°C to 70°C.

[0084] Example

[0085] The present invention will be described in more detail below by way of examples and comparative examples, but the present invention is not limited to these examples.

[0086] <Nitrile rubber>

[0087] Nitrile rubber 1: (NBR3308, acrylonitrile content 32%-35%, Mooney viscosity 75-85, manufacturer: Lanzhou Chemical Industry Co., Ltd.)

[0088] Nitrile rubber 2 (NBR3606, acrylonitrile content 36%-40%, Mooney viscosity 65-80, manufacturer: Lanzhou Chemical)

[0089] Nitrile rubber 3: (NBR1704 acrylonitrile content 17-20%, Mooney viscosity 40-65, manufacturer: Lanzhou Chemical)

[0090] Nitrile rubber 4: (trade name: Russian 2665, acrylonitrile content 27%–30%, Mooney viscosity 60–70)

[0091] <Vulcanizing Agent>

[0092] Sulfur (powder, Luoyang Tianzhidao New Material Technology Co., Ltd.)

[0093] Dicumyl peroxide (DCP, Xiangyun Chemical)

[0094] Resin vulcanizing agent 1: (Phenolic resin, Hebei Zetian Chemical Co., Ltd.)

[0095] Resin vulcanizing agent 2: (SP1045, Lianhui Chemical)

[0096] <Plasticizer>

[0097] DMP (Dimethyl Phthalate, Shanghai Huafutai Chemical Co., Ltd.)

[0098] DBP: (Dibutyl Phthalate, Shandong Yousuo Chemical Technology Co., Ltd.)

[0099] DOS: (Dioctyl sebacate, Tianyuan Aviation Materials (Yingkou) Technology Co., Ltd.)

[0100] <Reinforcing Filler>

[0101] Silica 1 (particle size: 48 microns, Shanghai Puni Industrial Co., Ltd.)

[0102] Silica 2 (Particle size: 1.6 microns, Hengtai Plastic Raw Materials Co., Ltd.)

[0103] Silica 3 (particle size: 0.5 microns, Jinan Delan Chemical Co., Ltd.)

[0104] Anti-aging agents

[0105] Hindered phenol AO60 (Shanghai Kaiyin Chemical)

[0106] Bisphenol-hindered phenol 2246 (Guangzhou Yuanda)

[0107] Triphenol-type hindered phenol 3114 (Shanghai Boyer Chemical Co., Ltd.)

[0108] 2,2,4-Trimethyl-1,2-Dihydroquinoline Polymer (RD) (Shandong Yousuo Chemical Technology Co., Ltd.)

[0109] 2-Mercaptobenzimidazole (MB) (Zhejiang Huangyan Zhedong Rubber Additives Co., Ltd.)

[0110] N-(1,3-Dimethylbutyl)-N'-Phenylene-p-phenylenediamine (4020) (Shijiazhuang Anhui Chemical Technology Co., Ltd.)

[0111] N-Cyclohexyl-N'-Phenylene-p-phenylenediamine (4010) (Shandong Yousuo Chemical Technology Co., Ltd.)

[0112] <Determination Method>

[0113] In characterizing the damping performance of elastomers, the tangent of the phase angle δ (also known as the mechanical loss angle) between strain lag and stress is generally used as the damping factor to describe the magnitude of the material's internal friction. The magnitude of the internal friction of an elastomer material can be expressed as:

[0114]

[0115] In the formula: E″ represents the loss modulus, and E′ represents the energy storage modulus.

[0116] This invention utilizes a MAK-04 viscoelastic spectrometer manufactured by Metravib, France. A vertical load of 50 N is applied, and the displacement and load are reset to zero. The vibration frequency is then preloaded to 125 Hz, with an excitation amplitude of ±50 μm. The dynamic testing machine employs a single-point testing method and automatically records the sample's damping loss factor (tanδ). Refer to GJB981-1990 for details.

[0117] Example 1

[0118] Prepare the raw materials according to the formula shown in Table 1. Prepare 100g nitrile rubber, 2g sulfur, 20g resin vulcanizing agent 1, 10g DMP, 15g silica 1, 45g AO60, and 5g anti-aging agent 4010.

[0119] In the mixing process, the nitrile rubber is plasticized three times on a two-roll mill at room temperature, then wrapped around the rolls, and an anti-aging agent is added and mixed three more times to make the rubber compound uniform. The rubber compound is then wrapped around the rolls again, and plasticizers, reinforcing fillers, and vulcanizing agents are added to the rubber compound. The rubber compound is then mixed uniformly by alternating the use of a figure-eight cutter and a triangular wrapping thin passer (three times each). The roll gap is then increased and the rubber is sheeted to obtain the nitrile rubber compound.

[0120] After the components were mixed evenly, the mixture was hot-pressed and vulcanized at 160℃ and 8MPa for 20 minutes to obtain the damping rubber material. A cylindrical damping rubber material with a diameter of 5mm and a height of 10mm was used as a test sample and tested according to the above test method. The results showed that the loss factor of the material was above 0.53 in the temperature range of -25℃ to 70℃.

[0121] Examples 2-4

[0122] In addition to preparing each raw material according to the adjusted formula in Table 1 (100g of nitrile rubber, and other components weighed according to the weight ratio or weight percentage shown in the table), the mixture was mixed and hot-pressed vulcanized in the same way as in Example 1, and the tests were carried out in the same way. The results are shown in Table 1.

[0123] Comparative Examples 1-4

[0124] In addition to preparing each raw material according to the adjusted formula in Table 1 (100g of nitrile rubber, and weighing other components according to the weight ratio or weight percentage shown in the table), the mixture was mixed according to the mixing method in Example 1 and then hot-pressed and vulcanized.

[0125] The composition of the damping rubber compositions of Examples 1-4 and Comparative Examples 1-4, and the determination results of the obtained damping rubber materials are shown in Table 1 below. All components are expressed in parts by weight or weight percentages.

[0126] Table 1

[0127]

[0128]

[0129] Example 5

[0130] The nitrile rubber compound prepared in Example 1 was hot-pressed and vulcanized at 150°C and 9 MPa for 20 minutes. Tests were performed according to the above-described test methods.

[0131] Example 6

[0132] The nitrile rubber compound prepared in Example 1 was hot-pressed and vulcanized at 170°C and 6 MPa for 15 minutes. Tests were performed according to the above-described test methods.

[0133] Example 7

[0134] The nitrile rubber compound prepared in Example 1 was hot-pressed and vulcanized at 140°C and 9 MPa for 25 minutes. Tests were performed according to the above-described test methods.

[0135] Test results show that the damping loss factors of the damping rubber materials in Examples 5 to 7 are above 0.51, above 0.53, and above 0.50, respectively, at temperatures ranging from -25℃ to 70℃.

[0136] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, shall still fall within the protection scope of the present invention.

[0137] Industrial applications

[0138] The high-damping rubber material described in this invention can be applied to vehicle vibration damping devices, building vibration isolation systems, electronic equipment protective components, and vibration damping for precision instrument components. Its manufacturing process is simple, requiring only minor modifications to existing production lines to achieve industrial-scale production, resulting in significant economic benefits and widespread application value.

Claims

1. A damping rubber material, characterized in that: It is a damping rubber material obtained by hot-pressing vulcanization of a damping rubber composition with nitrile rubber as the main rubber component, wherein the rubber component consists only of nitrile rubber. The acrylonitrile (ACN) content in the nitrile rubber is greater than 30% and less than 60% by percentage, and the Mooney viscosity of the nitrile rubber is greater than 60 and less than 120. The damping rubber composition also includes a vulcanizing agent, a plasticizer, a reinforcing filler, and an anti-aging agent. The vulcanizing agent is a combination of a phenolic resin vulcanizing agent and a vulcanizing agent selected from sulfur and dicumyl peroxide (DCP). The plasticizer is an ester plasticizer, which is an ester formed by a polycarboxylic acid having two or more carboxyl groups and an alcohol having 1-20 carbon atoms. The anti-aging agent is a combination of hindered phenol and one selected from polydihydroquinoline, amine, and imidazole derivatives. The rubber component in the damping rubber composition comprises 40-90% by weight. The content of the vulcanizing agent in the damping rubber composition is 20-25 parts by weight per 100 parts by weight of the rubber component. The plasticizer content in the damping rubber composition is 10-12 parts by weight per 100 parts by weight of the rubber component. The content of reinforcing filler in the damping rubber composition is 15-20 parts by weight per 100 parts by weight of rubber component. The content of the anti-aging agent is 36-51 parts by weight per 100 parts by weight of the rubber component. The reinforcing filler is silica, and the particle size of the reinforcing filler is 1.6-48 micrometers. Furthermore, the damping rubber material maintains a damping loss factor of 0.5 or higher at temperatures ranging from -25℃ to 70℃.

2. The damping rubber material as described in claim 1, wherein, The rubber component in the damping rubber composition is 45-80% by weight.

3. A method for preparing the damping rubber material according to claim 1 or 2, comprising a mixing step of compounding the damping rubber composition and a hot-pressing vulcanization step of hot-pressing the obtained compound, characterized in that, In the mixing process, nitrile rubber is plasticized 1-3 times in a mixer at room temperature, then an anti-aging agent is added and mixed evenly. Plasticizer, reinforcing filler, vulcanizing agent, and other additives as needed are then added to the rubber compound and mixed evenly to obtain the compounded rubber. In the hot-press vulcanization process, the compound obtained in the mixing process is hot-press vulcanized for 10-40 minutes at a vulcanization temperature of 120-200℃ and a pressure of 3-15MPa.

4. The method for preparing the damping rubber material according to claim 3, wherein, Hot-press vulcanization is carried out for 15-30 minutes at a vulcanization temperature of 150-180℃ and a pressure of 5-10MPa.

5. The use of the damping rubber material according to claim 1 or 2 in vehicle vibration damping devices, building vibration isolation systems, electronic equipment protective components, and vibration isolation of precision instrument components.

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