Corrosion-resistant ethylene-propylene rubber sound-absorbing noise reduction material and preparation method thereof

Abstract

The application discloses a kind of corrosion-resistant ethylene-propylene rubber sound-absorbing noise reduction materials, specifically relates to EPDM material technical field, including the following raw materials: ethylene-propylene rubber raw rubber, modified corrosion-resistant filler, composite foaming agent, crosslinking agent, activator, anti-aging additive, dispersing lubricant, toughening modifier.The super strong corrosion resistance of the application is suitable for harsh working conditions: dense protective structure is constructed by silane modified composite filler, effectively blocks acid, alkali, salt fog, oil stain, chemical waste gas erosion, material has no swelling, pulverization, cracking phenomenon in acid and alkali solution, high salt fog environment, corrosion resistance is increased by more than 60%, completely solve the corrosion failure problem of traditional material, macropore+micropore composite pore structure, perfect adaptation 200-4000Hz full-band noise absorption, low-frequency noise reduction effect is increased by more than 45%, mid-high frequency noise reduction efficiency is stably above 85%;And pore structure strength is high, not easy to collapse and block, long-term use noise reduction performance attenuation rate is less than 5%.

Description

Technical Field

[0001] This invention relates to the field of ethylene propylene rubber materials technology, and more specifically, to a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material and its preparation method. Background Technology

[0002] Ethylene propylene diene monomer (EPDM) rubber possesses excellent elasticity, aging resistance, insulation, and moldability, and its porous internal structure makes it a mainstream sound-absorbing and noise-reducing polymer material in the industrial field. Conventional EPDM sound-absorbing materials, thanks to their porous microporous structure, can effectively absorb mid-to-high frequency noise through air-damped vibration and microporous friction loss of sound wave energy. They are widely used in noise reduction treatments for machinery, rail transportation, building walls, and ventilation ducts.

[0003] Currently, conventional EPDM noise reduction materials on the market have simple preparation processes, mostly employing a single foaming modification method. They achieve noise reduction by forming a porous structure through simple physical foaming, resulting in low cost and convenient processing. They are widely used in normal, dry, ambient, and non-corrosive working conditions. However, existing conventional EPDM sound-absorbing and noise-reducing materials have significant performance shortcomings in complex industrial applications. Specific defects are as follows:

[0004] 1. Poor corrosion resistance and short service life: Conventional EPDM modification systems only optimize basic mechanical properties and do not address modifications for environments with acid and alkali corrosion, salt spray, damp oil stains, or corrosive chemical exhaust gases. In chemical plant areas, coastal high-salt-spray environments, humid industrial workshops, and environments surrounding acid and alkali spray equipment, materials are prone to swelling, cracking, pulverization, and micropore collapse, losing structural stability in a short period, rapidly failing their noise reduction function, requiring frequent replacements, and resulting in high maintenance costs.

[0005] 2. Insufficient noise reduction stability: Conventional foamed EPDM materials have a simple pore structure and uneven pore size distribution, making it difficult to accurately control the open porosity. This results in extremely poor absorption of low-frequency noise and makes them only suitable for single medium- to high-frequency noise scenarios. Furthermore, after the material is corroded and aged, the microporous structure is prone to collapse and blockage, leading to a significant decrease in noise reduction performance and an inability to maintain a stable noise reduction effect over a long period.

[0006] 3. Weak overall mechanical properties: Ordinary modified EPDM noise reduction materials have low hardness and poor resistance to compression deformation. They are prone to permanent deformation after long-term pressure or environmental erosion, which damages the structural integrity. They cannot adapt to the complex and harsh working conditions of long-term exposure to sunlight, corrosion and vibration outdoors, and their application scenarios are severely limited.

[0007] 4. Poor adaptability of preparation process: Existing preparation process formulas are simple and modification processes are simple, which cannot simultaneously achieve corrosion resistance modification, precise pore control and structural reinforcement integrated processing. It is difficult to take into account the material's corrosion resistance, noise reduction performance and mechanical stability, and cannot meet the long-term noise reduction requirements of high-end industrial corrosion conditions.

[0008] In summary, the market currently lacks an ethylene propylene rubber noise reduction material that combines strong corrosion resistance, noise reduction across high and low frequencies, structural stability, aging resistance, and long service life, along with a matching efficient preparation process. Summary of the Invention

[0009] To address the shortcomings of existing conventional ethylene propylene rubber sound-absorbing and noise-reducing materials, such as weak corrosion resistance, poor noise reduction stability under harsh working conditions, insufficient mechanical properties, and limited applicability, this invention aims to provide a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material and its preparation method.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material, comprising the following raw materials in parts by weight: 60-75 parts of ethylene propylene rubber raw rubber, 15-22 parts of modified corrosion-resistant filler, 4-8 parts of composite foaming agent, 2-4 parts of crosslinking agent, 1.5-3 parts of activator, 1-2.5 parts of anti-aging additive, 0.8-1.8 parts of dispersing lubricant, and 3-6 parts of toughening modifier.

[0011] In a preferred embodiment, the raw materials include the following parts by weight: 65-70 parts of ethylene propylene rubber raw rubber, 17-20 parts of modified corrosion-resistant filler, 5-7 parts of composite foaming agent, 2.5-3.5 parts of crosslinking agent, 2-2.5 parts of activator, 1.5-2 parts of anti-aging additive, 1.2-1.4 parts of dispersing lubricant, and 4-5 parts of toughening modifier.

[0012] In a preferred embodiment, the raw materials include the following parts by weight: 68 parts of ethylene propylene rubber raw rubber, 18 parts of modified corrosion-resistant filler, 6 parts of composite foaming agent, 3 parts of crosslinking agent, 2.3 parts of activator, 1.8 parts of anti-aging agent, 1.3 parts of dispersing lubricant, and 4.5 parts of toughening modifier.

[0013] In a preferred embodiment, the ethylene propylene rubber raw material is selected from EPDM rubber, with an ethylene content of 45%-55% and a Mooney viscosity of 60-80. The crosslinking agent is selected from dicumyl peroxide. The aging resistant additive is a compound of antioxidant 1010 and ultraviolet absorber UV-531. The toughening modifier is selected from polyolefin elastomer.

[0014] In a preferred embodiment, the modified corrosion-resistant filler is a compound of silane coupling agent-modified talc powder and nano-silica, and the mass ratio of talc powder to nano-silica is 3:1.

[0015] In a preferred embodiment, the composite foaming agent is a composite foaming system of azodicarbonamide and sodium bicarbonate, and the mass ratio of azodicarbonamide to sodium bicarbonate is 2:1.

[0016] This invention also provides a method for preparing a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material, comprising the following steps:

[0017] Step 1: Raw material pretreatment. Place the modified corrosion-resistant filler in an oven at 80-90℃ and dry for 2-3 hours to remove moisture and impurities; crush the ethylene propylene rubber raw rubber into rubber blocks for later use.

[0018] Step 2: Internal mixing. The pretreated ethylene propylene rubber blocks are fed into an internal mixer and heated to 90-100℃ for 5-8 minutes to fully melt the rubber compound. Then, toughening modifier, dispersing lubricant, and modified corrosion-resistant filler are added sequentially, and the mixture is mixed for 4-6 minutes. Finally, crosslinking agent, composite foaming agent, and aging-resistant additives are added, and the mixture is low-temperature mixed for 3-5 minutes to ensure uniform dispersion of all components without agglomeration or clumping. The resulting compound is then discharged.

[0019] Step 3: Thin sheeting. Feed the mixed rubber into the open mill, control the roller gap at 2-4mm, and thin sheet 3-5 times at room temperature to produce a uniform rubber sheet with a thickness of 3-5mm, thus eliminating the internal stress of the rubber compound.

[0020] Step 4: Segmented preheating treatment. Place the film in the oven for segmented preheating treatment.

[0021] Step 5: Gradient foaming and crosslinking. Place the preheated film in the mold of the flat vulcanizing machine and use a gradient heating foaming and crosslinking process for crosslinking and curing.

[0022] Step Six: Cooling, Shaping, and Cutting. After vulcanization, maintain pressure and allow to cool naturally to room temperature. Demold to obtain modified rubber substrate. Cut and trim according to usage requirements to obtain corrosion-resistant, high sound-absorbing, and noise-reducing ethylene propylene rubber material.

[0023] In a preferred embodiment, during the segmented preheating process in step four, the first segment is preheated at 60°C for 15 minutes, and the second segment is preheated at 80°C for 10 minutes.

[0024] In a preferred embodiment, during the gradient heating foaming crosslinking in step five, the initial temperature is 110°C, the pressure is 5MPa, and the holding time is 8 minutes, followed by heating to 135°C and holding at 8MPa for 12 minutes.

[0025] The technical effects and advantages of this invention are as follows:

[0026] 1. This invention has superior corrosion resistance and is suitable for harsh working conditions: By constructing a dense protective structure through silane-modified composite filler, it effectively blocks the corrosion of acids, alkalis, salt spray, oil stains, and chemical waste gases. The material does not swell, pulverize, or crack in acid and alkali solutions or high salt spray environments, and its corrosion resistance is improved by more than 60%, completely solving the problem of corrosion failure of traditional materials.

[0027] 2. This invention provides high-efficiency noise reduction across the entire frequency range with stable and long-lasting performance: The composite pore structure of large and micro pores perfectly adapts to noise absorption across the entire frequency band from 200-4000Hz, improving low-frequency noise reduction by more than 45% and maintaining a stable noise reduction efficiency of over 85% in the mid and high frequencies; moreover, the pore structure has high strength, is not easily collapsed or blocked, and the noise reduction performance degradation rate is less than 5% over long-term use.

[0028] 3. The present invention has excellent mechanical properties, resistance to deformation and aging: the cross-linking system and toughening filler work together to greatly improve the material’s resistance to compression deformation, tensile strength and impact resistance. It does not undergo permanent deformation under long-term pressure, vibration and sun exposure, and has extremely strong structural stability. Its service life in outdoor and industrial conditions is extended by 2-3 times.

[0029] 4. The process of this invention is highly controllable and suitable for mass production: the process parameters of segmented preheating and gradient foaming are precisely controllable, the product has uniform pores and good performance consistency, the preparation process is simple and does not require special equipment, it can be mass-produced industrially, the production cost is controllable, and the cost performance is extremely high.

[0030] 5. This invention has a wide range of applications: it can be widely used in various corrosive and harsh working conditions such as noise reduction in chemical plant areas, noise reduction of coastal equipment, sound insulation of humid vehicles, noise reduction of industrial pipelines, and sound insulation of outdoor electromechanical equipment, making up for the shortcomings of traditional noise reduction materials in terms of poor adaptability to different scenarios. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments thereof. 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.

[0032] Example 1:

[0033] This invention provides a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material, comprising the following raw materials in parts by weight: 70 parts of ethylene propylene rubber raw rubber, 18 parts of modified corrosion-resistant filler, 6 parts of composite foaming agent, 3 parts of crosslinking agent, 2 parts of activator, 1.8 parts of anti-aging additive, 1.2 parts of dispersing lubricant, and 4 parts of toughening modifier.

[0034] In a preferred embodiment, the ethylene propylene rubber raw material is selected from EPDM rubber, with an ethylene content of 45%-55% and a Mooney viscosity of 60-80. The crosslinking agent is selected from dicumyl peroxide. The aging resistant additive is a compound of antioxidant 1010 and ultraviolet absorber UV-531. Specifically, the mass ratio of antioxidant 1010 to ultraviolet absorber UV-531 is 1:1. The toughening modifier is selected from polyolefin elastomer.

[0035] In a preferred embodiment, the modified corrosion-resistant filler is a compound of silane coupling agent-modified talc powder and nano-silica, and the mass ratio of talc powder to nano-silica is 3:1.

[0036] In a preferred embodiment, the composite foaming agent is a composite foaming system of azodicarbonamide and sodium bicarbonate, and the mass ratio of azodicarbonamide to sodium bicarbonate is 2:1.

[0037] This invention also provides a method for preparing a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material, comprising the following steps:

[0038] Step 1: Raw material pretreatment. The modified corrosion-resistant filler is dried in an 85℃ oven for 2.5 hours to remove moisture and impurities. The ethylene propylene rubber raw rubber is crushed into rubber blocks for later use.

[0039] Step 2: Internal mixing. The pretreated ethylene propylene rubber blocks are put into an internal mixer and heated to 95°C for 6 minutes to fully melt the rubber compound. Then, toughening modifier, dispersing lubricant, and modified corrosion-resistant filler are added in sequence and mixed for 5 minutes. Finally, crosslinking agent, composite foaming agent, and aging-resistant additive are added and mixed at low temperature for 4 minutes to ensure that all components are evenly dispersed and there is no agglomeration or clumping. The mixed rubber is then discharged.

[0040] Step 3: Thin sheeting. The mixed rubber is fed into the open mill, with the roller gap controlled at 3mm. It is thin-passed 4 times at room temperature to produce a uniform rubber sheet with a thickness of 3mm, thus eliminating the internal stress of the rubber compound.

[0041] Step 4: Segmented preheating treatment. Place the film in the oven for segmented preheating treatment.

[0042] Step 5: Gradient foaming and crosslinking. Place the preheated film in the mold of the flat vulcanizing machine and use a gradient heating foaming and crosslinking process for crosslinking and curing.

[0043] Step Six: Cooling, Shaping, and Cutting. After vulcanization, maintain pressure and allow to cool naturally to room temperature. Demold to obtain modified rubber substrate. Cut and trim according to usage requirements to obtain corrosion-resistant, high sound-absorbing, and noise-reducing ethylene propylene rubber material.

[0044] In a preferred embodiment, during the segmented preheating process in step four, the first segment is preheated at 60°C for 15 minutes, and the second segment is preheated at 80°C for 10 minutes.

[0045] In a preferred embodiment, during the gradient heating foaming crosslinking in step five, the initial temperature is 110°C, the pressure is 5MPa, and the holding time is 8 minutes, followed by heating to 135°C and holding at 8MPa for 12 minutes.

[0046] Example 2:

[0047] Unlike Example 1, the present invention provides a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material, comprising the following raw materials in parts by weight: 65 parts of ethylene propylene rubber raw rubber, 20 parts of modified corrosion-resistant filler, 5 parts of composite foaming agent, 2.5 parts of crosslinking agent, 2.2 parts of activator, 2 parts of anti-aging additive, 1 part of dispersing lubricant, and 5 parts of toughening modifier.

[0048] Example 3:

[0049] Unlike Examples 1-2, this invention provides a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material, comprising the following raw materials in parts by weight: 72 parts of ethylene propylene rubber raw rubber, 16 parts of modified corrosion-resistant filler, 7 parts of composite foaming agent, 3.5 parts of crosslinking agent, 1.8 parts of activator, 1.5 parts of anti-aging additive, 1.5 parts of dispersing lubricant, and 3.5 parts of toughening modifier.

[0050] Commercially available EPDM noise reduction material was used as a comparative example.

[0051] The performance of the ethylene propylene rubber materials obtained in Examples 1-3 and the comparative EPDM noise reduction materials was tested. The test results are shown in Table 1.

[0052] Material porosity (%) Average noise reduction coefficient across all frequency bands Performance degradation after acid-base and salt spray corrosion tests Compression set (%) Tensile strength (MPa) Example 1 82 0.83 4.2% 3.1 12.5 Example 2 80 0.81 4.5% 3.3 13.2 Example 3 85 0.86 4.8% 3.2 12.9 Comparative Example 70 0.62 35% 12.8 10.3

[0053] Table 1

[0054] Note: Performance degradation was measured after immersion in 5% acid / alkali solution for 72 hours and salt spray for 500 hours.

[0055] As can be seen from Table 1 above, the EPDM noise reduction material produced in this embodiment of the invention has better noise reduction and corrosion resistance than commercially available EPDM noise reduction materials, and also has better mechanical properties. Therefore, this invention innovatively uses a silane-modified talc powder + nano-silica composite corrosion-resistant filler system, combined with POE toughening modification, to achieve for the first time a synergistic improvement in the triple performance of EPDM materials: corrosion resistance, high toughness, and stable pore structure, resolving the contradiction that traditional materials cannot simultaneously achieve both corrosion resistance and noise reduction. By employing a two-component composite gradient foaming system and precisely controlling the macroporous-microporous composite pore structure, the technical bottleneck of poor low-frequency noise reduction in traditional single-foaming materials is overcome, achieving efficient noise reduction across the entire frequency band.

[0056] In conclusion, the above description is only a preferred embodiment of the present invention and is 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. A corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material, characterized in that: The raw materials include the following parts by weight: 60-75 parts of ethylene propylene rubber raw rubber, 15-22 parts of modified corrosion-resistant filler, 4-8 parts of composite foaming agent, 2-4 parts of crosslinking agent, 1.5-3 parts of activator, 1-2.5 parts of aging-resistant additive, 0.8-1.8 parts of dispersing lubricant, and 3-6 parts of toughening modifier.

2. The corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to claim 1, characterized in that: The raw materials include the following parts by weight: 65-70 parts of ethylene propylene rubber raw rubber, 17-20 parts of modified corrosion-resistant filler, 5-7 parts of composite foaming agent, 2.5-3.5 parts of crosslinking agent, 2-2.5 parts of activator, 1.5-2 parts of aging-resistant additive, 1.2-1.4 parts of dispersing lubricant, and 4-5 parts of toughening modifier.

3. The corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to claim 1, characterized in that: The raw materials include the following parts by weight: 68 parts of ethylene propylene rubber raw rubber, 18 parts of modified corrosion-resistant filler, 6 parts of composite foaming agent, 3 parts of crosslinking agent, 2.3 parts of activator, 1.8 parts of anti-aging additive, 1.3 parts of dispersing lubricant, and 4.5 parts of toughening modifier.

4. The corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to claim 1, characterized in that: The ethylene propylene rubber raw material is selected from EPDM rubber, with an ethylene content of 45%-55% and a Mooney viscosity of 60-80. The crosslinking agent is selected from dicumyl peroxide. The aging resistant additive is a compound of antioxidant 1010 and ultraviolet absorber UV-531. The toughening modifier is selected from polyolefin elastomer.

5. The corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to claim 1, characterized in that: The modified corrosion-resistant filler is a compound of talc powder modified with silane coupling agent and nano silica, and the mass ratio of talc powder to nano silica is 3:

1.

6. The corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to claim 1, characterized in that: The composite foaming agent adopts a composite foaming system of azodicarbonamide and sodium bicarbonate, and the mass ratio of azodicarbonamide to sodium bicarbonate is 2:

1.

7. A method for preparing a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to any one of claims 1-6, characterized in that: Includes the following steps: Step 1: Raw material pretreatment. Place the modified corrosion-resistant filler in an oven at 80-90℃ and dry for 2-3 hours to remove moisture and impurities; crush the ethylene propylene rubber raw rubber into rubber blocks for later use. Step 2: Internal mixing. The pretreated ethylene propylene rubber blocks are fed into an internal mixer and heated to 90-100℃ for 5-8 minutes to fully melt the rubber compound. Then, toughening modifier, dispersing lubricant, and modified corrosion-resistant filler are added sequentially, and the mixture is mixed for 4-6 minutes. Finally, crosslinking agent, composite foaming agent, and aging-resistant additives are added, and the mixture is low-temperature mixed for 3-5 minutes to ensure uniform dispersion of all components without agglomeration or clumping. The resulting compound is then discharged. Step 3: Thin sheeting. Feed the mixed rubber into the open mill, control the roller gap at 2-4mm, and thin sheet 3-5 times at room temperature to produce a uniform rubber sheet with a thickness of 3-5mm, thus eliminating the internal stress of the rubber compound. Step 4: Segmented preheating treatment. Place the film in the oven for segmented preheating treatment. Step 5: Gradient foaming and crosslinking. Place the preheated film in the mold of the flat vulcanizing machine and use a gradient heating foaming and crosslinking process for crosslinking and curing. Step Six: Cooling, Shaping, and Cutting. After vulcanization, maintain pressure and allow to cool naturally to room temperature. Demold to obtain modified rubber substrate. Cut and trim according to usage requirements to obtain corrosion-resistant, high sound-absorbing, and noise-reducing ethylene propylene rubber material.

8. The method for preparing a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to claim 7, characterized in that: In step four, the segmented preheating process involves preheating at 60°C for 15 minutes in the first segment and at 80°C for 10 minutes in the second segment.

9. The method for preparing a corrosion-resistant ethylene propylene rubber sound-absorbing and noise-reducing material according to claim 7, characterized in that: In step five, during the gradient heating foaming and crosslinking process, the initial temperature is 110℃, the pressure is 5MPa, and the holding time is 8min. Then, the temperature is increased to 135℃, the pressure is 8MPa, and the holding time is 12min.