Rubber plate easy to bend and preparation method thereof
By using carbon nanotubes and fumed silica to form a dense three-dimensional mixed filler network in the rubber sheet, and combining it with a compound silane coupling agent of bis-[γ-(triethoxysilane)propyl]tetrasulfide and KH-550, the problems of stress concentration and reduced flexibility of existing silicone rubber sheets under frequent bending are solved, and a rubber sheet that is easy to bend and structurally stable is realized.
Patent Information
- Application Number
- CN202511329893.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-17
- Publication Date
- 2025-12-02
AI Technical Summary
The technical problem with existing silicone rubber sheets in practical applications is that existing products often increase the proportion of reinforcing fillers, which leads to a decrease in the flexibility of the rubber sheet and a relatively insufficient bending performance. Existing products often enhance structural stability by increasing the proportion of reinforcing fillers, but this often leads to a decrease in the flexibility of the rubber sheet, an increase in bending resistance, difficulty in fitting irregular curved surfaces, and stress concentration during repeated bending, resulting in cracks and breakage.
Carbon nanotubes and fumed silica are used as reinforcing fillers, and a dense three-dimensional mixed filler network is formed by a compound silane coupling agent of bis-[γ-(triethoxysilane)propyl]tetrasulfide and KH-550. This improves the network stability, uniformly transmits and disperses stress, and solves the technical problem of traditional reinforcing fillers losing flexibility after hardening.
This technology improves the flexibility of the rubber sheet while maintaining structural strength, avoiding stress concentration, and extending its service life.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of rubber materials technology, and in particular to an easily bendable rubber sheet and its preparation method. Background Technology
[0002] Rubber sheets are sheet-like products with a certain thickness and a large area, made by vulcanizing rubber as the main material (which may contain reinforcing materials such as fabric or thin metal sheets). They are often simply called rubber sheets.
[0003] Existing silicone rubber sheets still have significant technical shortcomings in practical applications: their flexibility is relatively insufficient. To improve mechanical strength, existing products often enhance structural stability by increasing the proportion of reinforcing fillers. However, this often leads to a decrease in the flexibility of the rubber sheet and an increase in bending resistance. In scenarios requiring frequent bending, overly rigid silicone rubber sheets not only have difficulty conforming to irregular curved surfaces, but are also prone to stress concentration due to repeated bending, resulting in cracks and fractures. Therefore, they cannot meet the requirements for continuous bending. Thus, a flexible rubber sheet and its preparation method are proposed to solve this problem. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides the following technical solution:
[0005] A flexible rubber sheet comprising the following components in parts by weight:
[0006] 90-100 parts of methyl vinyl silicone rubber;
[0007] Plasticizer 8-20 parts;
[0008] 35-45 parts of reinforcing filler;
[0009] Vulcanizing agent 0.8-1.2 parts;
[0010] 3-5 parts of structure control agent;
[0011] The reinforcing filler includes carbon nanotubes and fumed silica, with the carbon nanotubes accounting for 3.5% to 10% of the reinforcing filler.
[0012] As an improvement to the above technical solution, a silane coupling agent is also included, wherein the reinforcing filler comprises 6% to 10% of the silane coupling agent.
[0013] As an improvement to the above technical solution, the silane coupling agent is a compound of bis-[γ-(triethoxysilane)propyl]tetrasulfide and KH-550, and the weight ratio of bis-[γ-(triethoxysilane)propyl]tetrasulfide to KH-550 is (4-10):1.
[0014] As an improvement to the above technical solution, the plasticizer is dimethyl silicone oil.
[0015] As an improvement to the above technical solution, the structuring control agent is hydroxyl silicone oil.
[0016] A method for preparing an easily bendable rubber sheet, comprising the following steps:
[0017] S1: Add the specified amount of methyl vinyl silicone rubber raw rubber into a mixer and masticate for 1-2 minutes; then add the specified amount of structure control agent and silane coupling agent in sequence, and mix at high speed at 140℃~160℃ for 3-5 minutes.
[0018] S2: Discharge the compound from step S1, cool it to room temperature and let it stand for at least 8 hours, then put it back into the internal mixer or open mill for a short re-mixing, add plasticizer and mix evenly.
[0019] S3: Pass the rubber compound obtained in S2 through a two-roll mill. After the rubber temperature drops below 100℃, add the vulcanizing agent and repeatedly pass it through a two-roll mill to ensure that the vulcanizing agent is evenly dispersed.
[0020] S4: Fill the rubber material from S3 into the mold, place it in a hot press molding machine, and perform compression vulcanization at 170℃~180℃ and 10~15MPa for 5~15 minutes.
[0021] S5: Place the product obtained in S4 into a circulating air oven and treat it at 200℃ for 2 to 4 hours.
[0022] The beneficial effects of this invention are:
[0023] Carbon nanotubes can interpenetrate and overlap fumed silica aggregates to form a dense three-dimensional mixed filler network with a "1+1>2" effect. This network not only relies on the strong bonding force between the nano-sized particles of fumed silica and the rubber molecular chains to build the basic reinforcing structure, but also connects the silica aggregates through carbon nanotubes to improve network stability and efficiently transfer and disperse stress.
[0024] The density and flexibility of the hybrid packing network are well-matched. Compared with the single packing network, its stress transmission is more uniform, which can reduce local stress concentration during bending. It ensures both flexibility and structural strength, solving the technical problem of traditional reinforcing packings losing flexibility as they harden. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0026] Unless otherwise specified, the main components involved in the following embodiments of this application are all purchased from commercially available products.
[0027] Example of using dimethyl silicone oil as a plasticizer;
[0028] The structural control agent uses hydroxyl silicone oil as an example.
[0029] Example 1
[0030] 90 kg of methyl vinyl silicone rubber raw rubber was put into an internal mixer and plasticized for 1 minute; then 5 kg of structure control agent, 45 kg of reinforcing filler and 2.7 kg of silane coupling agent were added in sequence, and the mixture was sheared and mixed at high speed at 140°C for 3 minutes.
[0031] Discharge the above-mentioned compound, cool it to room temperature and let it stand for at least 8 hours, then put it back into the internal mixer or open mill for a short re-mixing, add 8 kg of plasticizer and mix evenly.
[0032] The well-mixed rubber compound is passed through a two-roll mill in a thin pass. After the rubber temperature drops below 100℃, 0.8kg of vulcanizing agent is added, and the mixture is passed through the mill in a thin pass repeatedly to form triangular clumps.
[0033] The rubber compound, which is repeatedly thinned and punched into triangular shapes, is filled into the mold and placed in a hot press molding machine. It is then subjected to compression molding and vulcanization at 170℃ and 10MPa for 5 minutes.
[0034] The vulcanized product is placed in a circulating air drying oven and treated at 200°C for 2 hours to obtain a rubber sheet.
[0035] The reinforcing filler includes carbon nanotubes and fumed silica, with the carbon nanotubes accounting for 3.5% of the reinforcing filler.
[0036] Example 2
[0037] 95 kg of methyl vinyl silicone rubber raw rubber was put into an internal mixer and plasticized for 2 minutes; then 4 kg of structure control agent, 40 kg of reinforcing filler and 2.4 kg of silane coupling agent were added in sequence, and the mixture was sheared and mixed at high speed at 150°C for 4 minutes.
[0038] Discharge the above-mentioned compound, cool it to room temperature and let it stand for at least 8 hours, then put it back into the internal mixer or open mill for a short re-mixing, add 15 kg of plasticizer and mix evenly.
[0039] The well-mixed rubber compound is passed through a two-roll mill in a thin pass. After the rubber temperature drops below 100℃, 0.8kg of vulcanizing agent is added, and the mixture is passed through the mill in a thin pass repeatedly to form triangular clumps.
[0040] The rubber compound, which is repeatedly thinned and punched into a triangular shape, is filled into the mold and placed in a hot press molding machine. It is then subjected to compression molding and vulcanization at 175℃ and 13MPa for 10 minutes.
[0041] The vulcanized product is placed in a circulating air drying oven and treated at 200°C for 2 hours to obtain a rubber sheet.
[0042] The reinforcing filler includes carbon nanotubes and fumed silica, with the carbon nanotubes accounting for 3.5% of the reinforcing filler.
[0043] Example 3
[0044] 100 kg of methyl vinyl silicone rubber raw rubber was put into an internal mixer and plasticized for 2 minutes; then 3 kg of structure control agent, 35 kg of reinforcing filler and 2.1 kg of silane coupling agent were added in sequence, and the mixture was sheared and mixed at high speed at 160°C for 5 minutes.
[0045] Discharge the above-mentioned compound, cool it to room temperature and let it stand for at least 8 hours, then put it back into the internal mixer or open mill for a short re-mixing, add 20 kg of plasticizer and mix evenly.
[0046] The well-mixed rubber compound is passed through a two-roll mill in a thin pass. After the rubber temperature drops below 100℃, 0.8kg of vulcanizing agent is added, and the mixture is passed through the mill in a thin pass repeatedly to form triangular clumps.
[0047] The rubber compound, which is repeatedly thinned and punched into triangular shapes, is filled into the mold and placed in a hot press molding machine. It is then subjected to compression molding and vulcanization at 170℃ and 15MPa for 15 minutes.
[0048] The vulcanized product is placed in a circulating air drying oven and treated at 200°C for 4 hours to obtain a rubber sheet.
[0049] The reinforcing filler includes carbon nanotubes and fumed silica, with the carbon nanotubes accounting for 3.5% of the reinforcing filler.
[0050] Performance testing:
[0051] The tensile strength at break was tested according to the method in GB / T528-2009.
[0052] Flexural modulus and flexural strength were tested according to GB / T 9341-2008.
[0053] The rubber sheets of Examples 1-3 were subjected to the above performance tests, and the test results are shown in Table 1.
[0054]
[0055]
[0056] Table 1
[0057] As shown in Table 1, the flexural modulus is >300MPa, the flexural strength is >8MPa, and the tensile strength at break is >45MPa, indicating that the rubber sheet prepared by this invention has excellent mechanical properties.
[0058] Fumed silica, with its nanoscale particle size and huge specific surface area, can form an extremely strong physical and chemical bond with rubber molecular chains and form a three-dimensional network structure in the rubber matrix. Carbon nanotubes work synergistically with fumed silica to further strengthen the filler network. The addition of carbon nanotubes can connect fumed silica aggregates to form a more stable mixed filler network, thereby effectively transferring and dispersing stress and significantly improving the modulus and strength of the material.
[0059] Example 4
[0060] The difference from Example 1 is that the carbon nanotubes account for 4% of the reinforcing filler.
[0061] Example 5
[0062] The difference from Example 1 is that the carbon nanotubes account for 5% of the reinforcing filler.
[0063] Example 6
[0064] The difference from Example 1 is that the carbon nanotubes account for 6% of the reinforcing filler.
[0065] Example 7
[0066] The difference from Example 1 is that the carbon nanotubes account for 7% of the reinforcing filler.
[0067] Example 8
[0068] The difference from Example 1 is that the carbon nanotubes account for 8% of the reinforcing filler.
[0069] Example 9
[0070] The difference from Example 1 is that the carbon nanotubes account for 9% of the reinforcing filler.
[0071] Example 10
[0072] The difference from Example 1 is that the carbon nanotubes account for 10% of the reinforcing filler;
[0073] Comparative Example 1
[0074] The difference from Example 1 is that the reinforcing filler is only fumed silica.
[0075] The rubber sheets of Examples 4 to 10 and Comparative Example 1 were subjected to performance tests, and the test results are shown in Table 2.
[0076]
[0077] Table 2
[0078] As shown in Table 2, the addition of carbon nanotubes can greatly improve the flexural modulus, flexural strength and tensile strength at break of silicone rubber. In this experimental system, the comprehensive mechanical properties reach the best value when the proportion of carbon nanotubes is 5%.
[0079] When CNTs are added, they produce a synergistic effect with fumed silica, where 1+1>2. CNTs can penetrate, overlap, and connect silica aggregates to form a denser and stronger three-dimensional network structure. This three-dimensional network structure can effectively transfer and disperse external stress. CNTs have extremely high specific surface energy and tend to attract each other and entangle into clusters to reduce the system's energy. When the CNT content exceeds 5%, the mechanical properties decrease.
[0080] Example 11
[0081] The difference from Example 1 is that the silane coupling agent comprises 7% of the reinforcing filler;
[0082] Example 12
[0083] The difference from Example 1 is that the silane coupling agent comprises 8% of the reinforcing filler;
[0084] Example 13
[0085] The difference from Example 1 is that the silane coupling agent comprises 9% of the reinforcing filler;
[0086] Example 14
[0087] The difference from Example 1 is that the silane coupling agent comprises 10% of the reinforcing filler;
[0088] The rubber sheets of Examples 11-14 and Comparative Example 1 were subjected to performance tests, and the test results are shown in Table 3.
[0089]
[0090] Table 3
[0091] As shown in Table 3, the role of silane coupling agent is to build a molecular bridge between reinforcing filler and organic rubber. The alkoxy group at one end reacts with the hydroxyl group on the surface of the filler, and the organic functional group at the other end participates in the vulcanization network of the rubber. However, when the content of silane coupling agent exceeds 8% of the reinforcing filler, the mechanical properties decrease.
[0092] Example 15
[0093] The difference from Example 11 is that the weight ratio of bis-[γ-(triethoxysilyl)propyl]tetrasulfide to KH-550 is 4:1.
[0094] Example 16
[0095] The difference from Example 11 is that the weight ratio of bis-[γ-(triethoxysilyl)propyl]tetrasulfide to KH-550 is 5:1.
[0096] Example 17
[0097] The difference from Example 11 is that the weight ratio of bis-[γ-(triethoxysilyl)propyl]tetrasulfide to KH-550 is 6:1.
[0098] Example 18
[0099] The difference from Example 11 is that the weight ratio of bis-[γ-(triethoxysilyl)propyl]tetrasulfide to KH-550 is 7:1.
[0100] Example 19
[0101] The difference from Example 11 is that the weight ratio of bis-[γ-(triethoxysilyl)propyl]tetrasulfide to KH-550 is 8:1.
[0102] Example 20
[0103] The difference from Example 11 is that the weight ratio of bis-[γ-(triethoxysilyl)propyl]tetrasulfide to KH-550 is 9:1.
[0104] Example 21
[0105] The difference from Example 11 is that the weight ratio of bis-[γ-(triethoxysilyl)propyl]tetrasulfide to KH-550 is 10:1.
[0106] Comparative Example 2
[0107] The difference from Example 11 is that the silane coupling agent contains only bis-[γ-(triethoxysilane)propyl]tetrasulfide.
[0108] Comparative Example 3
[0109] The difference from Example 11 is that the silane coupling agent contains only KH-550.
[0110] The rubber sheets of Examples 15-21 and Comparative Examples 2-3 were subjected to performance tests, and the test results are shown in Table 4.
[0111]
[0112] Table 4
[0113] As shown in Table 4, the combination of bis-[γ-(triethoxysilyl)propyl]tetrasulfide (Si-69) and KH-550 can greatly improve the flexural modulus, flexural strength and tensile strength at break of silicone rubber, resulting in the comprehensive mechanical properties of the rubber sheet showing an upward trend followed by a downward trend, and the effect is far better than using a single coupling agent.
[0114] The main task of KH-550 is to fully coat the filler particles, reduce their surface energy, and prevent the fillers from getting close to each other through the steric hindrance effect, thereby achieving the ultimate and uniform dispersion during the mixing stage, laying a solid foundation for building a perfect reinforcing network.
[0115] The primary function of Si-69 is to build a robust bridge between well-dispersed fillers and rubber molecules, efficiently transferring the load from the flexible rubber matrix to the rigid filler network through its strong covalent bonds.
[0116] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A flexible rubber sheet, characterized in that, Includes the following components by weight: 90-100 parts of methyl vinyl silicone rubber; Plasticizer 8-20 parts; 35-45 parts of reinforcing filler; Vulcanizing agent 0.8-1.2 parts; 3-5 parts of structure control agent; The reinforcing filler includes carbon nanotubes and fumed silica, with the carbon nanotubes accounting for 3.5% to 10% of the reinforcing filler.
2. The easily bendable rubber sheet according to claim 1, characterized in that: It also includes a silane coupling agent, wherein the reinforcing filler comprises 6% to 10% of the silane coupling agent.
3. The easily bendable rubber sheet according to claim 2, characterized in that: The silane coupling agent is a compound of bis-[γ-(triethoxysilane)propyl]tetrasulfide and KH-550, with a weight ratio of (4-10):1 between bis-[γ-(triethoxysilane)propyl]tetrasulfide and KH-550.
4. The easily bendable rubber sheet according to claim 3, characterized in that: The plasticizer is dimethyl silicone oil.
5. The easily bendable rubber sheet according to claim 1, characterized in that: The structuring control agent is hydroxyl silicone oil.
6. A method for preparing an easily bendable rubber sheet, comprising manufacturing an easily bendable rubber sheet as described in any one of claims 1-5, characterized in that: S1: Add the specified amount of methyl vinyl silicone rubber raw rubber into a mixer and masticate for 1-2 minutes; then add the specified amount of structure control agent and silane coupling agent in sequence, and mix at high speed at 140℃~160℃ for 3-5 minutes. S2: Discharge the compound from step S1, cool it to room temperature and let it stand for at least 8 hours, then put it back into the internal mixer or open mill for a short re-mixing, add plasticizer and mix evenly. S3: Pass the rubber compound obtained in S2 through a two-roll mill. After the rubber temperature drops below 100℃, add the vulcanizing agent and repeatedly pass it through a two-roll mill to ensure that the vulcanizing agent is evenly dispersed. S4: Fill the mold with the rubber material from S3, place it in a hot press molding machine, and perform compression vulcanization at 170℃~180℃ and 10~15MPa for 5~15 minutes. S5: Place the product obtained in S4 into a circulating air oven and treat it at 200℃ for 2 to 4 hours.