Sealing rubber strip and preparation method thereof
By adding high styrene and polycarbonate to ethylene propylene rubber and using polyurethane resin to enhance the interaction, the problem of insufficient hardness of sealant strips is solved, and sealant strips with high hardness and wear resistance are achieved to adapt to diverse window designs.
Patent Information
- Application Number
- CN202510720142.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-07-25
AI Technical Summary
The existing sealant strips are not hard enough, which is difficult to meet the sealing requirements of high-end customized windows, and are prone to deformation or wear during use.
By adding high styrene and polycarbonate to ethylene propylene rubber and enhancing their interactions with polyurethane resin, forming chemical bonds and physical crosslinking, the hardness and wear resistance of the sealant strip are improved.
The prepared sealant strips have high hardness and wear resistance, which can better maintain the stability of shape and size, extend the service life, and adapt to the needs of windows of different shapes.
Smart Images
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Abstract
Description
Technical Field
[0001] This application relates to the technical field of rubber products, and particularly relates to a sealing strip and a preparation method thereof. Background Art
[0002] A sealing strip is a common rubber product, and is often used for sealing in car doors and windows, building doors and windows. The most important uses of the sealing strip are waterproofing, dustproofing, noise reduction and sound insulation. The use of the sealing strip is of great significance for keeping places such as inside the car and indoors clean and comfortable.
[0003] With the pursuit of appearance by people, the design of windows is becoming more and more diverse. Different-shaped windows appear continuously, and naturally, sealing strips with different structures are required. In the prior art, the sealing strip has sufficient flexibility but insufficient hardness. When facing high-end customized windows, the original sealing strip is prone to errors due to insufficient hardness and requires secondary treatment by applying glue. Summary of the Invention
[0004] In order to solve the problem that the existing rubber strip has insufficient hardness and is difficult to meet the sealing requirements of high-end customized windows, this application provides a sealing strip, and the hardness and wear resistance of the sealing strip are improved by adding high styrene to ethylene propylene diene monomer rubber.
[0005] In the first aspect, this application provides a sealing strip, adopting the following technical solution: A sealing strip, comprising the following components in parts by weight: 100 parts of ethylene propylene diene monomer rubber, 5 - 7 parts of polyethylene, 115 - 125 parts of carbon black, 4 - 6 parts of zinc oxide, 1 - 3 parts of stearic acid, 1 - 2 parts of polyethylene wax, 1 - 3 parts of polyethylene glycol, 75 - 85 parts of calcium carbonate, 32 - 37 parts of paraffin oil, 5 - 8 parts of high styrene, 0.6 - 1 part of sulfur, 4.5 - 6 parts of accelerator, and 3 - 5 parts of calcium oxide.
[0006] By adopting the above technical solution, high styrene is a special synthetic rubber, which is mainly made of styrene monomer and obtained through polymerization. High styrene rubber has relatively high hardness and strength, and when incorporated into ethylene propylene diene monomer rubber, it can significantly increase the hardness of the rubber compound. This is mainly because the rigid styrene chain segments of high styrene play a supporting and strengthening role in the rubber, resulting in an increase in the hardness of the entire rubber system. In addition to hardness, high styrene can also increase the stiffness of the rubber, enabling the sealing strip to better maintain the shape and dimensional stability when subjected to external forces. In addition, high styrene rubber has relatively high wear resistance, enabling the sealing strip to better resist wear and maintain its sealing performance during use.
[0007] In this application, by incorporating high styrene into ethylene propylene diene monomer (EPDM) rubber, the styrene segments of high styrene are utilized to increase the hardness and stiffness of the entire system, enabling the prepared sealing strip to have high hardness and wear resistance.
[0008] Preferably, the mass ratio of the ethylene propylene diene monomer (EPDM) rubber to high styrene is 100:6 - 7.
[0009] By adopting the above technical solution, if the content of high styrene is too low, it will not be able to provide sufficient hardness support for the sealing strip. Excessively low hardness may cause the sealing strip to deform or be damaged during use, thereby losing the sealing effect. High styrene has excellent wear resistance. If its content is too low, the wear resistance of the entire sealing strip will be reduced. Insufficient wear resistance will cause the sealing strip to wear rapidly during use, shortening its service life.
[0010] Although high styrene can increase the hardness and wear resistance of the sealing strip, too high a content may lead to a decline in processing performance. During the processing process, problems such as sticking to the roller and die may be more likely to occur, making its distribution uneven in the overall system and reducing wear resistance.
[0011] Preferably, the sealing strip further includes polycarbonate.
[0012] By adopting the above technical solution, polycarbonate is a kind of polymer material with a tightly packed and orderly arranged molecular chain structure. This structural feature enables polycarbonate to have relatively high hardness. When polycarbonate is added to the sealing strip, it can act as a rigid filler to increase the hardness of the entire system. During the preparation process, polycarbonate may undergo a certain degree of cross-linking with other components such as ethylene propylene diene monomer (EPDM) rubber. This cross-linking effect can enhance the intermolecular interaction force, making the entire system more compact and stable, thereby increasing hardness.
[0013] Polycarbonate itself has excellent wear resistance. Its surface is flat and smooth, and it is not easily subject to friction and wear. When polycarbonate is added to the sealing strip, it can effectively resist external friction and wear, extending the service life of the sealing strip. The molecular chain of polycarbonate has relatively high strength and can effectively resist the impact and extrusion of external forces. In the sealing strip, polycarbonate can enhance the molecular chain strength of the entire system, enabling the sealing strip to better maintain the stability of shape and size when subjected to external forces, thereby improving wear resistance.
[0014] Preferably, the weight portion of the polycarbonate is 2 - 5 parts.
[0015] By adopting the above technical solution, when the content of polycarbonate is too low, the improvement of the hardness and wear resistance of the whole system is limited; although polycarbonate can improve the hardness and wear resistance of the sealing strip, too high a content may lead to a decline in processing performance. Polycarbonate has a relatively high melting point. If the content is too high, it will increase the melting temperature of the sealing strip, making the processing process more difficult. The compatibility between polycarbonate and other components (such as high styrene) needs to be controlled within a certain range. If the content is too high, it may lead to poor compatibility between polycarbonate and other components, resulting in problems such as delamination and cracking. Therefore, after a large amount of research and experimental verification by the applicant, it is finally determined that the polycarbonate content in this application is preferably as described above.
[0016] Preferably, the sealing strip further comprises a polyurethane resin.
[0017] By adopting the above technical solution, polyurethane resin is a kind of polymer material prepared by the reaction of isocyanate and polyol. Its molecules contain functional groups such as isocyanate group (-NCO) and hydroxyl group (-OH). The isocyanate group in polyurethane resin has a high reactivity and can react with compounds containing active hydrogen atoms. In high styrene, the hydrogen atoms in the styrene group have a certain activity under certain conditions and can react with the isocyanate group. This reaction can form chemical bonds to connect polyurethane resin and high styrene, thereby enhancing their compatibility.
[0018] The hydroxyl group in polyurethane resin can also react with the carbonate group in polycarbonate. Although the carbonate group itself does not directly contain active hydrogen atoms, under certain conditions, they can generate hydrogen-containing active intermediates through other means (such as hydrolysis, pyrolysis, etc.) and then react with the hydroxyl group. In addition, the interaction between the hydroxyl group and the carbonate group may also enhance the compatibility through physical means such as hydrogen bonding.
[0019] Through the above reactions, polyurethane resin can form chemical bonds or physical crosslinking points between high styrene and polycarbonate, thereby enhancing their interaction and compatibility. This interaction makes the whole system more compact and orderly, which helps to improve the hardness and wear resistance of the system.
[0020] Preferably, the weight part of the polyurethane resin is 1-3 parts.
[0021] By adopting the above technical solution, if the content of the polyurethane resin is too low, it may not be able to fully connect the high styrene and the polycarbonate, resulting in insufficient compatibility and affecting the overall performance of the system. After reaching a certain content, the improvement effect of the polyurethane resin on the performance of the sealing strip will gradually tend to be saturated. If the content is continued to be increased, additional performance improvement may not be obtained, but instead, performance excess and waste of resources will occur. Therefore, after a large amount of research and experimental verification by the applicant, it is finally determined that the content of the polyurethane resin in this application is preferably as above.
[0022] In the second aspect, this application provides a preparation method of a sealing strip, adopting the following technical solution: A preparation method of a sealing strip for preparing the above-mentioned sealing strip, comprising the following steps: Mixing: Mix other components except sulfur, accelerator and calcium oxide according to the formula amount to obtain a mixed rubber. Vulcanization: Extrude the mixed rubber to obtain a semi-finished product; mix the semi-finished product, sulfur, accelerator and calcium oxide and then conduct vulcanization, and then conduct cutting to obtain the sealing strip.
[0023] By adopting the above technical solution, in the mixing stage, mixing other components except sulfur, accelerator and calcium oxide makes various raw materials evenly dispersed in the mixed rubber, which helps to improve the overall performance of the sealing strip. Mixing the semi-finished product, sulfur, accelerator and calcium oxide and then conducting vulcanization can ensure that these additives are evenly distributed during the vulcanization process and fully react with the mixed rubber. This helps to improve key properties such as the hardness, wear resistance and aging resistance of the sealing strip.
[0024] Preferably, before the mixing step, the high styrene and the polyurethane resin are first mixed, and then mixed with the polycarbonate to form a mixture and mix with the remaining components.
[0025] By adopting the above technical solution, the functional groups in the high styrene and the polyurethane resin can interact with each other. For example, the isocyanate groups in the polyurethane resin can react and connect with the active hydrogen atoms in the high styrene to form chemical bonds. This interaction helps to enhance the compatibility between the two, making the mixture more uniform and stable. As a kind of polymer material, the polyurethane resin has good dispersion performance. Mixing it with the high styrene first can more effectively promote the dispersion of the high styrene in the subsequent mixing process with the polycarbonate and avoid the occurrence of agglomeration.
[0026] The pre-mixing of the high styrene and the polyurethane resin can make the two reach the molten state faster during the mixing process, thereby reducing the overall processing temperature. The interaction between the polyurethane resin and the high styrene and their uniform distribution in the mixture help to enhance the hardness of the final product.
[0027] Preferably, in the mixing step, the mixing temperature range is 275 - 295 °C.
[0028] By adopting the above technical solution, when the mixing temperature is too low, the fluidity of raw materials such as high styrene, polyurethane resin, and polycarbonate will be significantly reduced. This will cause the raw materials to be difficult to mix evenly during the mixing process, and phenomena such as agglomeration or uneven dispersion are likely to occur, affecting the performance of the final product. The mixing temperature is an important factor affecting the chemical reaction rate. When the temperature is too low, the chemical reaction rate between raw materials will slow down, and even the reaction may not be complete. This will affect the crosslinking degree and physical properties of the sealing strip.
[0029] When the mixing temperature is too high, raw materials such as high styrene, polyurethane resin, and polycarbonate may undergo decomposition reactions. This will lead to a decline in the performance of the raw materials and even the generation of harmful substances, affecting the quality and safety of the final product.
[0030] In summary, the present application has the following beneficial effects: 1. Since the present application incorporates high styrene into ethylene propylene diene monomer rubber and uses the styrene segments of high styrene to increase the hardness and stiffness of the entire system, the prepared sealing strip has high hardness and wear resistance; 2. The present application also adds polycarbonate, which can act as a rigid filler and undergo a certain degree of crosslinking with other components such as ethylene propylene diene monomer rubber, gradually increasing the hardness of the entire system; in addition, polycarbonate can enhance the molecular chain strength of the entire system, making the hardness and wear resistance of the sealing strip better and better; 3. The present application adds polyurethane resin to continuously enhance the interaction and compatibility between high styrene and polycarbonate, gradually increasing the hardness and wear resistance of the entire system. Specific Embodiments
[0031] The raw materials in the present application include the following parts: Ethylene propylene diene monomer rubber: A commercially available product with a CAS number of 23627 - 24 - 9; Polyethylene: A commercially available product with a CAS number of 9002 - 88 - 4; Carbon black: A commercially available product with a CAS number of 1333 - 86 - 4; Zinc oxide: A commercially available product with a CAS number of 1314 - 13 - 2; Stearic acid: A commercially available product with a CAS number of 57 - 11 - 4; Polyethylene wax: A commercially available product; Polyethylene glycol: A commercially available product with a CAS number of 25322 - 68 - 3; Calcium carbonate: A commercially available product with a CAS number of 471 - 34 - 1; Paraffin oil: A commercially available product with a CAS number of 8012-95-1 is used; High styrene: A commercially available product is used; Sulfur: A commercially available product with a CAS number of 63705-05-5 is used; Accelerator: There are many types of accelerators for vulcanized rubber, including TMTD, DPTT, DTDM, etc. In this application, a commercially available TMTD product with a CAS number of 137-26-8 is used for illustration; Calcium oxide: A commercially available product with a CAS number of 1305-78-8 is used; Polycarbonate: A commercially available product with a CAS number of 24936-68-3 is used; Polyurethane resin: A commercially available product with a CAS number of 9017-09-8 is used; The present application will be further described in detail below in conjunction with examples and comparative examples.
[0032] Example 1 A method for preparing a sealing strip includes the following steps: Mixing: 1000 g of ethylene propylene diene monomer rubber, 60 g of polyethylene, 1200 g of carbon black, 50 g of zinc oxide, 20 g of stearic acid, 15 g of polyethylene wax, 20 g of polyethylene glycol, 800 g of calcium carbonate, 350 g of paraffin oil, and 65 g of high styrene are mixed. The mixing temperature is 285 °C, and the mixing is carried out for 10 min to obtain a mixed rubber; Vulcanization: The mixed rubber is extruded using a rubber screw extruder to obtain a semi-finished product; the semi-finished product, 8 g of sulfur, 55 g of accelerator TMTD, and 40 g of calcium oxide are blended and then vulcanized. The extruded semi-finished product is vulcanized using a five-stage vulcanization furnace at 250 °C, 250 °C, 250 °C, 260 °C, and 260 °C in sequence. The length of each stage of the vulcanization furnace is 8 m, and the conveyor belt speed in each stage of the vulcanization furnace is 18 m / min. After vulcanization is completed, it is cut to obtain a sealing strip.
[0033] Examples 2-5 Based on the preparation method of Example 1, the contents of each component in Examples 2-5 are adjusted. The specific adjustments are shown in Table 1.
[0034] Comparative Examples 1-2 Based on the preparation method of Example 1, high styrene is not added in Comparative Example 1, and the other conditions remain unchanged.
[0035] Based on the preparation method of Example 1, 65 g of high styrene is replaced with 65 g of styrene in Comparative Example 2, and the other conditions remain unchanged.
[0036] Table 1 Component contents (g) and performance test table of Examples 1-5 and Comparative Examples 1-2 Performance detection tests: The sealing rubber strips of Examples 1-5 and Comparative Examples 1-2 were subjected to the following performance detections, and the detection results are shown in Table 1.
[0037] 1. Hardness According to GB / T 531-2008 "Testing Method for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber", the Shore hardness was measured.
[0038] 2. Abrasion resistance According to GB / T 1689-2014 "Determination of Abrasion Resistance of Vulcanized Rubber", the wear amount was measured. The lower the wear amount, the better the abrasion resistance.
[0039] Referring to Table 1, by comparing Examples 1-5 and Comparative Examples 1-2, it can be seen that the hardness of Examples 1-5 is higher than that of Comparative Examples 1-2, and the wear amount is lower than that of Comparative Examples 1-2, indicating that the addition of high styrene is beneficial to improving the hardness and abrasion resistance of the sealing rubber strip.
[0040] As the addition amount of high styrene increases, the hardness of the sealing rubber strip shows a trend of first increasing and then decreasing, and the wear amount shows a trend of first decreasing and then increasing. This may be because as the addition amount of high styrene increases, the rigid styrene chain segments of high styrene play an increasingly large role in supporting and strengthening in the rubber, and due to the excellent abrasion resistance of high styrene itself, the hardness and abrasion resistance of the sealing rubber strip become better; when exceeding a certain range, too high a content may lead to a decline in processing performance, and problems such as sticking to the roll and sticking to the mold may be more likely to occur during the processing, making its distribution uneven in the overall system and reducing the hardness and abrasion resistance of the sealing rubber strip.
[0041] By comparing Examples 1-5, it is found that Example 1 has the best performance. Therefore, Example 1 is selected as the preferred one.
[0042] Examples 6-10 Based on the preparation method of Example 1, 40 g of polycarbonate was kneaded together with ethylene propylene diene monomer rubber, high styrene and other components, and the other conditions remained unchanged in Example 6.
[0043] Based on the preparation method of Example 6, the addition amount of polycarbonate was adjusted in Examples 7-10, and the specific adjustments are shown in Table 2.
[0044] The sealing rubber strips of Examples 6-10 were subjected to the above performance detections, and the test results are shown in Table 2.
[0045] Table 2: Addition amount of polycarbonate and performance detection table of Example 1 and Examples 6-10 Project Example 1 Example 6 Example 7 Example 8 Example 9 Example 10 Polycarbonate / g / 40 15 20 50 60 Hardness 61.4 62.8 61.6 62.1 62.6 62.3 Wear amount / g 0.146 0.121 0.144 0.135 0.127 0.136 Referring to Table 2, by comparing Example 1 with Examples 6 - 10, it can be seen that adding polycarbonate can further improve the hardness and wear resistance of the sealing strip.
[0046] As the addition amount of polycarbonate increases, the hardness of the sealing strip shows a trend of first increasing and then decreasing, and the wear amount shows a trend of first decreasing and then increasing. This may be because as the addition amount of polycarbonate increases, polycarbonate can act as a hard filler and undergo a certain degree of cross-linking with other components such as ethylene propylene diene monomer (EPDM), gradually increasing the hardness of the whole system. In addition, polycarbonate can enhance the molecular chain strength of the whole system, making the hardness and wear resistance of the sealing strip better and better. When exceeding a certain range, too high a content may lead to poor compatibility between polycarbonate and other components, resulting in uneven distribution in the overall system and reducing the hardness and wear resistance of the sealing strip.
[0047] Examples 11 - 16 Based on the preparation method of Example 6, in Example 11, 30 g of polyurethane resin was mixed with components such as ethylene propylene diene monomer (EPDM), high styrene, and polycarbonate, and the other conditions remained unchanged.
[0048] Based on the preparation method of Example 11, in Examples 12 - 15, the addition amount of polyurethane resin was adjusted, and the specific adjustment is shown in Table 3.
[0049] Based on the preparation method of Example 11, in Example 16, 65 g of high styrene and 30 g of polyurethane resin were first mixed, then mixed with 40 g of polycarbonate to form a mixture, and the mixture was mixed with components such as ethylene propylene diene monomer (EPDM), and the other conditions remained unchanged.
[0050] Based on the preparation method of Example 1, in Examples 11 - 16, the addition amount of polyurethane resin was adjusted, and the specific adjustment is shown in Table 3.
[0051] The sealing strips of Examples 11 - 16 were subjected to the above performance tests, and the test results are shown in Table 3 respectively.
[0052] Table 3 Addition amount and performance test table of polyurethane resin in Examples 6 and Examples 11 - 16 Referring to Table 3, by comparing Example 6 with Examples 11 - 16, it can be seen that adding polyurethane resin can further improve the hardness and wear resistance of the sealing strip.
[0053] As the addition amount of polyurethane resin increases, the hardness of the sealing strip shows a trend of increasing first and then leveling off, and the wear amount shows a trend of decreasing first and then leveling off. This may be because as the addition amount of polyurethane resin increases, polyurethane resin continuously enhances the interaction and compatibility between high styrene and polycarbonate, gradually increasing the hardness and wear resistance of the entire system.
[0054] Comparing Example 11 and Example 16, when high styrene is first mixed with polyurethane resin, then together with polycarbonate, and finally mixed with other substances, it can more effectively promote the interaction between polyurethane resin and high styrene and their uniform distribution in the mixture, further increasing the hardness and wear resistance of the entire system.
[0055] Examples 17 - 20 Based on the preparation method of Example 11, Examples 17 - 20 adjust the mixing temperature in the mixing step. The specific adjustments are shown in Table 4.
[0056] Perform the above performance tests on the sealing strips of Examples 17 - 20. The test results are shown in Table 4.
[0057] Table 4 Mixing temperature and performance test table of Example 11 and Examples 17 - 20 Referring to Table 4, comparing Example 11 and Examples 17 - 20, it can be seen that as the mixing temperature increases, the hardness of the sealing strip shows a trend of increasing first and then decreasing, and the wear amount shows a trend of decreasing first and then increasing. This may be because as the mixing temperature increases, the fluidity of raw materials such as high styrene, polyurethane resin, and polycarbonate gradually increases, and the raw materials are fully mixed during the mixing process, making the hardness and wear resistance of the sealing strip better; when exceeding a certain range, raw materials such as high styrene, polyurethane resin, and polycarbonate may undergo decomposition reactions, resulting in a decrease in the performance of the raw materials and reducing the hardness and wear resistance of the sealing strip.
[0058] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.
Claims
1. A sealing strip, characterized in that, Comprising the following components in parts by weight: 100 parts of ethylene propylene diene monomer rubber, 5 - 7 parts of polyethylene, 115 - 125 parts of carbon black, 4 - 6 parts of zinc oxide, 1 - 3 parts of stearic acid, 1 - 2 parts of polyethylene wax, 1 - 3 parts of polyethylene glycol, 75 - 85 parts of calcium carbonate, 32 - 37 parts of paraffin oil, 5 - 8 parts of high styrene, 0.6 - 1 part of sulfur, 4.5 - 6 parts of accelerator, 3 - 5 parts of calcium oxide.
2. The sealing strip according to claim 1, wherein: The mass ratio of the ethylene propylene diene monomer rubber to the high styrene is 100:6 - 7.
3. The sealing strip according to claim 1, wherein: It further comprises polycarbonate.
4. The sealant strip according to claim 3, characterized in that: The parts by weight of the polycarbonate are 2 - 5 parts.
5. The sealing strip according to claim 3, characterized in that: It further comprises polyurethane resin.
6. The sealing strip according to claim 5, characterized in that: The parts by weight of the polyurethane resin are 1 - 3 parts.
7. The preparation method of the sealing strip according to any one of claims 1-6, characterized in that, Comprising the following steps: Mixing: Mix other components except sulfur, accelerator and calcium oxide according to the formula amount to obtain a mixed rubber. Vulcanization: Extrude the mixed rubber to obtain a semi-finished product; mix the semi-finished product, sulfur, accelerator and calcium oxide and then conduct vulcanization, and then conduct cutting to obtain a sealing strip.
8. The preparation method of the sealing strip according to claim 7, characterized in that: Before the mixing step, first mix the high styrene and the polyurethane resin, and then mix with the polycarbonate to form a mixture and mix with the remaining components.
9. The preparation method of the sealing strip according to claim 7, characterized in that: In the mixing step, the temperature range of the mixing is 275 - 295 °C.