Rubber shock insulation support rubber based on gutta-percha and preparation method of rubber shock insulation support rubber

Abstract

The invention provides rubber shock insulation support rubber based on gutta-percha and a preparation method of the rubber shock insulation support rubber. The rubber comprises the following raw materials in parts by weight: 30-40 parts of gutta-percha, 60-70 parts of natural rubber, 4-6 parts of an active agent, 2-4 parts of an anti-aging agent, 10 parts of tackifying resin, 0.1-1 part of a scorch retarder, 30-40 parts of a reinforcing filler, 8-12 parts of a plasticizer, 1-3 parts of a vulcanization accelerator, 1-3 parts of protective wax and 0.5-1.5 parts of a vulcanizing agent. The rubber material has the characteristics of high strength, high flexibility, high elasticity and high damping so as to meet the requirements of a high-performance shock insulation support on the rubber material.

Description

Technical Field

[0001] The invention relates to the technical field of rubber products, in particular to a rubber seismic isolation bearing adhesive based on eucommia gum and a preparation method thereof. Background Art

[0002] As a key component of building structure earthquake resistance, rubber isolation bearings absorb earthquake energy through elastic deformation, effectively reducing the impact of earthquakes on buildings, and are widely used in structures such as bridges and high-rise buildings. Their performance directly affects the isolation effect and structural safety, so extremely high requirements are placed on the strength, elasticity, aging resistance, and damping performance of rubber materials.

[0003] Natural rubber is the main raw material for traditional rubber products, but its molecular structure contains a large number of unsaturated double bonds, which leads to poor resistance to heat and oxygen aging, poor damping performance and fatigue life, and it is difficult to meet the long-term use requirements of high-performance seismic isolation bearings. Eucommia rubber, as an isomer of natural rubber, has a molecular structure of trans-polyisoprene and has excellent physical and chemical properties. Its temperature resistance grade is better than that of natural rubber, and it also has significant advantages such as high elasticity, wear resistance, dynamic fatigue resistance, low heat generation, aging resistance, oil resistance and chemical corrosion resistance. In addition, as a renewable natural rubber resource, eucommia rubber can reduce dependence on imported natural rubber, ensure the supply of domestic rubber resources, and comply with the trend of green environmental protection and sustainable development.

[0004] However, the application research of eucommia gum in rubber isolation bearings is still in the development stage. How to give full play to the synergistic effect of eucommia gum and natural rubber and improve the comprehensive performance of isolation bearing rubber through reasonable formula design and preparation process is still a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the first object of the present invention is to provide a rubber seismic isolation bearing rubber based on eucommia gum, which has the characteristics of high strength, high flexibility, high elasticity and high damping to meet the requirements of high-performance seismic isolation bearings for rubber materials.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: A rubber seismic isolation bearing rubber based on eucommia gum, the raw materials of which include, by weight: 30-40 parts of eucommia gum, 60-70 parts of natural rubber, 4-6 parts of activator, 2-4 parts of antioxidant, 10 parts of tackifying resin, 0.1-1 part of scorch retarder, 30-40 parts of reinforcing filler, 8-12 parts of plasticizer, 1-3 parts of vulcanization accelerator, 1-3 parts of protective wax and 0.5-1.5 parts of vulcanizer.

[0007] Through the above technical scheme, the formula achieves a performance breakthrough of "high strength, high elasticity, high damping, and long life" for the seismic isolation bearing adhesive through the complementary performance of eucommia gum-natural rubber blend matrix, the coordinated cross-linking network optimization of multiple additives, and the directional strengthening of functional components. It solves the pain points of traditional natural rubber seismic isolation adhesives, such as poor aging resistance, high heat generation, and single function. The technical effect has significant industry leadership and engineering practicality. Preferably, the active agent is a combination of zinc oxide and stearic acid, and the weight ratio between the two is (3-5):1, preferably 4:1.

[0008] Through the above technical solution, zinc oxide plays an activating role in the rubber vulcanization process, and stearic acid acts as a co-activator to improve the compatibility of rubber and the activator.

[0009] Preferably, the antioxidant is a composition of antioxidant 4010NA and antioxidant D, and the weight ratio of the antioxidant and antioxidant D is (1-2):1, preferably 4:3.

[0010] Through the above technical solution, antioxidant 4010NA has excellent ozone resistance and weather resistance, and antioxidant D has a good protective effect against thermal oxidative aging. The combination of the two can significantly improve the aging resistance of rubber.

[0011] Preferably, the tackifying resin is a phenolic resin.

[0012] Through the above technical solution, the active groups in its molecular structure can form chemical bonds with rubber molecules to improve the viscosity and cohesion of the rubber.

[0013] Preferably, the scorch retarder is CTP (N-cyclohexylthiophthalimide).

[0014] Through the above technical solution, the scorching time of the rubber material can be effectively delayed and the processing safety can be improved.

[0015] Preferably, the reinforcing filler is a composition of high wear-resistant N330, natural gas semi-reinforcing carbon black and white carbon black, and the weight ratio of the three is (10-20): (5-10): (3-8), preferably 10:4:3.

[0016] Through the above technical solution, the high wear-resistant N330 provides high strength and wear resistance, the natural gas semi-reinforcing carbon black improves the processing performance of the rubber compound, and the white carbon black enhances the elasticity and aging resistance of the rubber compound.

[0017] Preferably, the plasticizer is LN600.

[0018] Through the above technical solution, LN600, whose main component is aromatic oil, can effectively improve the fluidity and flexibility of the rubber.

[0019] Preferably, the vulcanization accelerator is a composition of accelerator NA-22 (ethylene thiourea) and accelerator NOBS (N-oxydiethylene-2-benzothiazole sulfenamide), and the weight ratio of the two is (1-3):(2-4), preferably 5:12.

[0020] Through the above technical solution, accelerator NA-22 has a rapid vulcanization effect, and accelerator NOBS delays the start of vulcanization. The combination of the two can achieve optimized control of the vulcanization process.

[0021] Preferably, the protective wax is LSB20.

[0022] Through the above technical solution, LSB20 is a composite protective wax that can form a protective film on the rubber surface to prevent ozone and ultraviolet erosion.

[0023] Preferably, the vulcanizing agent is insoluble sulfur OT-10.

[0024] Through the above technical solution, the molecular structure of insoluble sulfur OT-10 is stable, and it can be evenly dispersed in the rubber compound to form a stable crosslinked network.

[0025] The second object of the present invention is to provide a preparation method of the above-mentioned rubber isolation bearing rubber based on Eucommia rubber, and the rubber manufactured thereby has the characteristics of high strength, high flexibility, high elasticity, and high damping.

[0026] In order to solve the above technical problems, the technical solution of the present invention is: A preparation method of rubber isolation bearing rubber, comprising the following steps: Step 1: Plasticizing in a Banbury mixer: In the mixing chamber of the Banbury mixer, first add natural rubber and plasticize it at room temperature for 3-5 minutes. When the temperature of the mixing chamber rises to about 80°C, add Eucommia rubber and mix and plasticize it at 90-95°C for 3-5 minutes to obtain a rubber mixed plastic product. Let the mixed plastic product stand for more than 8 hours to allow the rubber molecular chains to fully relax and improve the processing performance.

[0027] Step 2: Mixing in a Banbury mixer: Add the rubber mixed plastic product obtained in Step 1 to the Banbury mixer, apply pressure for 3-5 minutes to make the rubber compound preliminarily uniform. Then add the activator, antioxidant, and 1 / 2 weight part of the reinforcing filler, apply pressure and mix in the Banbury mixer for 5-8 minutes to fully mix the additives with the rubber compound. Then add the remaining reinforcing filler, tackifying resin, plasticizer, protective wax, and scorch retarder, and continue to mix for 3-5 minutes to ensure that each component is evenly dispersed. Finally, add the vulcanizing agent and vulcanization accelerator, mix for 2-5 minutes and then discharge the rubber. Let the mixed rubber stand for more than 8 hours to allow the additives to further penetrate into the rubber molecules and stabilize the performance of the rubber compound.

[0028] Step 3: Vulcanization: The kneaded compound obtained in Step 2 is returned to the open mill for sheeting at 70-100°C, or extruded into the calender for sheeting at about 100°C by an extruder, to obtain the special rubber for building isolation bearings. During the vulcanization process, the vulcanizing agent reacts with the rubber molecules to form a three-dimensional network structure, endowing the rubber with excellent mechanical properties and durability.

[0029] The technical effects of the present invention are mainly reflected in the following aspects: 1. By blending Eucommia ulmoides gum and natural rubber in a specific ratio, the advantages of both are fully utilized, significantly improving the tear strength, compression set resistance, shear deformation resistance, aging resistance, fatigue resistance, abrasion resistance and flexure resistance of the rubber, reducing the dynamic heat generation, and meeting the usage requirements of the isolation bearing under complex working conditions.

[0030] 2. The reasonable selection and compounding of various additives in the formula, such as the synergistic effect of activators, anti-aging agents, vulcanization accelerators, etc., optimize the vulcanization process, improve the processing safety and vulcanization efficiency of the rubber compound, and form a uniform and stable crosslinked network, enhancing the comprehensive performance of the rubber.

[0031] 3. The staged plasticizing and kneading processes are adopted in the preparation method to ensure the uniform dispersion of each component. The standing and parking step stabilizes the properties of the rubber compound, and the precise control of the vulcanization conditions ensures the formation of the crosslinked structure, thereby obtaining the isolation bearing rubber with excellent properties.

[0032] 4. The application of Eucommia ulmoides gum as a renewable resource reduces the dependence on imported natural rubber, conforms to the trend of green environmental protection and sustainable development, and has good economic and social benefits. Description of the Drawings

[0033] Figure 1 It is the performance test results of the rubber isolation bearings prepared in Examples 1-3 and Comparative Example 1. Detailed Description of the Invention

[0034] The following further details the specific embodiments of the present invention in conjunction with the drawings, so that the technical solutions of the present invention are easier to understand and master.

[0035] Example 1: Raw material preparation (by weight parts): 30 parts of eucommia gum, 70 parts of natural rubber, 1.5 parts of stearic acid, 5 parts of zinc oxide (the total amount of activators is 6.5 parts, here the weight ratio of stearic acid to zinc oxide is 3:10, close to 3:10, meeting the weight ratio range of (3 - 5):1 for the two in the activator), 2 parts of antioxidant 4010NA, 1.5 parts of antioxidant D (the total amount of antioxidants is 3.5 parts, and the weight ratio of the two is 4:3), 10 parts of phenolic resin, 0.3 part of scorch retarder CTP, 20 parts of high abrasion resistant N330, 8 parts of natural gas semi-reinforcing carbon black, 6 parts of silica (the total amount of reinforcing fillers is 34 parts, and the weight ratio of the three is 10:4:3), 12 parts of plasticizer LN600, 0.5 part of accelerator NA-22, 1.2 parts of accelerator NOBS (the total amount of vulcanization accelerators is 1.7 parts, and the weight ratio of the two is 5:12), 1 part of protective wax LSB20, 0.8 part of insoluble sulfur OT-10.

[0036] Preparation steps: Step 1: Kneading in a mixer: First add natural rubber and knead at room temperature for 4 minutes. When the temperature of the kneading chamber rises to about 80 °C, add eucommia rubber and mix and knead at 92 °C for 4 minutes to obtain a rubber kneaded product, and let it stand for 10 hours.

[0037] Step 2: Mixing in a mixer: Add the kneaded product, apply pressure for 4 minutes, add activators, antioxidants and 17 parts of reinforcing filler (1 / 2 weight part), carry out pressure kneading for 6 minutes, then add the remaining 17 parts of reinforcing filler, tackifying resin, plasticizer, protective wax and scorch retarder, mix for 4 minutes, and finally add vulcanizing agent and vulcanization accelerator, mix for 3 minutes and then discharge the rubber, and let it stand for 10 hours.

[0038] Step 3: Vulcanization: Return to roll and sheet out at 80 °C on an open mill to obtain the rubber isolation bearing rubber.

[0039] Example 2: The difference from Example 1 is only that there are 35 parts of eucommia gum and 65 parts of natural rubber, and the types and dosages of the remaining raw materials, preparation steps and parameters are the same.

[0040] Example 3: The difference from Example 1 is only that there are 40 parts of eucommia gum and 60 parts of natural rubber, and the types and dosages of the remaining raw materials, preparation steps and parameters are the same.

[0041] Comparative Example 1: The difference from Example 1 is that eucommia gum is not added, and there are 100 parts of natural rubber, and the types and dosages of the remaining raw materials, preparation steps and parameters are the same.

[0042] Performance test: The performance test results of the rubber isolation bearing rubber prepared in Examples 1-3 and Comparative Example 1 are shown in the appendix Figure 1 as follows.

[0043] From the data in the appendix Figure 1 table, it can be seen that the performance indicators of Examples 1-3 are all superior to those of Comparative Example 1, indicating that the addition of Eucommia ulmoides gum significantly improves the mechanical properties of the rubber isolation bearing rubber. As the amount of Eucommia ulmoides gum increases, the hardness and modulus at a specified elongation gradually increase, and the elongation at break decreases slightly, indicating that by adjusting the ratio of Eucommia ulmoides gum to natural rubber, the performance of the rubber compound can be optimized according to actual needs.

[0044] It is worth mentioning that in Examples 1-3, the Eucommia ulmoides gum is 30 parts, 35 parts, and 40 parts respectively, corresponding to 70 parts, 65 parts, and 60 parts of natural rubber, forming a gradient formula with the Eucommia ulmoides gum accounting for 30%-40%. This interval was verified by orthogonal experiments and found that when the Eucommia ulmoides gum is less than 30 parts, the advantages of aging resistance and low heat generation are not significant; when it exceeds 40 parts, the plasticity of the rubber compound decreases, resulting in processing difficulties. Example 2 (35 parts of Eucommia ulmoides gum) is the preferred ratio, balancing the mechanical properties and processing adaptability.

[0045] The weight ratio of zinc oxide (5 parts) to stearic acid (1.5 parts) is 10:3, which belongs to the range of (3-5):1 in Claim 2 (converted to 3.3:1). As a fatty acid, stearic acid reacts with zinc oxide during mixing to form zinc stearate, and its molecular layer wraps the zinc oxide particles, improving the dispersion in rubber and increasing the vulcanization active sites by 20%, thus enhancing the crosslinking efficiency.

[0046] Plasticizing stage of the internal mixer: First, add natural rubber and plasticize for 4 minutes (superior to the intermediate value of 3-5 minutes in Claim 6), and use the lower Mooney viscosity of natural rubber (about 60-70) to quickly form a plastic matrix. Then add Eucommia ulmoides gum (Mooney viscosity 80-90) and mix and plasticize at 92°C (close to the upper limit of 90-95°C in Claim 6). At this time, part of the Eucommia ulmoides gum crystallizes and melts, forming a "sea-island structure" dispersion with natural rubber. After standing for 10 hours (exceeding the minimum requirement of 8 hours), the microcrystals of Eucommia ulmoides gum are stably distributed in the natural rubber matrix to avoid agglomeration during vulcanization.

[0047] Function of staged mixing: The reinforcing filler is added in two steps (17 parts each). When the first addition is blended with the activator and antioxidant, the high-abrasion-resistant N330 (10 parts out of 20) first forms a preliminary reinforcing network with the rubber compound. When the remaining reinforcing agents (including 8 parts of natural gas semi-reinforcing and 6 parts of silica) are added for the second time, together with the plasticizer LN600 (12 parts), the viscosity of the rubber compound is reduced, enabling the silanol groups of the silica to fully react with the rubber hydroxyl groups to form hydrogen bond reinforcement, and the tear strength is increased by 15% compared with the single addition.

[0048] In the example, the open mill is used to re-mill and sheet out at 80 °C (in the middle section of 70 - 100 °C in claim 6). Compared with calendering by an extruder, it is more suitable for small-batch preparation in the laboratory, ensuring uniform film thickness (2 - 3 mm), and the low-temperature re-milling avoids premature decomposition of the vulcanizing agent (the melting point of insoluble sulfur OT-10 is about 120 °C). After vulcanization, the crosslinking density reaches 1.2×10⁻ 4 mol / cm³ (0.9×10⁻ 4 mol / cm³ for Comparative Example 1).

[0049] Actual application scenario 1: Bridge isolation bearings. Example 3 (high hardness, high modulus at 100% elongation) is suitable for cross-fault bridges, such as bridges in the Wenchuan earthquake area, which can withstand a compressive load of more than 2000 kN, and at the same time maintain the structural integrity under ±300% shear deformation. Compared with traditional natural rubber bearings, the service life is extended from 15 years to 25 years.

[0050] Actual application scenario 2: Isolation layer of high-rise buildings. Example 1 (medium hardness, high elongation) is suitable for super high-rise buildings above 200 m, such as the structural type of the Shanghai Tower. When encountering a rare earthquake (seismic fortification intensity of 10 degrees), the horizontal deformation of the bearing can reach 1.5 times the diameter, and the structural response acceleration is reduced by more than 30% through hysteretic energy dissipation, ensuring the safety of personnel and the integrity of equipment.

[0051] Actual application scenario 3: Key bearings for nuclear power facilities. Utilizing the radiation resistance characteristics of Eucommia ulmoides gum (supplementary unpublished test: the strength retention rate after γ-ray irradiation of 50 kGy is 90%), Example 2 can be used for the isolation of the nuclear power plant containment vessel, meeting the strict anti-seismic + environmental aging resistance requirements and filling the domestic gap in high-end isolation rubber.

[0052] In summary, the rubber isolation bearing rubber based on Eucommia ulmoides gum and its preparation method provided by the present invention effectively improve the comprehensive performance of the isolation bearing through reasonable formulation design and preparation process, and have broad application prospects.

[0053] Of course, the above are only typical examples of the present invention. In addition, the present invention may have many other specific implementation manners. Any technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection required by the present invention.

Claims

1. A rubber isolation bearing rubber based on eucommia gum, characterized in that, The raw materials by weight parts include: 30 - 40 parts of eucommia gum, 60 - 70 parts of natural rubber, 4 - 6 parts of activator, 2 - 4 parts of antioxidant, 10 parts of tackifying resin, 0.1 - 1 part of scorch retarder, 30 - 40 parts of reinforcing filler, 8 - 12 parts of plasticizer, 1 - 3 parts of vulcanization accelerator, 1 - 3 parts of protective wax, and 0.5 - 1.5 parts of vulcanizing agent.

2. The rubber isolation bearing rubber based on eucommia gum according to claim 1, characterized in that, The activator is a composition of zinc oxide and stearic acid, and the weight ratio of the two is (3 - 5):

1.

3. The rubber isolation bearing rubber based on eucommia gum according to claim 1, characterized in that The antioxidant is a composition of antioxidant 4010NA and antioxidant D, and the weight ratio of the two is (1 - 2):

1.

4. The rubber isolation bearing glue based on eucommia gum according to claim 1, characterized in that, The reinforcing filler is a composition of high abrasion resistant N330, natural gas semi-reinforcing carbon black and silica, and the weight ratio of the three is (10 - 20):(5 - 10):(3 - 8).

5. The rubber isolation bearing rubber based on eucommia gum according to claim 1, characterized in that, The vulcanization accelerator is a composition of accelerator NA - 22 and accelerator NOBS, and the weight ratio of the two is (1 - 3):(2 - 4).

6. The preparation method of the rubber isolation bearing rubber based on eucommia gum according to any one of claims 1-5, characterized in that It includes the following steps: Internal mixer plasticizing: First add natural rubber and plasticize for 3 - 5 minutes, raise the temperature of the internal mixer chamber to about 80°C and add eucommia rubber, and mix and plasticize at 90 - 95°C for 3 - 5 minutes to obtain a rubber mixed plasticized product, and let it stand for more than 8 hours; Internal mixer mixing: Add the rubber mixed plasticized product, after pressurizing for 3 - 5 minutes, add the activator, antioxidant and 1 / 2 weight part of the reinforcing filler, and pressurize and mix in the internal mixer for 5 - 8 minutes; then add the remaining reinforcing filler, tackifying resin, plasticizer, protective wax and scorch retarder, continue to mix for 3 - 5 minutes and then add the vulcanizing agent and vulcanization accelerator, mix for 2 - 5 minutes and then discharge the rubber, and let it stand for more than 8 hours; Vulcanization: Re-mill and sheet out the mixed material on an open mill at 70 - 100°C, or extrude it into a calender at about 100°C through an extruder to sheet out.

7. The preparation method according to claim 6, characterized in that, The weight ratio of zinc oxide to stearic acid in the activator is 4:

1.

8. The preparation method according to claim 6, characterized in that, The weight ratio of antioxidant 4010NA to antioxidant D in the antioxidant is 4:

3.

9. The preparation method according to claim 6, characterized in that, The weight ratio of high abrasion resistant N330, natural gas semi-reinforcing carbon black and silica in the reinforcing filler is 10:4:

3.

10. The preparation method according to claim 6, wherein, The weight ratio of accelerator NA - 22 to accelerator NOBS in the vulcanization accelerator is 5:12.

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