High-hardness low dynamic-static ratio rubber material for motor suspension and preparation method thereof

Abstract

The application relates to the technical field of rubber materials, and particularly discloses a high-hardness low-dynamic-static-ratio rubber material for motor suspension and a preparation method thereof. The rubber material comprises the following components in mass fractions: isoprene rubber 30-55 parts, resin-reinforced cis-butadiene rubber 40-60 parts, trans-butadiene rubber 5-20 parts, tear-resistant resin 2-5 parts, carbon black 20-40 parts, reactive plasticizer 3-10 parts, anti-aging agent 1.5-8 parts, modified phenolic resin 6-16 parts, curing agent 0.6-1.5 parts, zinc oxide 4-6 parts, stearic acid 1.5-3 parts, pre-dispersed sulfur 1.0-3.5 parts and accelerator 2-5 parts. Through the synergistic effect of the components, the rubber material with the hardness reaching 60HA and the 100Hz dynamic-static-ratio less than 1.30 and good comprehensive performance is obtained.

Description

Technical Field

[0001] This invention relates to the field of rubber materials technology, and in particular to a high-hardness, low dynamic-to-static ratio rubber material for motor suspension and its preparation method. Background Technology

[0002] Electric vehicles, powered by electricity, represent the mainstream direction of future automotive development. The mechanisms of electric drive differ from those of gasoline and diesel drives, resulting in significant differences in the requirements for motor mounts compared to traditional engine mounts. In traditional gasoline and diesel vehicles, the excitation of the engine primarily stems from the unbalanced inertia generated by crankshaft rotation and the reciprocating force of the crankshaft and connecting rod. Therefore, gasoline and diesel motor mounts are designed with low stiffness to isolate this excitation force. However, pure electric vehicles are different. The excitation of the electric drive assembly mainly originates from electromagnetic forces and high-frequency vibrations caused by gear meshing. Furthermore, during start-up and braking, the motor outputs a very large torque as it passes through the reducer. Therefore, the stiffness of the motor mount must be higher than that of ordinary gasoline and diesel motor mounts: the hardness of the rubber material used in the motor mount must be ≥60HA, far exceeding the requirement for gasoline and diesel engine mounts (50HA). Simultaneously, the main excitation frequency of the powertrain during rapid acceleration in electric vehicles is between 400 and 8000Hz. High stiffness would lead to a decrease in vibration isolation performance; therefore, the motor mount requires low dynamic stiffness under high-frequency conditions.

[0003] Electric vehicle motor mounts must meet the extremely high torque output requirements during start-up and braking, while also providing good vibration isolation performance under rapid acceleration. In terms of mount stiffness, this requires high static stiffness to reduce deformation and displacement under high torque, thereby improving durability, while simultaneously possessing a low dynamic-to-static ratio to meet high-frequency vibration isolation requirements. The static stiffness of the mount is mainly determined by the gel structure and the hardness of the rubber material. Increasing the amount of carbon black in the rubber material can increase its hardness, thus improving mount stiffness; however, this often results in a dynamic-to-static ratio that doesn't meet the requirements. Therefore, finding a rubber material that simultaneously achieves high hardness and a low dynamic-to-static ratio is crucial for the widespread adoption of electric vehicles. Summary of the Invention

[0004] In view of this, the present invention provides a high-hardness, low dynamic-to-static ratio rubber material for motor mounting and its preparation method. The material uses isoprene rubber as the main raw rubber material and is supplemented with resin-reinforced cis-butadiene rubber, trans-butadiene rubber, and other raw rubbers to obtain a rubber material with excellent comprehensive performance, including high hardness, low dynamic-to-static ratio, and excellent fatigue resistance, for use in electric vehicle motor mounting.

[0005] To achieve the above-mentioned objectives, the embodiments of the present invention employ the following technical solutions:

[0006] A high-hardness, low dynamic-to-static ratio rubber material for motor mounting, comprising the following components in parts by weight: isoprene rubber: 30-55 parts, resin-reinforced cis-butadiene rubber: 40-60 parts, trans-butadiene rubber: 5-20 parts, tear-resistant resin: 2-5 parts, carbon black: 20-40 parts, reactive plasticizer: 3-10 parts, antioxidant: 1.5-8 parts, modified phenolic resin: 6-16 parts, curing agent: 0.6-1.5 parts, zinc oxide: 4-6 parts, stearic acid: 1.5-3 parts, pre-dispersed sulfur: 1.0-3.5 parts, and accelerator: 2-5 parts.

[0007] Compared with the prior art, the high-hardness, low dynamic-to-static ratio rubber material for motor mounting provided in this application has the following advantages:

[0008] This application uses isoprene rubber as the main raw rubber material, supplemented with resin-reinforced high cis-1,4 polybutadiene composite material to improve the basic hardness of the rubber material, thereby reducing the amount of carbon black and achieving a high-hardness, low dynamic-static ratio material. The addition of trans-butadiene rubber utilizes its high crystallinity to improve the fatigue resistance and durability of the vulcanized rubber, achieving a low dynamic-static ratio and high durability. The combined use of tear-resistant rubbers improves the dispersion effect of fillers in the rubber, thereby improving the durability of the material. Simultaneously, the modification of the raw rubber system with tear-resistant resin improves the orientation of rubber molecular chains, thereby improving the strain crystallization properties of natural rubber and significantly enhancing the durability of the material. Furthermore, the addition of modified phenolic resin not only reduces the amount of carbon black but also significantly reduces the dynamic-static ratio of the rubber material. The addition of reactive plasticizers improves the processing performance of the rubber during mixing while simultaneously reducing the dynamic-static ratio. Finally, the addition of activating systems such as zinc oxide and stearic acid increases the rate and number of cross-linking bond formation.

[0009] This application overcomes the problem of balancing high suspension stiffness and low dynamic-to-static ratio through the synergistic effect between specific components, and avoids the problem that low dynamic-to-static ratio materials have low tensile strength and tear strength, which cannot meet the product durability requirements. It obtains a rubber material with a hardness of 60HA and a dynamic-to-static ratio of <1.30 at 100Hz, which is suitable for electric vehicle motor suspension.

[0010] Optionally, the resin-reinforced cis-butadiene rubber includes 1,2-meta-isotactic polybutadiene, and the content of the 1,2-meta-isotactic polybutadiene is 0.5wt% to 1.5wt%.

[0011] Further optionally, the content of the 1,2-meta-isotactic polybutadiene is 0.8 wt% to 1 wt%.

[0012] By using 1,2-metaisotrimeric polybutadiene, which has a high melting point and high crystallinity, the reinforcing properties of rubber materials can be significantly improved and its content can be controlled. It can also reduce the amount of carbon black used, solve the problem of large dynamic-to-static ratio of vulcanized rubber caused by the addition of a large amount of carbon black, and avoid the occurrence of rubber lacking elasticity.

[0013] Optionally, the resin-reinforced cis-butadiene rubber has a Mooney viscosity of 30 to 70 under ML1+4 conditions at 100°C.

[0014] Further optionally, the resin-reinforced cis-butadiene rubber has a Mooney viscosity of 40 to 60 under ML1+4 conditions at 100°C.

[0015] By optimizing the Mooney limit, problems such as insufficient rubber material can be avoided, and the rapid flow of rubber material in the mold cavity can also prevent gas from being difficult to expel, which can lead to defects such as bubbles in the product.

[0016] Alternatively, the resin-reinforced cis-butadiene rubber is of type VCR412 and was purchased from Ube Industries, Ltd.

[0017] Optionally, the tear-resistant resin is a mixture of modified rosin and aromatic resin.

[0018] Alternatively, the tear-resistant resin is model RT101A and was purchased from Jiangsu Ruiba New Material Technology Co., Ltd.

[0019] By adding a preferred anti-tear resin with aromatic groups, which has good compatibility with the rubber system and strong interaction, and whose polar groups can improve the dispersion performance of the filler, the filler can enhance the resistance of the filler to the propagation of rubber cracks, and blunt the crack tip to improve the tear resistance of the vulcanized rubber.

[0020] Optionally, the butadiene content in the trans-butadiene rubber is 5wt% to 30wt%.

[0021] Further optionally, the butadiene content in the trans-butadiene rubber is 10wt% to 20wt%.

[0022] By adding trans-butadiene rubber as shown in formula (I), it has good compatibility with other rubbers. Its double bonds can be vulcanized with sulfur, and it has good co-vulcanization characteristics with other rubbers. Furthermore, it has weak crystallinity, which can significantly improve the fatigue resistance of rubber materials to resist the high impact strength of motor high torque output on the suspension.

[0023]

[0024] Optionally, the particle size of the carbon black is 40 nm to 125 nm.

[0025] Further optionally, the particle size of the carbon black is 60 nm to 125 nm.

[0026] By controlling the particle size of carbon black, the physical and mechanical properties of vulcanized rubber, such as tensile strength and tear strength, can be improved.

[0027] Optionally, the modified phenolic resin is a cashew oil-modified phenolic resin.

[0028] In some embodiments, the modified phenolic resin is ZY2000 from Jiangsu Ruiba New Material Technology Co., Ltd.

[0029] By adding a preferred modified phenolic resin, high hardness of the rubber material can be achieved, and the long-chain aliphatic hydrocarbon segments contained therein can be used to effectively improve the brittleness of the resin after curing.

[0030] Optionally, the curing agent is hexamethylenetetramine (HTM) or hexamethoxymethyl melamine (HMMM).

[0031] In some embodiments, the hexamethoxymethyl melamine was purchased from Jiangsu Ruiba New Material Technology Co., Ltd.

[0032] Optionally, the pre-dispersed sulfur uses styrene-butadiene rubber as a carrier, and the sulfur content is 78wt% to 82wt%.

[0033] In some embodiments, the predispersed sulfur is S-80.

[0034] Vulcanization with selected pre-dispersed sulfur can significantly improve the fatigue resistance of rubber materials, meeting the requirements of electric vehicles for high output torque during start-up and emergency braking, and the fatigue durability requirements of rubber materials, especially the fatigue durability requirements for large displacement.

[0035] Optionally, the reactive plasticizer is a polydiolefin or diene copolymer low molecular weight polymer, and the number average molecular weight of the plasticizer is 500 to 10000.

[0036] Optionally, the reactive plasticizer is liquid isoprene rubber or liquid butadiene rubber.

[0037] In some embodiments, the liquid butadiene rubber is IR-563 from Puyang Linshi Chemical New Materials Co., Ltd.

[0038] Adding reactive plasticizers can reduce internal friction between raw rubber and fillers, thereby improving the processing performance of the compound.

[0039] Optionally, the antioxidant is a ketone-amine reaction product and a p-phenylenediamine antioxidant with a mass ratio of 0.5 to 3:1 to 5.

[0040] Optionally, the ketone-amine reaction product is an antioxidant TMQ.

[0041] Optionally, the p-phenylenediamine antioxidant is antioxidant 6PPD.

[0042] By adding selected antioxidants, oxygen free radicals are captured during the thermo-oxidative aging process of vulcanized rubber, reducing the reaction between oxygen free radicals and polymers, thereby improving the material's resistance to thermo-oxidative aging and fatigue durability.

[0043] In some embodiments, the isoprene rubber is IR2200 from Zeon Corporation of Japan.

[0044] Furthermore, the present invention also provides a method for preparing a high-hardness, low-dynamic-to-static-ratio rubber material for motor mounting, comprising the following steps:

[0045] Step 1: Weigh each component according to the raw materials listed above;

[0046] Step 2: Mix the isoprene rubber, resin-reinforced cis-butadiene rubber, trans-butadiene rubber, tear-resistant resin, carbon black, reactive plasticizer, antioxidant, modified phenolic resin, zinc oxide and stearic acid for 13 to 18 minutes to obtain a first-stage rubber.

[0047] Step 3: Mix the first section of rubber, pre-dispersed sulfur, accelerator and curing agent for 3 min to 5 min to obtain the high hardness and low dynamic-to-static ratio rubber material for motor suspension.

[0048] Compared with the prior art, the method for preparing high-hardness, low dynamic-to-static ratio rubber material for motor mounting provided in this application has the following advantages:

[0049] The preparation method provided in this application is reliable and controllable, which is conducive to its industrialization.

[0050] Optionally, in step one, the conditions for internal mixing are: initial temperature of 70℃~80℃, discharge temperature of 145℃~155℃, rotation speed of 30rpm~50rpm, and filling coefficient of 0.8.

[0051] By controlling the mixing conditions, the components are mixed evenly to form a homogeneous single-stage adhesive system.

[0052] Optionally, in step two, the mixing conditions are: initial temperature of 50℃~60℃, discharge temperature of 105℃~115℃, rotation speed of 30rpm~40rpm, and filling coefficient of 0.8.

[0053] By controlling the mixing conditions, a rubber material for motor suspension with excellent comprehensive performance, characterized by high hardness and low dynamic-to-static ratio, is formed. Detailed Implementation

[0054] 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.

[0055] Example 1

[0056] This invention provides a high-hardness, low dynamic-to-static ratio rubber material for motor mounting. The rubber material comprises the following components in parts by weight: isoprene rubber IR2200: 30 parts, resin-reinforced cis-butadiene rubber VCR412: 60 parts, trans-butadiene rubber: 10 parts, tear-resistant resin RT101A: 2 parts, carbon black: 30 parts, liquid isoprene rubber IR-563: 5 parts, antioxidant 4020: 1 part, antioxidant TMQ: 3 parts, modified phenolic resin ZY2000: 10 parts, curing agent HMMM: 0.6 parts, zinc oxide: 4 parts, stearic acid: 1.5 parts, pre-dispersed sulfur S-80: 1 part, and accelerator: 2 parts.

[0057] The preparation method of the above-mentioned high-hardness, low dynamic-to-static ratio rubber material for motor mounting includes the following steps:

[0058] Step 1: Weigh each component according to the raw materials listed above;

[0059] Step 2: The isoprene rubber, resin-reinforced cis-butadiene rubber, trans-butadiene rubber, tear-resistant resin, carbon black, reactive plasticizer, antioxidant, modified phenolic resin, zinc oxide and stearic acid are mixed for 16 minutes, with the initial temperature controlled at 80°C, the discharge temperature at 150°C, the rotation speed at 40 rpm, and the filling factor at 0.8, to obtain a first-stage rubber.

[0060] Step 3: Mix the first-stage rubber, pre-dispersed sulfur, accelerator and curing agent for 4 minutes, controlling the initial temperature to be 60℃, the discharge temperature to be 110℃, the rotation speed to be 35rpm and the filling coefficient to be 0.8, to obtain the high hardness low dynamic-to-static ratio rubber material for motor suspension.

[0061] Example 2

[0062] This invention provides a high-hardness, low dynamic-to-static ratio rubber material for motor mounting. The rubber material comprises the following components in parts by weight: isoprene rubber IR2200: 40 parts, resin-reinforced cis-butadiene rubber VCR412: 40 parts, trans-butadiene rubber: 20 parts, tear-resistant resin RT101A: 5 parts, carbon black: 20 parts, liquid isoprene rubber IR-563: 3 parts, antioxidant 4020: 2 parts, antioxidant TMQ: 1.5 parts, modified phenolic resin ZY2000: 16 parts, curing agent HTM: 1.5 parts, zinc oxide: 5 parts, stearic acid: 2 parts, pre-dispersed sulfur S-80: 2 parts, and accelerator: 3 parts.

[0063] The preparation method of the above-mentioned high-hardness, low dynamic-to-static ratio rubber material for motor mounting includes the following steps:

[0064] Step 1: Weigh each component according to the raw materials listed above;

[0065] Step 2: The isoprene rubber, resin-reinforced cis-butadiene rubber, trans-butadiene rubber, tear-resistant resin, carbon black, reactive plasticizer, antioxidant, modified phenolic resin, zinc oxide and stearic acid are mixed for 18 minutes, with the initial temperature controlled at 75°C, the discharge temperature at 155°C, the rotation speed at 30 rpm, and the filling factor at 0.8, to obtain a first-stage rubber.

[0066] Step 3: Mix the first-stage rubber, pre-dispersed sulfur, accelerator and curing agent for 3 minutes, controlling the initial temperature to be 55℃, the discharge temperature to be 105℃, the rotation speed to be 40rpm and the filling coefficient to be 0.8, to obtain the high hardness low dynamic-to-static ratio rubber material for motor suspension.

[0067] Example 3

[0068] This invention provides a high-hardness, low dynamic-to-static ratio rubber material for motor mounting. The rubber material comprises the following components in parts by weight: isoprene rubber IR2200: 55 parts, resin-reinforced cis-butadiene rubber VCR412: 40 parts, trans-butadiene rubber: 5 parts, tear-resistant resin RT101A: 3 parts, carbon black: 40 parts, liquid butadiene rubber: 10 parts, antioxidant 4020: 5 parts, antioxidant TMQ: 0.5 parts, modified phenolic resin ZY2000: 6 parts, curing agent HMMM: 1 part, zinc oxide: 6 parts, stearic acid: 3 parts, pre-dispersed sulfur S-80: 3.5 parts, and accelerator: 5 parts.

[0069] The preparation method of the above-mentioned high-hardness, low dynamic-to-static ratio rubber material for motor mounting includes the following steps:

[0070] Step 1: Weigh each component according to the raw materials listed above;

[0071] Step 2: The isoprene rubber, resin-reinforced cis-butadiene rubber, trans-butadiene rubber, tear-resistant resin, carbon black, reactive plasticizer, antioxidant, modified phenolic resin, zinc oxide and stearic acid are mixed for 13 minutes, with the initial temperature controlled at 70°C, the discharge temperature at 145°C, the rotation speed at 50 rpm, and the filling factor at 0.8, to obtain a first-stage rubber.

[0072] Step 3: Mix the first-stage rubber, pre-dispersed sulfur, accelerator and curing agent for 5 minutes, controlling the initial temperature at 50℃, the discharge temperature at 115℃, the rotation speed at 30 rpm and the filling coefficient at 0.8 to obtain the high hardness and low dynamic-to-static ratio rubber material for motor suspension.

[0073] To better illustrate the technical solution of the present invention, further comparisons are made below with comparative examples and embodiments of the present invention.

[0074] Comparative Example 1

[0075] This comparative example provides a high-hardness, low dynamic-to-static ratio rubber material for motor mounting, which differs from Example 1 in that the resin-reinforced cis-butadiene rubber VCR412 is replaced with cis-butadiene rubber.

[0076] Comparative Example 2

[0077] This comparative example provides a high-hardness, low dynamic-to-static ratio rubber material for motor mounting, which differs from Example 1 in that: resin-reinforced cis-butadiene rubber VCR412: 30 parts, trans-butadiene rubber: 30 parts.

[0078] Comparative Example 3

[0079] This comparative example provides a high-hardness, low dynamic-to-static ratio rubber material for motor mounting, which differs from Example 1 in that liquid isoprene rubber IR-563 is replaced with paraffin oil.

[0080] To better illustrate the characteristics of the rubber materials provided in the embodiments of the present invention, the performance of the rubber materials prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was tested, and the results are shown in Table 1 below.

[0081] Table 1

[0082] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Hardness HA 61 61 60 59 55 60 Tensile strength / MPa 18.9 18.3 18.5 12.7 15.3 18.3 Elongation at break / % 540 530 512 480 538 532 Static stiffness (N / mm) 247 242 245 240 243 239 Dynamic stiffness 100Hz N / mm 299 303 302 359 326 325 Dynamic-to-static ratio 1.21 1.25 1.23 1.49 1.34 1.36 Durability Index 100 102 100 63 83 90

[0083] Note: Durability score is 100.

[0084] As can be seen from Table 1, this application obtains a rubber material with a hardness of 60HA and a dynamic-to-static stiffness ratio of <1.30 at 100Hz through the synergistic effect between specific components. It also has excellent durability and mechanical properties such as tensile strength, overcoming the problem of difficulty in balancing high suspension stiffness and low dynamic-to-static ratio, and meeting the requirements for use of electric vehicle motor suspension rubber materials.

[0085] 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 or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-hardness, low dynamic-to-static ratio rubber material for motor suspension, characterized in that: The rubber material comprises the following components in parts by weight: isoprene rubber: 30-55 parts, resin-reinforced cis-butadiene rubber: 40-60 parts, trans-butadiene rubber: 5-20 parts, tear-resistant resin: 2-5 parts, carbon black: 20-40 parts, reactive plasticizer: 3-10 parts, antioxidant: 1.5-8 parts, modified phenolic resin: 6-16 parts, curing agent: 0.6-1.5 parts, zinc oxide: 4-6 parts, stearic acid: 1.5-3 parts, pre-dispersed sulfur: 1.0-3.5 parts, and accelerator: 2-5 parts. The resin-reinforced cis-butadiene rubber is of type VCR412; The type of the tear-resistant resin is RT101A; The butadiene content in the trans-butadiene rubber is 5wt%~30wt%; The modified phenolic resin is cashew oil modified phenolic resin; The reactive plasticizer is a polydiolefin or diene copolymer low molecular weight polymer, and the number average molecular weight of the plasticizer is 500~10000.

2. The high-hardness, low dynamic-to-static ratio rubber material for motor mounting as described in claim 1, characterized in that: The carbon black has a particle size of 40 nm to 125 nm; and / or The curing agent is hexamethylenetetramine or hexamethoxymethylmelamine; and / or The pre-dispersed sulfur uses styrene-butadiene rubber as a carrier and has a sulfur content of 78wt%~82wt%.

3. The high-hardness, low dynamic-to-static ratio rubber material for motor mounting as described in claim 1, characterized in that: The antioxidant is a ketone-amine reaction product and a p-phenylenediamine antioxidant with a mass ratio of 0.5~3:1~5.

4. The high-hardness, low dynamic-to-static ratio rubber material for motor mounting as described in claim 3, characterized in that: The reactive plasticizer is liquid isoprene rubber or liquid butadiene rubber; and / or The ketone-amine reaction product is the antioxidant TMQ; and / or The p-phenylenediamine antioxidant is antioxidant 6PPD.

5. A method for preparing a high-hardness, low dynamic-to-static ratio rubber material for motor suspension, characterized in that: Includes the following steps: Step 1: Weigh each component according to the raw materials described in any one of claims 1 to 4; Step 2: Mix the isoprene rubber, resin-reinforced cis-butadiene rubber, trans-butadiene rubber, tear-resistant resin, carbon black, reactive plasticizer, antioxidant, modified phenolic resin, zinc oxide and stearic acid for 13-18 minutes to obtain a first-stage rubber. Step 3: Mix the first section of rubber, pre-dispersed sulfur, accelerator and curing agent for 3 min to 5 min to obtain the high hardness and low dynamic-to-static ratio rubber material for motor suspension.

6. The method for preparing the high-hardness, low-dynamic-to-static ratio rubber material for motor suspension as described in claim 5, characterized in that: In step one, the conditions for intensive mixing are: initial temperature of 70℃~80℃, discharge temperature of 145℃~155℃, rotation speed of 30rpm~50rpm, and filling factor of 0.8; and / or In step two, the mixing conditions are as follows: initial temperature of 50℃~60℃, discharge temperature of 105℃~115℃, rotation speed of 30rpm~40rpm, and filling coefficient of 0.8.

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