Rubber composite material filled with micromolecular coupling agent modified carbon black as well as preparation method and application of rubber composite material

Abstract

The invention relates to a rubber composite material filled with small-molecule coupling agent modified carbon black as well as a preparation method and application of the rubber composite material. The rubber composite material is prepared from raw materials including unsaturated rubber, carbon black, a coupling agent and sulfur, and the coupling agent is 4, 4 '-diaminodiphenyl disulfide. According to the invention, the carbon black is modified by adopting the micromolecular coupling agent, the modification effect is better than that of the traditional silane coupling agent and polymer coupling agent, the rolling resistance of the carbon black-rubber composite material can be obviously reduced, and good wear resistance can be maintained.

Description

Technical Field

[0001] This invention relates to the field of rubber formulation and processing, and more specifically, to a small molecule coupling agent modified carbon black-filled rubber composite material, its preparation method, and its application. Background Technology

[0002] With the increasing attention given to new energy vehicles, the development of low rolling resistance tires is needed to alleviate the current "range anxiety" problem. New energy vehicles are heavier, have faster acceleration, and higher driving torque, resulting in a 100% increase in tire wear rate, placing higher demands on tire wear resistance that ordinary "green tires" cannot meet. Furthermore, for products with even more demanding service conditions, such as aircraft tires and heavy-duty truck tires, carbon black systems are irreplaceable. Therefore, preparing carbon black-filled tread compound materials that combine low rolling resistance and good wear resistance is key to developing high-performance tires.

[0003] Carbon black, a widely used nano-reinforcing filler in the rubber industry, can significantly improve the tensile, tear strength, and abrasion resistance of rubber composites. However, carbon black has a strong structure and is prone to agglomeration in the rubber matrix, resulting in high rolling resistance and increased compression fatigue temperature, which is detrimental to the overall performance of rubber products. Therefore, chemically modifying carbon black with coupling agents to promote its dispersion in the rubber matrix is ​​a key and breakthrough point for reducing the rolling resistance and balancing the abrasion resistance of carbon black-filled rubber composites.

[0004] Commonly used silane coupling agents have limited effectiveness in modifying carbon black. For example, in the literature "Interfacial Regulation and Wear Resistance of Carbon Black / Natural Rubber Composites," the use of silane coupling agent Si69 to modify carbon black reduced rolling resistance but also significantly decreased wear resistance, without improving the overall performance of the tread rubber. This is mainly due to the strong physical interaction between carbon black and rubber. Commonly used silane coupling agents and currently reported macromolecular coupling agents can "shield" this strong physical interaction, leading to a decrease in wear resistance. Therefore, this invention proposes a method for modifying carbon black using small-molecule coupling agents to prepare rubber composites that balance low rolling resistance and good wear resistance. Summary of the Invention

[0005] This invention primarily addresses the shortcomings of existing technologies, such as poor dispersion of carbon black in a rubber matrix, high rolling resistance, and high heat generation, while maintaining good wear resistance in the composite material. Therefore, a modifier that is simple to operate, effectively promotes carbon black dispersion, and does not hinder the strong physical interaction between carbon black and rubber is proposed. Furthermore, a formulation and processing technology are designed to effectively reduce rubber rolling resistance and dynamic heat generation while maintaining good wear resistance.

[0006] One objective of this invention is to provide a rubber composite material filled with carbon black modified by a small molecule coupling agent.

[0007] The rubber composite material is prepared from raw materials containing the following components, in parts by weight:

[0008]

[0009] The coupling agent, APDS (4,4'-diaminodiphenyl disulfide), is a small molecule coupling agent with the structure shown in formula (1):

[0010]

[0011] The amount of the coupling agent can be 0.3 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.5 parts, 1.8 parts, 2 parts, 2.5 parts, etc.

[0012] More preferably, the coupling agent accounts for 2% to 4% of the mass fraction of carbon black, such as 2%, 2.5%, 3%, 4%, etc.

[0013] The unsaturated rubber is preferably selected from one or more of the following: natural rubber, solution-polymerized styrene-butadiene rubber, cis-butadiene rubber, and isoprene rubber.

[0014] The carbon black is selected from at least one of the following: ultra-abrasion resistant furnace black, medium-ultra-abrasion resistant furnace black, high-abrasion resistant furnace black, and general-purpose furnace black.

[0015] This invention can also add various commonly used additives in the field, including but not limited to zinc oxide, stearic acid, accelerators, antioxidants, and paraffin, according to processing needs. The dosage of these additives is the conventional dosage, or can be flexibly adjusted according to actual needs.

[0016] Preferably, based on 100 parts by weight of unsaturated rubber, the amount of the above additives is as follows:

[0017]

[0018] There are no particular limitations on accelerators and antioxidants; conventional additives in this field, such as accelerator CZ, antioxidant RD, and antioxidant 4020, can be used.

[0019] The second objective of this invention is to provide a method for preparing a rubber composite material filled with carbon black modified by the small molecule coupling agent, comprising the following steps: mixing the components, heat preservation treatment, kneading, and vulcanizing to obtain the rubber composite material.

[0020] In the preparation process of this invention, the mixing, compounding, open milling, and vulcanization of the raw material components can adopt conventional rubber processing techniques in the prior art. The equipment used is also equipment commonly used in rubber processing in the prior art, such as kneaders, internal mixers, open mills, vulcanizing machines, etc.

[0021] Preferably, the preparation method includes the following steps:

[0022] (1) Mix the components, including unsaturated rubber, carbon black and coupling agent, evenly and heat-insulate them;

[0023] (2) Add sulfur and optional additives, and mix.

[0024] (3) Sulfation.

[0025] Preferably, in step (1), after mixing evenly, the mixture is kept at 100-155°C and stirred for 3-15 minutes, more preferably at 145-155°C and stirred for 3-10 minutes. For example, the holding temperature can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 155°C, etc.; the holding time can be 3 minutes, 5 minutes, 8 minutes, 10 minutes, 15 minutes, etc.

[0026] A third objective of this invention is to provide the application of the small molecule coupling agent-modified carbon black-filled rubber composite material or the rubber composite material obtained by the preparation method in tire materials.

[0027] This invention utilizes the reaction of amino groups in the structure of the small-molecule coupling agent APDS with oxygen-containing functional groups such as carboxyl groups on the carbon black surface to form chemical bonds. The disulfide bonds in the coupling agent structure are broken during heat treatment, allowing them to form covalent bonds with the rubber, enhancing the chemical interaction between carbon black and rubber and reducing friction between them under dynamic conditions. Unlike the literature "Interfacial Regulation and Wear Resistance Study of Carbon Black / Natural Rubber Composites," which uses polymers to form a coating structure on the carbon black surface, although this promotes the dispersion of carbon black in the rubber matrix, it significantly affects the strong physical interactions, resulting in severe loss of wear resistance and poor modification effect of polymer coupling agents. The small-molecule coupling agent APDS in this invention does not "shield" the strong physical interactions between carbon black and rubber. The dispersibility of carbon black is effectively improved, and rolling resistance is significantly reduced. Because the strong physical interactions between carbon black and rubber are well preserved, the wear resistance of the composite material is improved while reducing rolling resistance.

[0028] This invention uses the small molecule coupling agent APDS to modify carbon black, which is superior to the modification effect of traditional silane coupling agents and polymer coupling agents. It can significantly reduce the rolling resistance of carbon black-rubber composites while maintaining good wear resistance. Detailed Implementation

[0029] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0030] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0031] Unless otherwise specified, the raw materials used in the examples and comparative examples are all publicly available in the prior art, such as those that are readily available or prepared using methods disclosed in the prior art. The carbon black used is ultra-abrasion resistant furnace black N134.

[0032] According to a preferred embodiment of the present invention, the rubber composite material is prepared by the following steps:

[0033] (1) Add the components including 100 parts of unsaturated rubber, 30-60 parts of carbon black, and 0.3-2.5 parts of coupling agent APDS to the rubber mixing equipment and mix evenly. Keep warm at 100-155℃ and stir for 3-15 minutes.

[0034] (2) Add the product of step (1) and the remaining components (sulfur, and optional additives such as zinc oxide, stearic acid, accelerator, antioxidant, paraffin, etc.) to a two-roll mill until they are mixed evenly to prepare a compound rubber.

[0035] (3) Prepare vulcanized rubber products according to the rubber vulcanization process.

[0036] Example 1:

[0037] The compound consists of 100 parts by weight of natural rubber, 50 parts of carbon black, and 1.0 part of coupling agent APDS. Other components include 5 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of accelerator CZ, 1.5 parts of sulfur, 1.5 parts of antioxidant RD, 1.5 parts of antioxidant 4020, and 1 part of paraffin wax. The process is as follows: First, 100 parts of natural rubber are added to a mixer for blending. Then, carbon black and APDS are added in three equal portions at 100°C, mixed thoroughly. The mixture is then heated to 150°C and heat-treated for 5 minutes. After cooling to room temperature, the blend, zinc oxide, stearic acid, accelerator, antioxidant, sulfur, and paraffin wax are blended together to prepare the compound. The compound is then vulcanized on a flat vulcanizing machine at 140°C and 15 MPa for the normal vulcanization time. Finally, the physical and mechanical properties and dynamic mechanical properties of the vulcanized rubber are tested.

[0038] Example 2:

[0039] The compound consists of 100 parts by weight of natural rubber, 50 parts by weight of carbon black, and 1.5 parts by weight of coupling agent APDS. Other components include 5 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 1.5 parts by weight of accelerator CZ, 1.5 parts by weight of sulfur, 1.5 parts by weight of antioxidant RD, 1.5 parts by weight of antioxidant 4020, and 1 part by weight of paraffin wax. The process is as follows: First, 100 parts of natural rubber are added to a mixer for blending. Then, carbon black and coupling agent APDS are added in three equal portions at 100°C, mixed thoroughly. The mixture is then heated to 150°C and heat-treated for 5 minutes. After cooling to room temperature, the blend, zinc oxide, stearic acid, accelerator, antioxidant, sulfur, and paraffin wax are blended together to prepare the compound. The compound is then vulcanized on a flat vulcanizing machine at 140°C and 15 MPa for the normal vulcanization time. Finally, the physical and mechanical properties and dynamic mechanical properties of the vulcanized rubber are tested.

[0040] Example 3:

[0041] The compound consists of 100 parts by weight of natural rubber, 50 parts of carbon black, and 2.5 parts of coupling agent APDS. Other components include 5 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of accelerator CZ, 1.5 parts of sulfur, 1.5 parts of antioxidant RD, 1.5 parts of antioxidant 4020, and 1 part of paraffin wax. The process is as follows: First, 100 parts of natural rubber are added to a mixer for blending. Then, carbon black and APDS are added in three equal portions at 100°C, mixed thoroughly. The mixture is then heated to 150°C and heat-treated for 5 minutes. After cooling to room temperature, the blend, zinc oxide, stearic acid, accelerator, antioxidant, sulfur, and paraffin wax are blended together to prepare the compound. The compound is then vulcanized on a flat vulcanizing machine at 140°C and 15 MPa for the normal vulcanization time. Finally, the physical and mechanical properties and dynamic mechanical properties of the vulcanized rubber are tested.

[0042] Example 4:

[0043] The composition consists of 100 parts by weight of natural rubber, 50 parts of carbon black, and 1.5 parts of coupling agent APDS. Other components include 5 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of accelerator CZ, 1.5 parts of sulfur, 1.5 parts of antioxidant RD, 1.5 parts of antioxidant 4020, and 1 part of paraffin wax. The process is as follows: First, 100 parts of natural rubber are added to a mixer for blending. Then, carbon black and coupling agent APDS are divided into three equal parts and added in three separate additions, mixed thoroughly at 100°C, and the mixture is discharged and cooled to room temperature. The cooled blend, zinc oxide, stearic acid, accelerator, antioxidant, sulfur, and paraffin wax are then blended to prepare the compound. The compound is vulcanized on a flat vulcanizing machine at 140°C and 15 MPa for the normal vulcanization time. Finally, the physical and mechanical properties and dynamic mechanical properties of the vulcanized rubber are tested.

[0044] Comparative Example 1:

[0045] The mixture contains 100 parts by weight of natural rubber and 50 parts by weight of carbon black. Other components include: 5 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 1.5 parts by weight of accelerator CZ, 1.5 parts by weight of sulfur, 1.5 parts by weight of antioxidant RD, 1.5 parts by weight of antioxidant 4020, and 1 part by weight of paraffin wax. The process is as follows: First, 100 parts by weight of natural rubber are added to a mixer for blending. Then, carbon black is divided into 3 equal parts and added in 3 batches, mixed evenly at 100℃. The mixture is then heated to 150℃ and heat-treated for 5 minutes. After cooling to room temperature, the blend, zinc oxide, stearic acid, accelerator, antioxidant, sulfur, and paraffin wax are blended together to prepare the compound. The compound is then vulcanized on a flat vulcanizing machine at 140℃ and 15MPa for the normal vulcanization time. Finally, the physical and mechanical properties and dynamic mechanical properties of the vulcanized rubber are tested.

[0046] Comparative Example 2:

[0047] The compound consists of 100 parts by weight of natural rubber, 50 parts of carbon black, and 3.0 parts of Si69 silane coupling agent. Other components include 5 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of accelerator CZ, 1.5 parts of sulfur, 1.5 parts of antioxidant RD, 1.5 parts of antioxidant 4020, and 1 part of paraffin wax. The process is as follows: First, 100 parts of natural rubber are added to a mixer for blending. Then, carbon black and Si69 silane coupling agent are added in three equal portions at 100°C, mixed thoroughly. The mixture is then heated to 150°C and heat-treated for 5 minutes. After cooling to room temperature, the blend, zinc oxide, stearic acid, accelerator, antioxidant, sulfur, and paraffin wax are blended together to prepare the compound. The compound is then vulcanized on a flat vulcanizing machine at 140°C and 15 MPa for the normal vulcanization time. Finally, the physical and mechanical properties and dynamic mechanical properties of the vulcanized rubber are tested.

[0048] Table 1. Performance of each embodiment and comparative example

[0049]

[0050] Note:

[0051] (1) RPA G'@1.0% is the storage modulus of the compound at 1.0% shear strain, used to study the viscoelasticity of carbon black / rubber compounds. A smaller value indicates better dispersibility of carbon black.

[0052] (2) Tensile strength properties were measured according to the national standard GB / T 528-2009. High tensile strength of vulcanized rubber indicates that there are fewer carbon black aggregates in the rubber matrix, which reduces the number of stress concentration areas, improves the reinforcing effect of carbon black on rubber, and strengthens the interaction between filler and rubber.

[0053] (3) Tanδ@60℃ is the loss tangent of vulcanized rubber under dynamic load at 60℃. It can usually be used to evaluate the rolling resistance of rubber. The smaller the value, the smaller the energy loss caused by internal friction of rubber composite material, and the lower the rolling resistance of composite material.

[0054] (4) Compression fatigue temperature rise is the temperature rise at the bottom of the vulcanized rubber sample when the mold cavity temperature is 55℃, the sample is preheated for 30 minutes, the load is 25kg, the stroke is 4.45mm, the loading frequency is 30Hz, the test time is 25min. The value is directly related to the mutual friction between all components of the carbon black / rubber composite material. The smaller the value, the stronger the interaction force between the filler and the rubber, the smaller the friction between filler and filler and between filler and rubber, and the lower the dynamic heat generation of the product.

[0055] (5) The abrasion resistance index was tested using a LAT-100 abrasion testing machine from Veluwse Machine Industrie, Netherlands, under test conditions of 75 N load, 25 km / h speed, 15° slip angle, and 250 m distance. Using Comparative Example 1 as a reference, the abrasion resistance index (ARI) was calculated using equation (2):

[0056]

[0057] In equation (2), Vr and Vt represent the wear volume of the reference sample and the test sample, respectively. The higher the abrasion resistance index, the better the abrasion resistance of the rubber composite material.

[0058] As shown in Table 1 above, compared with the unmodified carbon black-filled rubber composite material in Comparative Example 1, the results, combined with different embodiments, indicate that the small molecule coupling agent APDS can effectively improve the dispersibility of carbon black in the rubber compound without shielding the strong physical interaction between carbon black and rubber. The reinforcing effect of carbon black on rubber is enhanced, tensile strength increases, rolling resistance and compression fatigue temperature rise decrease, wear resistance remains good, and the dynamic properties of the rubber are excellent. In Comparative Example 2, although modifying carbon black with a common silane coupling agent can promote carbon black dispersion to a certain extent and reduce rolling resistance and compression fatigue temperature rise, the mechanical properties decrease, and the wear resistance is severely compromised, resulting in a significant decline in the overall performance of the rubber composite material.

[0059] The results above show that the APDS coupling agent provided by this invention has a significantly improved modification effect compared with the commonly used silane coupling agent. Moreover, it can significantly improve the static mechanical properties and dynamic properties of carbon black-rubber composites with a small dosage, and has good application prospects.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A small molecule coupling agent modified carbon black-filled rubber composite material, prepared from raw materials containing the following components, in parts by weight: in, The coupling agent is 4,4'-diaminodiphenyldisulfide.

2. The rubber composite material according to claim 1, characterized in that... It is prepared from raw materials containing the following components, in parts by weight:

3. The rubber composite material according to claim 1, characterized in that: The unsaturated rubber is selected from at least one of natural rubber, solution-polymerized styrene-butadiene rubber, cis-butadiene rubber, and isoprene rubber.

4. The rubber composite material according to claim 1, characterized in that: The carbon black is selected from at least one of the following: ultra-abrasion resistant furnace black, medium-ultra-abrasion resistant furnace black, high-abrasion resistant furnace black, and general-purpose furnace black.

5. The rubber composite material according to claim 1, characterized in that: The rubber composite material includes at least one of the following additives: zinc oxide, stearic acid, accelerator, antioxidant, and paraffin.

6. The rubber composite material according to claim 5, characterized in that... Based on 100 parts by weight of the unsaturated rubber, the rubber composite material comprises:

7. A method for preparing a rubber composite material according to any one of claims 1 to 6, comprising mixing the components, heat preservation treatment, compounding, and vulcanization to obtain the rubber composite material.

8. The preparation method according to claim 7, characterized in that... Includes the following steps: (1) Mix the components, including unsaturated rubber, carbon black and coupling agent, evenly and heat-insulate them; (2) Add sulfur and optional additives, and mix. (3) Sulfation.

9. The preparation method according to claim 8, characterized in that: In step (1), after mixing evenly, keep warm at 100-155℃ and stir for 3-15 minutes, preferably at 145-155℃ and stir for 3-10 minutes.

10. The application of the rubber composite material according to any one of claims 1 to 6 or the rubber composite material obtained by the preparation method according to any one of claims 7 to 9 in tire materials.

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