Cutting-resistant low-heat-generation engineering tire tread rubber based on composite reinforcing system and preparation method of cutting-resistant low-heat-generation engineering tire tread rubber

Abstract

The invention discloses anti-cutting low-heat engineering tire tread rubber based on a composite reinforcing system and a preparation method thereof, and relates to the technical field of tread rubber. According to the technical scheme, the rubber material is prepared from the following components in parts by weight: 0 to 40 parts of natural rubber, 60 to 100 parts of tear-resistant modified rubber NRX-N1, 10 to 20 parts of HT carbon silicon enhancer, 40 to 50 parts of carbon black, 3 to 5 parts of zinc oxide, 1 to 2 parts of stearic acid, 2 to 4 parts of anti-aging agent, 1 to 2 parts of microcrystalline wax, 1.5 to 2.5 parts of sulfur, 0.5 to 1 part of accelerant 833 and 0.5 to 1.5 parts of sulfenamide accelerant. According to the invention, the tear-resistant modified glue NRX-N1, the HT carbon silicon reinforcing agent and the specific alkaline accelerant 833 are innovatively and synergistically compounded, a unique'fiber reinforcement-nano reinforcement-vulcanization network optimization 'composite system is constructed, and a remarkable breakthrough in performance is realized.

Description

Technical Field

[0001] This invention relates to the field of tread compound technology, specifically to a cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system and its preparation method. Background Technology

[0002] Construction machinery tires (such as mining dump truck and loader tires) serve in extremely harsh environments such as open-pit mines and large construction sites, enduring huge loads, impacts and cuts from sharp materials, and periodic flexural strain caused by high-speed rolling. These demanding working conditions place extremely high demands on the performance of the tread compound: on the one hand, it needs extremely high cut and tear resistance to prevent tread chipping and puncture damage; on the other hand, the compound needs to have low dynamic heat generation to avoid accelerated aging, decreased physical properties, or even serious failures such as delamination and tire blowouts due to heat accumulation.

[0003] Traditional techniques for improving the wear resistance and cut resistance of tire treads typically employ methods such as high-filler carbon black, the addition of short fibers, or the use of high-strength synthetic rubber. However, these methods often introduce new problems: high-filler carbon black leads to a significant increase in heat generation in the rubber compound, resulting in increased rolling resistance; short fibers are difficult to disperse, easily causing stress concentration, and offer limited improvement in heat generation; high-strength synthetic rubber is expensive, and its compatibility and processability with natural rubber may be poor. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of existing engineering tire tread rubbers, which cannot simultaneously achieve high cut resistance and low dynamic heat generation, and have poor dynamic durability. This invention provides a cut-resistant and low-heat-generating engineering tire tread rubber based on a composite reinforcement system and its preparation method. Through innovative material combination and synergistic mechanism, a breakthrough in the comprehensive performance of the tread rubber is achieved.

[0005] The technical solution of this invention is as follows: On one hand, the present invention provides a cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system, comprising the following components by weight: 0-40 parts natural rubber, 60-100 parts tear-resistant modified rubber NRX-N1, 10-20 parts HT carbon silicon reinforcing agent, 40-50 parts carbon black, 3-5 parts zinc oxide, 1-2 parts stearic acid, 2-4 parts antioxidant, 1-2 parts microcrystalline wax, 1.5-2.5 parts sulfur, 0.5-1 part accelerator 833, and 0.5-1.5 parts sulfenamide accelerator.

[0006] Among them, the tear-resistant modified rubber NRX-N1 (Qingdao Jinruina Rubber Technology Co., Ltd.) is a natural latex composite rubber containing 1 wt.% modified short fibers. HT carbon silicon reinforcing agent (Anhui Guruit New Material Technology Co., Ltd.) is a silicon-based nanomaterial with a DBP oil absorption value ≥25×10⁻⁶. -5 m3 / kg, specific surface area ≤20m² 2 / g. Accelerator 833 (DuPont, USA) is a butyraldehyde-butylamine condensate, a strongly alkaline accelerator that can effectively improve the mechanical properties and aging resistance of vulcanized rubber.

[0007] Preferably, the carbon black is N220 or N115.

[0008] Preferably, the antioxidant is antioxidant 4020 and antioxidant RD.

[0009] Preferably, the sulfenamide accelerator is accelerator NS (N-tert-butyl-2-benzothiazole sulfenamide) or CZ (N-cyclohexyl-2-benzothiazole sulfenamide).

[0010] On the other hand, the present invention provides a method for preparing the above-mentioned cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system, comprising the following steps: S1 Mixing Natural rubber, tear-resistant modified rubber NRX-N1, carbon black, zinc oxide, stearic acid, antioxidant and microcrystalline wax are put into an internal mixer and mixed at a speed of 38-42 rpm. The mixture is lifted and pressed every 30-35 seconds. When the temperature of the rubber compound reaches 160-165℃, the rubber is discharged and sheeted. After cooling at room temperature for 4-6 hours, a masterbatch is obtained. S2 Second Stage Mixing The first stage masterbatch from step S1 and the HT silicon carbide reinforcing agent are put into a mixer and mixed at a speed of 34-37 rpm. The mixture is lifted and pressed every 30-35 seconds. When the temperature of the rubber compound reaches 150-155℃, the rubber is discharged and sheeted. After cooling at room temperature for 4-6 hours, the second stage masterbatch is obtained. The second stage masterbatch needs to be returned to the mixer for re-mixing, and then the final mixing is carried out. S3 Final Refinement The second-stage masterbatch after step S2 remelting, along with sulfur, accelerator 833, and sulfenamide accelerator, are put into an internal mixer and mixed at a speed of 27-30 rpm. The mixture is then lifted and pressed at intervals of 30 s, 25 s, and 20 s. When the mixing time reaches 110-120 s, the rubber is discharged and sheeted. After cooling, the cut-resistant, low-heat-generating engineering tire tread rubber based on the composite reinforcement system is obtained.

[0011] Compared with the prior art, the present invention has the following advantages: This invention innovatively combines the tear-resistant modified rubber NRX-N1, HT silicon carbide reinforcing agent, and a specific alkaline accelerator 833 in a synergistic compound to construct a unique "fiber reinforcement-nano-reinforcement-vulcanization network optimization" composite system, achieving a significant performance breakthrough: the modified short fibers in NRX-N1 form a three-dimensional rigid skeleton in the rubber compound, providing an excellent foundation for cut and tear resistance. The HT silicon carbide reinforcing agent, as a low-structure nanofiller, effectively fills the voids in the fiber network, improves stress distribution, and significantly reduces dynamic heat generation in the rubber compound. Accelerator 833, in synergy with sulfenamide accelerators, optimizes the vulcanization network and interfacial bonding, improves crosslinking uniformity, further reduces internal friction, and increases dynamic fatigue life. Ultimately, the engineering tire tread rubber of this invention achieves a balance between cut resistance, low heat generation, and dynamic durability, with a significant improvement in overall performance, effectively resolving the contradiction of traditional engineering tire tread rubbers being unable to simultaneously achieve all performance goals. Detailed Implementation

[0012] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0013] Examples 1-3 and Comparative Examples 1-7 The tread compound formulations for Examples 1-3 and Comparative Examples 1-7 are shown in Table 1: Table 1. Tread compound formulations for Examples 1-3 and Comparative Examples 1-7

[0014] The preparation methods of the tread rubber in Examples 1-3 and Comparative Examples 1-7 include the following steps: S1 Mixing All rubber components, carbon black N220, zinc oxide, stearic acid, antioxidant 4020, antioxidant RD and microcrystalline wax are put into an internal mixer and mixed at a speed of 42 rpm. The mixture is lifted and pressed every 30 seconds. When the rubber temperature reaches 160℃, the rubber is discharged and sheeted. After cooling at room temperature for 6 hours, a first-stage masterbatch is obtained, which is then mixed in a second stage. S2 Second Stage Mixing The first stage masterbatch from step S1 and HT silicon carbide reinforcing agent or silica are put into an internal mixer and mixed at 37 rpm. The mixture is lifted and pressed every 30 seconds. When the temperature of the rubber compound reaches 150°C, the rubber is discharged and sheeted. After cooling at room temperature for 6 hours, the second stage masterbatch is obtained. The second stage masterbatch needs to be returned to the mixer for re-mixing, and then the final mixing is carried out. S3 Final Refinement The second-stage masterbatch after step S2 remelting, along with sulfur and accelerator, is put into an internal mixer and mixed at 27 rpm. The mixture is then lifted and pressed at intervals of 30 s, 25 s, and 20 s. When the mixing time reaches 120 s, the rubber is discharged and sheeted. After cooling, the cut-resistant, low-heat-generating engineering tire tread rubber is obtained.

[0015] The tread rubbers prepared in Examples 1-3 and Comparative Examples 1-7 were subjected to high-temperature vulcanization and then their performance was tested. The test results are shown in Table 2. Table 2 Performance test results of tread rubbers in Examples 1-3 and Comparative Examples 1-7

[0016] Note: The high-temperature vulcanization sample preparation conditions were 145℃×40min; the cut resistance index was compared with Comparative Example 1 (1.00).

[0017] As shown in Table 2, Example 1 uses a combination of three materials: tear-resistant modified adhesive NRX-N1, HT silicon carbide reinforcing agent, and accelerator 833. Compared with Comparative Example 1, the strength of the adhesive is not significantly different, but the cut resistance and abrasion resistance are significantly improved, increasing by about 30% and 23.1% respectively. At the same time, the heat generation and aging resistance of the adhesive are also improved, with heat generation reduced by about 13% and aging resistance improved by about 8%.

[0018] Meanwhile, compared to Comparative Example 2, which only added the tear-resistant modified adhesive NRX-N1, Example 1, while maintaining similar cut resistance, showed a significant reduction in dynamic heat generation and improved aging resistance. This indicates that while using fiber reinforcement alone helps with cut resistance, it exacerbates dynamic heat generation. Compared to Comparative Example 3, which only added HT silicon carbide reinforcement, Example 1 showed improvements in both tensile strength and cut resistance, indicating that while nanofillers are beneficial for reducing heat generation, their self-reinforcing capacity is limited and they need to be used in conjunction with fiber reinforcement to meet the requirements of high strength and high cut resistance. Compared to Comparative Example 4, which only added accelerator 833, both showed comparable aging resistance, but Example 1 demonstrated significant advantages in cut resistance and low heat generation.

[0019] Compared to Comparative Example 5, which simultaneously added the tear-resistant modified adhesive NRX-N1 and HT silicon carbide reinforcement, Example 1 exhibited superior aging resistance while maintaining similar cut resistance and low heat generation. This indicates that although the physical synergy between NRX-N1 and HT silicon carbide reinforcement can improve cut resistance and heat generation, the lack of chemical optimization of the crosslinking network by accelerator 833 makes it difficult to achieve long-term thermo-oxidative stability. Compared to Comparative Example 6, which simultaneously added NRX-N1 and accelerator 833, Example 1 showed a significant reduction in dynamic heat generation under similar cut resistance conditions. This demonstrates that, based on the combination of fiber reinforcement and network optimization, the introduction of HT silicon carbide reinforcement with unique low hysteresis characteristics plays a crucial role in further reducing the dynamic heat generation of the adhesive. Compared to Comparative Example 7, which simultaneously added HT silicon carbide reinforcement and accelerator 833, Example 1 significantly improved cut resistance while maintaining low heat generation and good aging resistance. This proves that even with the combination of functional fillers and network optimizers, the cut resistance of the compound still cannot meet the requirements without the fiber-reinforced skeleton provided by NRX-N1.

[0020] As can be seen from the above comparison, compared with the rubber compound that adds one or two of the following materials, namely the tear-resistant modified adhesive NRX-N1, HT silicon carbide reinforcing agent and accelerator 833, the rubber compound of Example 1, which adds all three materials at the same time, shows a more obvious advantage.

[0021] In summary, by simultaneously adding tear-resistant modified adhesive NRX-N1, HT carbon silicon reinforcing agent, and accelerator 833, this invention essentially constructs a multi-scale, multi-level integrated composite system of "reinforcement-thermal conductivity-crosslinking".

[0022] At the reinforcement level, the modified short fibers in the tear-resistant modified rubber NRX-N1 serve as a macroscopic reinforcing phase. Through physical entanglement and mechanical interlocking, they effectively inhibit crack initiation and propagation when the rubber compound is subjected to external forces (especially cutting and impact). This is the main physical basis for achieving high cut resistance.

[0023] In terms of thermal conductivity and dynamic performance optimization, HT silicon carbide reinforcing agent, as a nanoscale filler, has two major functions due to its low structure and high specific surface area: first, it acts as a high thermal conductivity channel to accelerate heat dissipation during dynamic deformation; second, as a flexible filler particle, it directly reduces the viscoelastic loss (tan δ) of the adhesive through its own low hysteresis characteristics, which is the key to achieving low compression temperature rise.

[0024] At the level of chemical crosslinking and interface stabilization, accelerator 833, as a strong alkaline additive, plays a dual role in the vulcanization process: first, it regulates the reaction kinetics of the sulfur-accelerator system, promotes the formation of a polysulfide crosslinking network with better thermal stability, and improves the heat aging resistance of the matrix; second, its alkaline environment and possible coordination effect strengthen the chemical-physical interaction between rubber molecular chains and short fiber surfaces, as well as between rubber and filler surfaces such as carbon black / HT silicon carbide reinforcing agents, thereby optimizing the stress transfer efficiency between the reinforcing phase, filler phase and rubber matrix, and improving the uniformity and durability of the overall structure.

[0025] These three components do not work independently, but rather form a synergistic network of "physical reinforcement - functional filling - chemical bonding". The addition of HT carbosilicon reinforcing agent optimizes the dispersion of short fibers in the compound, reducing stress concentration caused by fiber agglomeration; simultaneously, its surface properties, combined with the crosslinking network optimized by accelerator 833, further strengthen the interface between the filler and the matrix. Conversely, the uniformly dispersed fiber skeleton provides a stable support structure for the entire system, enabling the optimized crosslinking network and filling system to maintain more stable performance under dynamic loads. This multi-scale, multi-mechanism synergistic effect ultimately improves the compatibility of the compound in multiple performance indicators such as mechanical strength, resistance to dynamic fatigue, heat generation control, and aging resistance.

Claims

1. A cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system, characterized in that, By weight, it comprises the following components: 0-40 parts natural rubber, 60-100 parts tear-resistant modified rubber NRX-N1, 10-20 parts HT carbon silicon reinforcing agent, 40-50 parts carbon black, 3-5 parts zinc oxide, 1-2 parts stearic acid, 2-4 parts antioxidant, 1-2 parts microcrystalline wax, 1.5-2.5 parts sulfur, 0.5-1 part accelerator 833, and 0.5-1.5 parts sulfenamide accelerator.

2. The cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system as described in claim 1, characterized in that, The carbon black is N220 or N115.

3. The cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system as described in claim 1, characterized in that, The antioxidants are antioxidant 4020 and antioxidant RD.

4. The cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system as described in claim 1, characterized in that, The sulfonamide accelerator is accelerator NS or CZ.

5. The method for preparing the cut-resistant, low-heat-generating engineering tire tread compound based on a composite reinforcement system as described in any one of claims 1-4, characterized in that, Includes the following steps: S1 Mixing Natural rubber, tear-resistant modified rubber NRX-N1, carbon black, zinc oxide, stearic acid, antioxidant and microcrystalline wax are put into an internal mixer and mixed at a speed of 38-42 rpm. The mixture is lifted and pressed every 30-35 seconds. When the temperature of the rubber compound reaches 160-165℃, the rubber is discharged and sheeted. After cooling at room temperature for 4-6 hours, a masterbatch is obtained. S2 Second Stage Mixing The first stage masterbatch from step S1 and the HT silicon carbide reinforcing agent are put into a mixer and mixed at a speed of 34-37 rpm. The mixture is lifted and pressed every 30-35 seconds. When the temperature of the rubber compound reaches 150-155℃, the rubber is discharged and sheeted. After cooling at room temperature for 4-6 hours, the second stage masterbatch is obtained. The second stage masterbatch needs to be returned to the mixer for re-mixing, and then the final mixing is carried out. S3 Final Refinement The second-stage masterbatch after step S2 remelting, along with sulfur, accelerator 833, and sulfenamide accelerator, are put into an internal mixer and mixed at a speed of 27-30 rpm. The mixture is then lifted and pressed at intervals of 30 s, 25 s, and 20 s. When the mixing time reaches 110-120 s, the rubber is discharged and sheeted. After cooling, the cut-resistant, low-heat-generating engineering tire tread rubber based on the composite reinforcement system is obtained.

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