High-performance ring seam allowance rubber for off-the-road tire

Abstract

The invention discloses high-performance bead rubber for an off-the-road tire, and relates to the technical field of bead rubber for tires. According to the technical scheme, the rubber composition comprises the following components in parts by weight: 100 parts of a rubber component, 70-85 parts of carbon black, 2-4 parts of a carbon black dispersing agent, 6-10 parts of a compound synthetic agent HY-A22, 4-6 parts of environment-friendly oil, 2-4 parts of an anti-aging agent, 0.5-1 part of microcrystalline wax, 4-6 parts of zinc oxide, 2-3 parts of stearic acid, 1-2.5 parts of sulfur, 1-2 parts of N-methyl furfuryl amine and 0.8-1.5 parts of an accelerant. The N-methyl furfuryl amine and the compound synthetic agent HY-A22 are introduced, and the synergistic effect of the N-methyl furfuryl amine and the compound synthetic agent HY-A22 is utilized, so that the ageing resistance and the dynamic deflection resistance of the seam allowance glue are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of bead filler rubber for tires, and particularly to a high-performance bead filler rubber for construction machinery tires. Background Art

[0002] As a key part where the tire is in close contact with the rim, the bead filler rubber is of great importance. It is constantly subjected to complex dynamic flexural stresses, undergoes aging tests in high-temperature environments, and also faces continuous mechanical wear. The quality of its performance directly determines the sealing performance and durability of the tire, and thus affects the overall service life and safety of the tire.

[0003] In traditional bead filler rubber formulations, in order to pursue higher rigidity, a design concept of high-filled carbon black is often adopted. However, although this approach improves rigidity to a certain extent, it brings many problems that cannot be ignored:

[0004] First of all, the insufficient dynamic flexural resistance becomes a prominent shortcoming. The high-filled carbon black system significantly reduces the flexibility of the rubber compound. During the running of the tire, the bead part needs to continuously undergo flexural deformation. This repeated deformation is a severe challenge for the rubber compound with insufficient flexibility, easily leading to the generation and expansion of cracks, and thus affecting the sealing performance and service life of the tire.

[0005] Secondly, poor aging resistance is also a major pain point of traditional bead filler rubber. Due to the friction between the bead part and the rim, a large amount of heat is generated, accelerating the oxidation process of the rubber. In the high-filled carbon black system, the rubber compound is more easily affected by high temperatures, resulting in hardening, embrittlement, and even adhesion failure, seriously threatening the safe use of the tire.

[0006] To solve these problems, some attempts have been made in the prior art. For example, by adding plasticizers to improve the processing performance of the rubber compound, making it easier to extrude and form. However, this method often comes at the cost of sacrificing mechanical properties, resulting in a decrease in the strength and elasticity of the bead filler rubber, and unable to meet the actual use requirements of the tire. Another approach is to use high-cost special rubbers to improve the temperature resistance of the bead filler rubber, enabling it to better resist the influence of high-temperature aging. However, this method faces the problem of high cost, and it is difficult to achieve a balance between performance and cost, and it is difficult to be widely applied on a large scale.

[0007] Therefore, it is urgent to develop a new bead filler rubber formulation. This formulation needs to take into account excellent dynamic flexural resistance, outstanding aging resistance, and excellent mechanical properties on the premise of meeting good processing performance, achieving a comprehensive improvement in comprehensive performance, thereby effectively extending the service life of the tire, improving the safety and reliability of the tire, and providing new impetus for the development of the tire industry. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a high-performance bead filler for construction machinery tires. By introducing N-methylfurfurylamine and compound complexing agent HY-A22 and utilizing their synergistic effects, the aging resistance and dynamic flexing resistance of the bead filler are significantly improved, achieving a breakthrough improvement in comprehensive performance.

[0009] The technical solution of the present invention is as follows:

[0010] A high-performance bead filler for construction machinery tires, comprising the following components in parts by weight: 100 parts of rubber component, 70 - 85 parts of carbon black, 2 - 4 parts of carbon black dispersant, 6 - 10 parts of compound complexing agent HY-A22, 4 - 6 parts of environmental protection oil, 2 - 4 parts of antioxidant, 0.5 - 1 part of microcrystalline wax, 4 - 6 parts of zinc oxide, 2 - 3 parts of stearic acid, 1 - 2.5 parts of sulfur, 1 - 2 parts of N-methylfurfurylamine, and 0.8 - 1.5 parts of accelerator.

[0011] Among them, N-methylfurfurylamine is a nitrogen-containing heterocyclic compound. In addition to optimizing the cross-linking network structure as an accelerator and improving the aging resistance, the strong polar groups contained in its molecular structure can effectively adsorb free radicals in the rubber molecular chain and inhibit the high-temperature oxidation reaction. HY-A22 (Fujian Hongyuan High Polymer Materials Co., Ltd.) is a multifunctional compound additive that optimizes the filler dispersion, enhances the mechanical properties, and delays the material aging through physical dispersion and chemical activation, thereby improving the comprehensive performance of the final product.

[0012] Preferably, the rubber component is natural rubber NR and cis-butadiene rubber BR, wherein the natural rubber NR is 30 - 55 parts and the cis-butadiene rubber BR is 45 - 70 parts.

[0013] Preferably, the carbon black is N375 carbon black or a combination thereof with N220 carbon black.

[0014] Preferably, the carbon black dispersant is FNS-78T carbon black dispersant or homogenizer 40MSF.

[0015] Preferably, the environmental protection oil is naphthenic oil or tall oil.

[0016] Preferably, the antioxidant is p-phenylenediamine antioxidant 3100 and ketone-amine antioxidant RD.

[0017] Preferably, the accelerator is sulfenamide accelerator NS.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention enhances the aging resistance and dynamic flexural resistance of the bead gum by introducing N-methylfurfurylamine and the compounding agent HY-A22 and utilizing their synergistic effect. The nitrogen-containing heterocyclic structure of N-methylfurfurylamine can efficiently capture free radicals, while HY-A22 promotes the uniform distribution of fillers through its dispersion system and constructs a three-dimensional reinforcement network. The two work together to optimize the arrangement of rubber molecular chains and interfacial bonding. This combination not only greatly improves the tensile strength and wear resistance of the bead gum, extends the dynamic flexural life, but also significantly enhances the thermal-oxidative aging performance through a dual antioxidant mechanism (free radical capture + antioxidant protection), ultimately achieving a comprehensive breakthrough in the mechanical properties and durability of the bead gum.

[0020] 2. The present invention adjusts the conventional bead gum formula, increases the amount of cis-butadiene rubber, adjusts the carbon black structure, and uses the more wear-resistant N220 carbon black to partially replace the conventional N375 carbon black, which has a positive impact on the wear resistance and flexural performance of the bead gum. Specific Embodiments

[0021] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention.

[0022] Examples 1-3 and Comparative Examples 1-3

[0023] The formulas of the bead gums of the wheel rims of construction machinery tires in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1:

[0024] Table 1 Formulas of the bead gums of the wheel rims of construction machinery tires in Examples 1-3 and Comparative Examples 1-3

[0025]

[0026] The preparation methods of the bead gums of the wheel rims of construction machinery tires in Examples 1-3 and Comparative Examples 1-3 include the following steps:

[0027] S1 First-stage mixing

[0028] Put 20# standard rubber, BR9000, HY-A22, zinc oxide, antioxidant RD, antioxidant 3100, and microcrystalline wax into the internal mixer, mix for 30 s at a speed of 41 rpm, then put 50 parts of carbon black (preferably add N220) and 2 / 3 of the carbon black dispersant 40MSF into the internal mixer and mix for 40 s, then add naphthenic oil, and perform lifting and pressing of the rubber mass every 35 s. When the temperature of the rubber compound reaches 155 °C, discharge the rubber and take off the sheet, and place it at room temperature for 4 h to obtain the cooled first-stage masterbatch, and then perform second-stage mixing on it;

[0029] S2 Second-stage mixing

[0030] Put a section of masterbatch obtained in step S1, the remaining carbon black N375, the remaining carbon black dispersant 40MSF, and stearic acid into an internal mixer simultaneously, and conduct mixing at a rotational speed of 36 rpm. Perform lifting and pressing of the material every 35 s. When the temperature of the rubber compound reaches 150 °C, discharge the rubber and cut it into sheets. Place it at room temperature for 4 h to obtain the cooled second-stage masterbatch, and then conduct final mixing on it.

[0031] S3 Final mixing

[0032] Put the second-stage masterbatch obtained in step S2, sulfur, N-methylfurfurylamine, and accelerator NS into an internal mixer, and conduct mixing at a rotational speed of 28 rpm. Perform lifting and pressing of the material at intervals of 30 s, 30 s, and 25 s in sequence. When the temperature of the rubber compound reaches 105 °C, discharge the rubber and cut it into sheets. After placing it for cooling, the bead filler rubber for construction machinery tires is obtained.

[0033] Carry out high-temperature vulcanization on the bead filler rubbers for construction machinery tires prepared in Examples 1-3 and Comparative Examples 1-3 to prepare test samples, and then conduct performance tests on them. The test results are shown in Table 2:

[0034] Table 2 Performance test results of the vulcanized samples of the bead filler rubbers for construction machinery tires in Examples 1-3 and Comparative Examples 1-3

[0035] Test Items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Shore Hardness A / degree 73 71 69 72 74 70 Tensile Strength / MPa 21.8 23.5 19.8 19.5 20 20.2 Elongation at Break / % 420 420 450 410 440 390 Tensile Product 9156 9870 8910 7995 8800 7878 10% Modulus / MPa 1.5 1.6 1.1 1.2 1 1.5 100% Modulus / MPa 3 3.3 2.6 2.8 2.6 3.1 Compression Set / % 24 21 23 30 28 25 <![CDATA[Wear / cm 3 / 1.61 km]]> 0.31 0.34 0.3 0.35 0.34 0.33 Rebound / % 53 56 51 52 48 55 Aging Coefficient / % 82 80 80 74 76 78 Growth of Flex Cracks / kc 40 39 40 35 37 38

[0036] Vulcanization conditions for the test samples: 147 °C × 60 min; Aging test conditions: 100 °C × 48 h hot air;

[0037] Aging coefficient = Tensile product after aging / Tensile product before aging.

[0038] Comparing Example 1 with Comparative Example 1, it can be found that for the rubber compound with the simultaneous addition of HY-A22 and N-methylfurfurylamine, the hardness and elongation at break are basically unchanged, the tensile strength is increased from 19.5 MPa to 21.8 MPa, and the tensile product is increased by about 11.8%; the abrasion resistance is reduced from 0.35 cm 3 to 0.31 cm 3 , and the abrasion is reduced by about 11.4%; the compression set of the rubber compound is reduced from 30% to 24%, the crack resistance under flexure is increased by about 14%, and the resilience is comparable. This is mainly due to the fact that the dispersant in HY-A22 promotes the uniform dispersion of the filler, enhances the rubber-filler interface bonding, and at the same time N-methylfurfurylamine improves the molecular chain flexibility and reduces the frictional loss. These two materials synergistically optimize the filler network structure and improve the performance of the rubber compound. Comparing Example 1 with Comparative Examples 2-3, it can be found that the rubber compound with the simultaneous addition of HY-A22 and N-methylfurfurylamine has more excellent comprehensive performance compared with the rubber compounds with the addition of only one of these materials.

[0039] HY-A22 is a multifunctional composite additive, and its core components include dispersants (PEG, fatty acid salts), activators (zinc oxide, stearic acid derivatives), and anti-aging agents (SP, MB). These components work synergistically to significantly promote filler dispersion, reduce mixing viscosity, improve the fluidity and mechanical properties of the rubber compound, and delay material aging. N-methylfurfurylamine is a nitrogen-containing heterocyclic compound, and the strong polar groups in its molecular structure can effectively adsorb free radicals in the rubber molecular chain and inhibit high-temperature oxidation reactions. As an efficient accelerator, N-methylfurfurylamine can also activate the vulcanization system, accelerate the formation of the sulfur crosslinking network, and optimize the crosslink density distribution of the vulcanizate; this effect synergizes with the activator (zinc oxide / stearic acid derivatives) in HY-A22 to further enhance the vulcanization efficiency and optimize the crosslinking network, synchronously enhancing the dynamic mechanical properties and heat resistance of the composite material. When the two materials are used together, the rigid filler network constructed by HY-A22 and the molecular chain flexibility adjustment provided by N-methylfurfurylamine complement each other, avoiding the brittleness problem of the high-fill system and ensuring excellent dynamic performance; the free radical capture effect of N-methylfurfurylamine and the anti-aging agent of HY-A22 form a gradient protection system, significantly enhancing the aging resistance performance; in terms of processing performance, the viscosity reduction effect of N-methylfurfurylamine and the anti-agglomeration characteristics of HY-A22 promote each other. After multiple rounds of large-scale production verification in the factory workshop, the surface of the rubber compound is smooth without pitting, and the extrusion difficulty of the rubber compound is slightly reduced compared with before, ensuring the processing stability of the rubber compound and the reproducibility of the final performance. By combining with the adjustment of the main formula of the bead filler, increasing the amount of cis-butadiene rubber, and using some more wear-resistant N220 carbon black, through the synergistic effects in multiple aspects, the rubber compound is significantly improved in terms of mechanical properties, wear resistance, dynamic performance, and durability, greatly improving the performance of the bead filler of the tire bead.

Claims

1. High-performance bead filler for construction machinery tires, characterized in that, Comprising the following components in parts by weight: 100 parts of rubber component, 70 - 85 parts of carbon black, 2 - 4 parts of carbon black dispersant, 6 - 10 parts of compound comprehensive agent HY - A22, 4 - 6 parts of environmental protection oil, 2 - 4 parts of anti - aging agent, 0.5 - 1 part of microcrystalline wax, 4 - 6 parts of zinc oxide, 2 - 3 parts of stearic acid, 1 - 2.5 parts of sulfur, 1 - 2 parts of N - methylfurfurylamine, 0.8 - 1.5 parts of accelerator.

2. The high-performance bead filler for construction machinery tires according to claim 1, wherein, The rubber component is natural rubber NR and cis - 1,4 - polybutadiene rubber BR.

3. The high-performance bead filler rubber for construction machinery tires as described in claim 1, wherein The carbon black is N375 carbon black or a combination of it and N220 carbon black.

4. The high-performance bead filler for construction machinery tires according to claim 1, wherein, The carbon black dispersant is FNS - 78T carbon black dispersant or homogenizer 40MSF.

5. The high-performance bead apex rubber for construction machinery tires according to claim 1, characterized in that, The environmental protection oil is naphthenic oil or tall oil.

6. The high-performance bead filler for construction machinery tires according to claim 1, characterized in that The anti - aging agent is p - phenylenediamine anti - aging agent 3100 and keto - amine anti - aging agent RD.

7. The high-performance bead filler for construction machinery tires according to claim 1, wherein, The accelerator is sulfenamide accelerator NS.

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