Tire inner liner rubber composition with high renewable material content as well as preparation method and application of tire inner liner rubber composition

Abstract

The invention discloses a tire inner liner rubber composition with high renewable material content. The tire inner liner rubber composition is prepared from the following raw materials in parts by weight: 10 to 50 parts of natural rubber, 30 to 80 parts of halogenated butyl rubber, 10 to 60 parts of butyl reclaimed rubber, 40 to 150 parts of filler, 1 to 50 parts of plasticizer, 0 to 50 parts of tackifying resin, 2 to 10 parts of active agent, 0.5 to 5 parts of vulcanizing agent and 0.5 to 3 parts of accelerant, wherein the sum of the weight parts of the natural rubber, the halogenated butyl rubber and the rubber hydrocarbon part of the butyl reclaimed rubber is 100; the weight part ratio of the butyl reclaimed rubber to the halogenated butyl rubber is greater than 0.20 and less than or equal to 0.91. Four sustainable materials including butyl reclaimed rubber, natural rubber, pyrolysis carbon black and bio-based oil are introduced, and meanwhile, the dosage proportion is limited, so that the proportion of the sustainable materials in the tire airtight layer is remarkably increased to 50% or above; and on the premise that the original physical properties of the rubber composition are not lost, the gas retention performance of the tire is improved, and the purposes of reducing the material cost, saving energy and reducing emission are achieved.

Description

Technical Field

[0001] This invention belongs to the field of semi-steel tire airtight layer rubber, specifically relating to a tire airtight layer rubber composition with high renewable material content, its preparation method, and its application. Background Technology

[0002] The sustainability and renewability of tires have become important issues in the automotive industry and environmental protection sector. As a key component of tubeless tires, the airtight layer is directly responsible for maintaining internal air pressure, and its performance directly affects the tire's safety, durability, and energy efficiency. The airtight layer must meet several stringent requirements: excellent airtightness to prevent gas leakage; good fatigue resistance to resist cracks caused by repeated deformation; and strong adhesion to the tire carcass and other components.

[0003] Currently, tire airtight layers widely employ a blend of natural rubber and halogenated butyl rubber. Halogenated butyl rubber, due to its dense molecular structure and low unsaturation, exhibits significantly superior airtightness, making it the primary choice for airtight layers. However, this system still has drawbacks: halogenated butyl rubber is expensive and has poor processing performance; increasing the proportion of natural rubber to improve economics leads to an increase in air permeability and a decrease in airtightness.

[0004] Regarding fillers, increasing the dosage can enhance airtightness, modulus, and hardness, but excessive dosage can easily lead to uneven dispersion and deterioration of dynamic fatigue performance. The addition of plasticizers helps improve processability, but excessive amounts can increase molecular chain mobility, thereby reducing airtightness. For sustainable materials applications, existing technologies mostly focus on replacing single fossil raw materials, making it difficult to systematically increase the overall proportion of renewable materials. For example, existing technologies propose using itaconic acid ester rubber to partially replace natural rubber and halogenated butyl rubber, but this still faces problems such as limited market supply and high preparation costs, making it difficult to achieve large-scale industrial application. Therefore, the industry urgently needs a formulation and preparation method that can significantly increase the renewable material content while also taking into account the key performance characteristics of the airtight layer. Summary of the Invention

[0005] The purpose of this invention is to provide a tire air-tight layer rubber composition with a high content of renewable materials, its preparation method, and its application. While maintaining other physical properties of the original rubber composition, it improves the tire's air-holding performance and introduces four sustainable materials—butyl reclaimed rubber, natural rubber, pyrolyzed carbon black, and bio-based oil—in optimal proportions. The proportion of sustainable materials in the tire air-tight layer is increased to over 50%, reducing the tire air-tight layer formulation's dependence on petroleum-based materials and increasing the product's renewable material content.

[0006] The first objective of this invention is to provide a tire airtight layer rubber composition with a high content of renewable materials, comprising the following raw materials in parts by weight: 10-50 parts of natural rubber, 30-80 parts of halogenated butyl rubber, 10-60 parts of butyl reclaimed rubber, 40-150 parts of filler, 1-50 parts of plasticizer, 0-50 parts of tackifying resin, 2-10 parts of activator, 0.5-5 parts of vulcanizing agent, and 0.5-3 parts of accelerator; wherein the sum of the weight parts of the hydrocarbon portion of the natural rubber, halogenated butyl rubber, and butyl reclaimed rubber is 100 parts; and the weight ratio of the butyl reclaimed rubber to the halogenated butyl rubber satisfies: 0.20 < butyl reclaimed rubber / halogenated butyl rubber ≤ 0.91.

[0007] The use of natural rubber and butyl reclaimed rubber increases the proportion of sustainable materials, and their price is lower than that of synthetic halogenated butyl rubber and bio-based rubber. Butyl reclaimed rubber and halogenated butyl rubber provide excellent airtightness, while natural rubber strengthens the adhesion between the airtight layer and other components. When the weight ratio is greater than 0.91, airtightness decreases, fatigue is reduced, fatigue cracks are more likely to occur, and airtightness function fails. The filler includes reinforcing carbon black and recycled carbon black; wherein the amount of reinforcing carbon black is 10 to 50 parts by weight and the amount of recycled carbon black is 20 to 60 parts by weight.

[0008] The weight ratio of recycled carbon black to reinforcing carbon black shall satisfy: 1.00 < recycled carbon black / reinforcing carbon black ≤ 5.0.

[0009] The addition of carbon black significantly improves the abrasion resistance, tensile strength, modulus, tear strength, and swelling resistance of vulcanizates. When the carbon black content is too high, the hardness of the compound decreases, heat generation increases, and the Ts / Eb ratio decreases; conversely, when the carbon black content is too low, the compound's hardness is too high, and tensile fatigue resistance decreases.

[0010] The plasticizer is bio-based oil V150, and the dosage is 1-20 parts.

[0011] The tackifying resin comprises at least one of C5 petroleum resin, C9 petroleum resin, α-methylstyrene resin, indene resin, phenolic resin, and terpene resin.

[0012] The activators include zinc oxide and stearic acid.

[0013] The vulcanizing agent includes at least one of ordinary sulfur, insoluble sulfur, sulfur-containing compounds, and peroxides.

[0014] The accelerator is at least one of dithiobenzothiazole, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N,N-dicyclohexyl-2-benzothiazole sulfenamide, diphenylguanidine, o-tolyldiguanidine, and di-o-tolylguanidine.

[0015] A second objective of this invention is a method for preparing the tire airtight layer rubber composition with high renewable material content, comprising the following steps: S1. First-stage masterbatch: Add natural rubber, halogenated butyl rubber, butyl reclaimed rubber, tackifying resin and filler to the internal mixer, mix for 60 seconds or until the material temperature reaches 110°C, add plasticizer and continue mixing for 30 seconds; then lift the top plug to float for 10 seconds, then press down the top plug to mix for 30 seconds; lift the top plug to float for 10 seconds again, and finally press down the top plug to mix for 90 seconds or until the material temperature reaches 130°C, then discharge the rubber to obtain the first-stage masterbatch. S2, Second-stage masterbatch: The first-stage masterbatch rubber is put back into the internal mixer, and an activator is added. The top plug is pressed down and the mixture is mixed for 30 seconds. Then the top plug is raised and floated for 10 seconds. The top plug is then pressed down and the mixture is mixed for 90 seconds or until the material temperature reaches 130°C and the rubber is discharged to obtain the second-stage masterbatch rubber. S3. Final mixing: The two-stage masterbatch is put back into the internal mixer, and vulcanizing agent and accelerator are added. The top plug is pressed down and the mixture is mixed for 30 seconds. Then the top plug is raised and floated for 10 seconds. The top plug is then pressed down and the mixture is mixed for 90 seconds or until the material temperature reaches 100°C before the rubber is discharged to obtain the final rubber compound.

[0016] A third object of the present invention is the use of the tire airtight layer rubber composition with high renewable material content in the manufacture of tire airtight layers, vulcanized bladders or inner tubes.

[0017] Compared with the prior art, the tire airtight layer rubber composition with high renewable material content and its preparation method provided by the present invention have the following beneficial effects: This invention introduces four sustainable materials—butyl reclaimed rubber, natural rubber, pyrolysis carbon black, and bio-based oil—while limiting their proportions, significantly increasing the proportion of sustainable materials in the tire's airtight layer to over 50%, effectively reducing dependence on petroleum-based materials. Furthermore, this invention can further improve the tire's air retention performance while maintaining the original physical properties of the rubber composition, simultaneously achieving the goals of reducing material costs, saving energy, and reducing emissions, thus comprehensively enhancing the product's environmental attributes and economic efficiency. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0019] The raw materials used in the embodiments of the present invention are as follows: *1. Halogenated butyl rubber: LVCIIR chlorinated butyl rubber, commercially available.

[0020] *2. Butyl reclaimed rubber: Fujian Zhonghong New Material Technology Co., Ltd., commercially available. The rubber hydrocarbon content is 50wt%.

[0021] *3. Reinforcing Carbon Black: N660, manufactured by Jiangxi Black Cat Carbon Black Co., Ltd., commercially available.

[0022] *4. Recycled carbon black: LN607, Shandong Kaiyuan Runfeng Environmental Protection Technology Co., Ltd., commercially available.

[0023] *5. Bio-based oil: TUDASOL 150, manufactured by Hansheng Petrochemical (Ningbo) Co., Ltd., commercially available.

[0024] *6. Plasticizer: Environmentally friendly NAP oil, commercially available.

[0025] *7. Tackifying resin: C5 resin, commercially available.

[0026] *8. Vulcanizing agent: Ordinary sulfur S, commercially available.

[0027] *9. Accelerator: Accelerator DM, commercially available.

[0028] *10. Surfactants: Zinc oxide and stearic acid are both commercially available.

[0029] The present invention will be described in detail below with reference to specific embodiments.

[0030] The formulations of each embodiment and comparative example are shown in Table 1. The raw materials for each experiment were prepared according to the following process, wherein the internal mixer was a GK270 model from Yiyang Rubber & Plastics Machinery Group Co., Ltd.

[0031] Preparation process: S1, First stage masterbatch: Add natural rubber, halogenated butyl rubber, butyl reclaimed rubber, tackifying resin and filler to the internal mixer, mix for 60 seconds or until the material temperature reaches 110°C, add plasticizer and continue mixing for 30 seconds; then lift the top plug to float for 10 seconds, then press down the top plug to mix for 30 seconds; lift the top plug to float for 10 seconds again, and finally press down the top plug to mix for 90 seconds or until the material temperature reaches 130°C, then discharge the rubber to obtain the first stage masterbatch; S2, Second-stage masterbatch: The first-stage masterbatch rubber is put back into the internal mixer, and an activator is added. The top plug is pressed down and the mixture is mixed for 30 seconds. Then the top plug is raised and floated for 10 seconds. The top plug is then pressed down and the mixture is mixed for 90 seconds or until the material temperature reaches 130°C and the rubber is discharged to obtain the second-stage masterbatch rubber. S3. Final mixing: The two-stage masterbatch is put back into the internal mixer, and vulcanizing agent and accelerator are added. The top plug is pressed down and the mixture is mixed for 30 seconds. Then the top plug is raised and floated for 10 seconds. The top plug is then pressed down and the mixture is mixed for 90 seconds or until the material temperature reaches 100°C before the rubber is discharged to obtain the final rubber compound.

[0032] Table 1

[0033] Performance testing: The final compound was vulcanized using a flat vulcanizing machine to obtain vulcanized rubber (vulcanization conditions: 160℃*13min). The performance of the vulcanized rubber was tested, and the test results are shown in Table 2.

[0034] The testing method standard is as follows: Shore hardness: GB / T531.1-2008 Tensile stress-strain: GB / T528-2009 DMA temperature scan: Test temperature -30℃~100℃, dynamic 0.3%, static 3%. Tensile fatigue: ASTM D4482, 100% strain Air tightness: GB / T1038 Table 2

[0035] Shore hardness: The value obtained by measuring a standard sample using a Shore hardness tester, which characterizes the rubber's ability to resist deformation under external stress; Tensile strength: The strength of a standard tensile specimen at which it breaks under tension, and together with elongation at break, it characterizes the rubber's resistance to damage. Elongation at break: The elongation at which a standard tensile specimen breaks under tension, which, together with tensile strength, characterizes the rubber's resistance to breakage; DMA 60℃ Tanδ: The hysteresis loss Tanδ of rubber at 60℃. According to the room temperature equivalence principle of viscoelastic materials, it can be used to characterize the rolling resistance of rubber, that is, the rate of heat generation. The larger the Tanδ at 60℃, the greater the heat generation. Tensile fatigue: The number of fatigue failures of a rubber compound under cyclic strain conditions; the higher the value, the better the resistance of the rubber compound to fatigue failure. Air tightness: Gas permeability coefficient per unit volume of rubber compound. The larger the coefficient, the greater the amount of gas that can pass through per unit volume of rubber compound, and the worse the air tightness.

[0036] Combining Table 1 and Table 2, we can see that: 1. Comparative Example 1 is a typical airtight layer formulation that does not use butyl recycled rubber, bio-based oil and recycled carbon black. Compared with Comparative Example 1, the performance of the example is comparable, the proportion of sustainable materials is increased and the cost is reduced. 2. Comparative Example 2 has a low proportion of sustainable materials, high cost, large amount of reinforcing carbon black, high hardness, and reduced fatigue. 3. In the comparative example, excessive use of 3-butyl reclaimed rubber reduced its resistance to fatigue damage and increased heat generation. 4. In Comparative Example 4, excessive use of recycled carbon black resulted in decreased hardness, reduced resistance to fatigue damage, and increased heat generation.

[0037] It is evident that the use of sustainable materials requires addition in specific proportions. If the proportions are inappropriate, the performance of the rubber compound will decrease excessively. The ultimate goal of this invention is to increase the amount of sustainable materials as much as possible while maintaining comparable rubber compound performance and taking into account manufacturing costs.

[0038] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A tire airtight layer rubber composition with high renewable material content, characterized in that, Including the following parts by weight of raw materials: 10-50 parts natural rubber 30-80 parts of halogenated butyl rubber 10-60 parts of butyl reclaimed rubber 40-150 parts of filler Plasticizer 1-50 parts, 0-50 parts of tackifying resin Surfactant 2-10 parts, Vulcanizing agent 0.5~5 parts, Accelerator 0.5-3 parts; The sum of the weight parts of the rubber hydrocarbon portion of the natural rubber, halogenated butyl rubber and butyl reclaimed rubber is 100 parts. The weight ratio of butyl reclaimed rubber to halogenated butyl rubber satisfies the following condition: 0.20 < butyl reclaimed rubber / halogenated butyl rubber ≤ 0.

91.

2. The tire airtight layer rubber composition with high renewable material content according to claim 1, characterized in that, The filler includes reinforcing carbon black and recycled carbon black; wherein the amount of reinforcing carbon black is 10 to 50 parts by weight and the amount of recycled carbon black is 20 to 60 parts by weight.

3. The tire airtight layer rubber composition with high renewable material content according to claim 2, characterized in that, The weight ratio of recycled carbon black to reinforcing carbon black shall satisfy: 1.00 < recycled carbon black / reinforcing carbon black ≤ 5.

0.

4. The tire airtight layer rubber composition with high renewable material content according to claim 1, characterized in that, The plasticizer is bio-based oil V150, and the dosage is 1-20 parts.

5. The tire airtight layer rubber composition with high renewable material content according to claim 1, characterized in that, The tackifying resin comprises at least one of C5 petroleum resin, C9 petroleum resin, α-methylstyrene resin, indene resin, phenolic resin, and terpene resin.

6. The tire airtight layer rubber composition with high renewable material content according to claim 1, characterized in that, The activators include zinc oxide and stearic acid.

7. The tire airtight layer rubber composition with high renewable material content according to claim 1, characterized in that, The vulcanizing agent includes at least one of ordinary sulfur, insoluble sulfur, sulfur-containing compounds, and peroxides.

8. The tire airtight layer rubber composition with high renewable material content according to claim 1, characterized in that, The accelerator is at least one of dithiobenzothiazole, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N,N-dicyclohexyl-2-benzothiazole sulfenamide, diphenylguanidine, o-tolyldiguanidine, and di-o-tolylguanidine.

9. A method for preparing a tire airtight layer rubber composition with high renewable material content as described in claims 1-8, characterized in that, Includes the following steps: S1. First-stage masterbatch: Add natural rubber, halogenated butyl rubber, butyl reclaimed rubber, tackifying resin and filler to the internal mixer, mix for 60 seconds or until the material temperature reaches 110°C, add plasticizer and continue mixing for 30 seconds; then lift the top plug to float for 10 seconds, then press down the top plug to mix for 30 seconds; lift the top plug to float for 10 seconds again, and finally press down the top plug to mix for 90 seconds or until the material temperature reaches 130°C, then discharge the rubber to obtain the first-stage masterbatch. S2, Second-stage masterbatch: The first-stage masterbatch rubber is put back into the internal mixer, and an activator is added. The top plug is pressed down and the mixture is mixed for 30 seconds. Then the top plug is raised and floated for 10 seconds. The top plug is then pressed down and the mixture is mixed for 90 seconds or until the material temperature reaches 130°C and the rubber is discharged to obtain the second-stage masterbatch rubber. S3. Final mixing: The two-stage masterbatch is put back into the internal mixer, and vulcanizing agent and accelerator are added. The top plug is pressed down and the mixture is mixed for 30 seconds. Then the top plug is raised and floated for 10 seconds. The top plug is then pressed down and the mixture is mixed for 90 seconds or until the material temperature reaches 100°C before the rubber is discharged to obtain the final rubber compound.

10. The use of a tire airtight layer rubber composition with a high renewable material content as described in any one of claims 1-8 in the manufacture of tire airtight layers, vulcanized bladders, or inner tubes.

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