An airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution, its preparation method, and a tubeless self-sealing tire.

Abstract

This application belongs to the field of rubber compound technology, and particularly relates to an airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution, a preparation method thereof, and a tubeless self-sealing tire. The airtight rubber compound provided by this application uses pyrolysis carbon black and carbon black with a wide particle size distribution, which is beneficial for wetting and mixing into the raw rubber, improving dispersibility, and improving the airtightness and physical and mechanical properties of the rubber compound used in the tire airtight layer. At the same time, the use of pyrolysis carbon black obtained by recycling waste tires also reduces the preparation cost, thereby solving the technical problem that the physical and mechanical properties and airtightness of the rubber compound formulation used in the tire airtight layer in the prior art need to be improved.

Description

Technical Field

[0001] This application belongs to the field of rubber compound technology, and particularly relates to an airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution, its preparation method, and a tubeless self-sealing tire. Background Technology

[0002] Unlike conventional tires, tubeless self-sealing tires rely on the airtight layers of the tire inner wall and bead to ensure good airtightness between the tire and the rim. As an important component, the tire airtight layer has low gas leakage and can maintain tire pressure and air retention during vehicle operation. At the same time, it must have good flexural fatigue performance and ozone resistance. Appropriate tire pressure is the guarantee to ensure that the tire performance can reach its maximum effect.

[0003] Currently, the rubber compound formulations used in tire airtight layers mainly consist of natural rubber and / or halogenated butyl rubber and fully halogenated butyl rubber, with the addition of reinforcing fillers such as carbon black or calcium carbonate, as well as other additives. This results in high formulation costs and high processing performance, but the physical and mechanical properties and airtightness need improvement. Recycling waste tires is beneficial for energy regeneration, improving material utilization, and reducing environmental pollution. Currently, recycled waste tires undergo physical cleaning, crushing, pulverizing, and pyrolysis to produce materials such as pyrolyzed carbon black, pyrolyzed oil, and tire cord wire fragments. These materials are then processed through screening, magnetic separation, grading, and air separation to ultimately produce pyrolyzed carbon black. Pyrolyzed carbon black is characterized by its low price, environmental friendliness, low secondary structure, complex particle size distribution, and easy dispersion. It also retains reinforcing additives such as silica and calcium carbonate, making it a potential substitute for carbon black reinforcing agents in tire airtight layer formulations. Summary of the Invention

[0004] In view of this, this application provides an airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution, a preparation method thereof, and a tubeless self-sealing tire, to solve the technical problem that the physical and mechanical properties and airtightness of the rubber compound formulation used in the airtight layer of tires in the prior art need to be improved.

[0005] The first aspect of this application provides an airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution, including raw rubber, reinforcing filler, activator, vulcanizing agent, accelerator and processing aid;

[0006] The reinforcing filler includes composite carbon black and light calcium carbonate;

[0007] The nitrogen adsorption specific surface area of ​​the composite carbon black is 30-100 m². 2 / g, iodine uptake value is 30-140g / kg;

[0008] The composite carbon black includes carbon black and pyrolysis carbon black.

[0009] Preferably, the raw rubber includes natural rubber and brominated butyl rubber.

[0010] Preferably, the raw rubber further includes butyl reclaimed rubber.

[0011] Preferably, the airtight rubber compound comprises, by weight, 90-150 parts raw rubber, 10-100 parts reinforcing filler, 1-4 parts activator, 2-6 parts vulcanizing agent, 0.5-2 parts accelerator and 15-25 parts processing aid.

[0012] Preferably, the airtight rubber compound comprises 100-140 parts of raw rubber, 10-100 parts of reinforcing filler, 1-4 parts of activator, 2-6 parts of vulcanizing agent, 0.5-2 parts of accelerator and 15-25 parts of processing aid.

[0013] Preferably, the dry weight ratio of the natural rubber to the brominated butyl rubber is 10-40:90-60.

[0014] Preferably, the mass ratio of medium carbon black to pyrolysis carbon black in the composite carbon black is 0-70:70-0.

[0015] Preferably, the activator is stearic acid;

[0016] The vulcanizing agent is selected from one or more of sulfur powder, insoluble sulfur, and zinc oxide;

[0017] The accelerator is accelerator DM;

[0018] The processing aids include homogenizers, resins, and processing oils;

[0019] The homogenizer is 40 MSF;

[0020] The resin is selected from one or more of the following: octylphenol resin, tert-butylphenol tackifying resin, fatty acid resin C5, hydrocarbon resin C9, and mixtures of resin and asphalt.

[0021] The operating oil is an aromatic operating oil and / or an environmentally friendly operating oil.

[0022] Preferably, the airtight rubber compound, by weight, comprises 31 parts by weight of natural rubber, 69 parts by weight of brominated butyl rubber, 27 parts by weight of butyl reclaimed rubber, 25 parts by weight of light calcium carbonate, 40 parts by weight of granulated pyrolysis carbon black, 27 parts by weight of N660 carbon black, 2 parts by weight of stearic acid, 4 parts by weight of octylphenol resin, 7 parts by weight of 40MSF homogenizer, 3 parts by weight of fatty acid resin, 1.5 parts by weight of processing oil, 1.5 parts by weight of accelerator DM, 3 parts by weight of zinc oxide, and 0.6 parts by weight of insoluble sulfur.

[0023] The second aspect of this application provides a method for preparing an airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution, for preparing the aforementioned airtight rubber compound, the preparation method comprising the following steps:

[0024] Step S1: Raw rubber, reinforcing filler, activator and processing aid are sequentially subjected to a first stage mastering process and a second stage mastering process to obtain a two-stage mastering rubber;

[0025] Step S2: The two-stage masterbatch, vulcanizing machine and accelerator are subjected to final mixing, and the rubber is discharged to obtain airtight layer rubber compound.

[0026] A third aspect of this application provides a tubeless self-sealing tire, comprising a tire carcass, a cord fabric, an outer tread, and the aforementioned airtight rubber compound;

[0027] The airtight rubber compound adheres to the inner layer of the tire to form the tire's airtight layer.

[0028] In summary, this application provides an airtight rubber compound containing pyrolytic carbon black with a wide particle size distribution, a preparation method thereof, and a tubeless self-sealing tire. The airtight rubber compound includes raw rubber, reinforcing fillers, activators, vulcanizing agents, accelerators, and processing aids. The reinforcing fillers include composite carbon black and light calcium carbonate. Compared with using only carbon black, using composite carbon black, which includes both carbon black and pyrolytic carbon black, can improve the density and physical and mechanical properties of the rubber compound at the same addition amount. The nitrogen adsorption specific surface area of ​​the composite carbon black is 30–100 m². 2 The iodine adsorption value is 30–140 g / kg. The iodine adsorption value is directly proportional to the nitrogen adsorption specific surface area, while the nitrogen adsorption specific surface area is inversely proportional to the particle size. The nitrogen adsorption specific surface area is 30–100 m². 2 The iodine absorption value of 30–140 g / kg indicates that this application provides a composite carbon black with a wide particle size distribution. This wide particle size distribution facilitates wetting and mixing into raw rubber, improves dispersibility, and further enhances the airtightness of the rubber compound used in tire airtight layers. Simultaneously, since the composite carbon black utilizes pyrolysis carbon black obtained from the recycling of waste tires, the amount of conventional carbon black used is reduced, thereby lowering preparation costs. This application provides a low-cost, high-airtightness rubber compound, thus solving the technical problem that the physical and mechanical properties and airtightness of rubber compound formulations used in tire airtight layers in the prior art need to be improved. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the process for preparing the airtight adhesive material provided in Embodiment 2 of this application. Detailed Implementation

[0031] This application provides an airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution, a preparation method thereof, and a tubeless self-sealing tire, which solves the technical problem that the physical and mechanical properties and airtightness of the rubber compound formulations used in the airtight layer of tires in the prior art need to be improved.

[0032] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Example 1

[0034] Given that the current tire airtight layer rubber compound formulations mainly consist of natural rubber and / or halogenated butyl rubber, fully halogenated butyl rubber, and reinforcing fillers and additives such as carbon black or calcium carbonate, the production cost is high and the performance is low; Example 1 of this application provides an airtight rubber compound containing pyrolytic carbon black with a wide particle size distribution; the airtight rubber compound consists of raw rubber, reinforcing fillers, activators, vulcanizing agents, accelerators, and processing aids, wherein the reinforcing fillers include composite and light calcium carbonate, the composite carbon black includes carbon black and pyrolytic carbon black, the recovered pyrolytic carbon black contains a large number of large-particle-size particles, and the composite carbon black obtained by compounding with carbon black has a wide particle size distribution, reflected in the nitrogen adsorption specific surface area of ​​the composite carbon black being 30-100 m². 2 With an iodine absorption value of 30–140 g / kg and a particle size distribution, the composite carbon black is beneficial for wetting and mixing into raw rubber, improving dispersibility, enhancing the flexibility and other physical and mechanical properties of the rubber compound, and improving the airtightness of the rubber compound used in the tire airtight layer. At the same time, the use of recycled pyrolysis to replace part of the carbon black helps to reduce the preparation cost, thereby solving the technical problem that the physical and mechanical properties and airtightness of the rubber compound formulation used in the tire airtight layer in the existing technology need to be improved.

[0035] For the raw rubber component in airtight rubber compounds, this application prefers natural rubber and brominated butyl rubber. The raw rubber system composed of natural rubber and brominated butyl rubber has good compatibility, which is conducive to the dispersion of reinforcing fillers such as composite carbon black in the raw rubber and improves the performance of the rubber compound. At the same time, brominated butyl rubber can also be made from butyl recycled rubber, thereby further reducing the production cost of the rubber compound.

[0036] Regarding the ratio of carbon black to pyrolysis carbon black in composite carbon black, this application preferably uses 0-70 parts by mass of carbon black and 0-70 parts by mass of pyrolysis carbon black, and more preferably 40 parts by mass of pyrolysis carbon black and 27 parts by mass of carbon black.

[0037] Regarding the ratio of natural rubber to brominated butyl rubber in the airtight rubber compound, this application preferably includes 10 to 40 parts by weight of natural rubber and 60 to 90 parts by weight of brominated butyl rubber.

[0038] For the activator, vulcanizing agent, accelerator, and processing aid in the airtight rubber compound, the preferred activator in this application is stearic acid; the vulcanizing agent is selected from one or more of sulfur powder, insoluble sulfur, and zinc oxide; the accelerator is accelerator DM; the processing aid includes homogenizer, resin, and processing oil; the homogenizer is 40MSF; the resin is selected from one or more of octylphenol resin, tert-butylphenol tackifying resin, fatty acid resin C5, hydrocarbon resin C9, and mixtures of resin and asphalt; the processing oil is aromatic processing oil and / or environmentally friendly processing oil.

[0039] This application also provides an excellent formulation of an airtight rubber compound. The airtight rubber compound, calculated by weight, comprises 31 parts by weight of natural rubber, 69 parts by weight of brominated butyl rubber, 27 parts by weight of butyl reclaimed rubber, 25 parts by weight of light calcium carbonate, 40 parts by weight of granulated pyrolysis carbon black, 27 parts by weight of N660 carbon black, 2 parts by weight of stearic acid, 4 parts by weight of octylphenol resin, 7 parts by weight of 40MSF homogenizer, 3 parts by weight of fatty acid resin, 1.5 parts by weight of processing oil, 1.5 parts by weight of accelerator DM, 3 parts by weight of zinc oxide, and 0.6 parts by weight of insoluble sulfur. Compared with conventional rubber compounds, the airtightness of this formulation is about 10% higher, and its physical and mechanical properties, such as tensile stress, tensile strength, and spherical rebound, are about 10% better than those of conventional rubber compounds.

[0040] Example 2

[0041] Example 2 of this application provides a method for preparing the airtight rubber compound containing pyrolysis carbon black with a wide particle size distribution as described in Example 1. The preparation method is a two-stage mixing method using an internal mixer to produce rubber sheets. The preparation method includes a raw material preparation step, a first stage and a second stage master mixing step, and a final mixing step.

[0042] The raw material preparation steps include: weighing 31 parts by weight of natural rubber, 69 parts of brominated butyl rubber, 27 parts of butyl reclaimed rubber, 25 parts of light calcium carbonate, and 67 parts of composite carbon black. The nitrogen adsorption specific surface area of ​​the composite carbon black is 30-100 m². 2 / g, iodine absorption value 30~140g / kg; composite carbon black includes 40 parts of pyrolysis carbon black, which is a mixture of granulated pyrolysis carbon black and powdered pyrolysis carbon black, 27 parts of N660 carbon black, 2 parts of stearic acid, 4 parts of octylphenol resin, 7 parts of 40MSF homogenizer, 3 parts of fatty acid resin, 1.5 parts of processing oil, 1.5 parts of accelerator DM, 3 parts of zinc oxide, and 0.6 parts of insoluble sulfur.

[0043] The first and second mastering steps include: adding 31 parts of natural rubber, 69 parts of brominated butyl rubber, 27 parts of butyl reclaimed rubber, 25 parts of light calcium carbonate, 40 parts of pyrolysis carbon black, 27 parts of N660 carbon black, 2 parts of stearic acid, 4 parts of octylphenol resin, 7 parts of 40MSF homogenizer, 3 parts of fatty acid resin, and 1.5 parts of processing oil into an internal mixer for mixing to obtain a first-stage masterbatch. The first-stage masterbatch is then added to the internal mixer for a second-stage mastering process to obtain a second-stage masterbatch. The preferred discharge temperature of the first-stage masterbatch is 130℃, and the mixing time is ≥120s. The preferred discharge temperature of the second-stage masterbatch is 128℃.

[0044] The final mixing step includes: adding 1.5 parts of accelerator DM, 3 parts of zinc oxide, and 0.6 parts of insoluble sulfur to the masterbatch and then performing final mixing to obtain the final rubber compound. The discharge temperature of the final rubber compound is preferably 108°C to obtain the airtight layer rubber compound.

[0045] Example 3

[0046] Example 3 of this application provides a method for preparing a rubber compound. As a comparative example of the airtight rubber compound described in Example 2, the preparation method is a two-stage mixing method using an internal mixer to produce rubber sheets. The preparation method includes a raw material preparation step, a first-stage and a second-stage master mixing step, and a final mixing step.

[0047] The raw material preparation steps include: weighing 31 parts of natural rubber, 69 parts of brominated butyl rubber, 27 parts of butyl reclaimed rubber, 25 parts of light calcium carbonate, 40 parts of granulated pyrolysis carbon black, 27 parts of N660 carbon black, 2 parts of stearic acid, 4 parts of octylphenol resin, 7 parts of 40MSF homogenizer, 3 parts of fatty acid resin, 1.5 parts of processing oil, 1.5 parts of accelerator DM, 3 parts of zinc oxide, and 0.6 parts of insoluble sulfur, by weight.

[0048] The first and second mastering steps include: adding 31 parts of natural rubber, 69 parts of brominated butyl rubber, 27 parts of butyl reclaimed rubber, 25 parts of light calcium carbonate, 67 parts of N660 carbon black, 2 parts of stearic acid, 4 parts of octylphenol resin, 7 parts of 40MSF homogenizer, 3 parts of fatty acid resin, and 1.5 parts of processing oil into an internal mixer for mixing to obtain a first-stage masterbatch. The first-stage masterbatch is then added to the internal mixer for a second-stage mastering process to obtain a second-stage masterbatch. The preferred discharge temperature of the first-stage masterbatch is 130℃, and the mixing time is ≥120s. The preferred discharge temperature of the second-stage masterbatch is 128℃.

[0049] The final mixing step includes: adding 1.5 parts of accelerator DM, 3 parts of zinc oxide, and 0.6 parts of insoluble sulfur to the masterbatch and then performing final mixing to obtain the final rubber compound. The discharge temperature of the final rubber compound is preferably 108°C to obtain the airtight layer rubber compound.

[0050] Example 4

[0051] This application provides a tubeless self-sealing tire. The composition and structure of the airtight tire are consistent with those of existing tubeless tires, including a tire carcass, a cord fabric, an outer tread, and an airtight rubber compound adhered to the inner layer of the tire.

[0052] Because the airtight rubber compound used is selected from the airtight rubber compound provided in Example 1 or 2, the airtight tire has low gas leakage and good flexural fatigue performance, and can effectively maintain tire pressure and air retention during vehicle operation.

[0053] Experimental Example 1

[0054] The experimental examples in this application are used to test the performance of the rubber compounds described in Examples 2-3, and to evaluate the improvement in the performance of the rubber compounds used in the tire airtight layer by using carbon black and pyrolysis carbon black compared with rubber compounds using only carbon black.

[0055] The testing process involved curing the rubber compounds provided in Examples 2-3 at 150°C for 35 minutes, and then testing the specimens for properties such as tensile stress, tensile strength, elongation at break, hardness, Payne effect, density, air permeability, and spherical rebound.

[0056] The test results are shown in Table 1. As can be seen from Table 1, compared with the rubber compound provided in Example 3, the airtightness (breathability), tensile stress, tensile strength, and spherical rebound of the airtight rubber compound provided in Example 2 of this application are about 10% better than those of the rubber compound provided in Example 3. At the same time, the elongation at break and hardness are similar to those of the rubber compound provided in Example 3. This indicates that the rubber compound formulation provided in this application uses a composite carbon black including both carbon black and pyrolysis carbon black, which can improve the density and physical and mechanical properties of the rubber compound with the same amount of addition. Furthermore, since the composite carbon black uses recycled pyrolysis carbon black, the amount of carbon black used is reduced, thereby reducing the preparation cost. This application provides a low-cost, high-airtightness rubber compound.

[0057] Table 1

[0058] Testing items Example 2 Example 3 100% constant tensile stress, MPa 107 100 300% constant tensile stress, MPa 112 100 Tensile strength, MPa 108 100 Elongation at break, % 95 100 hardness 96 100 Payne effect 122 100 density 100 100 <![CDATA[Air permeability, cm 3 ·m -2 ·d·pa]]> 110 100 Ball rebound (at 25°C), % 109 100

[0059] Table 1 uses the rubber compound described in Example 1 as a benchmark for comparison. The benchmark coefficient is 100. The larger the value, the better the performance.

[0060] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An airtight compound containing a pyrolytic carbon black having a wide particle size distribution, characterized in that, The raw rubber, the reinforcing filler, the active agent, the vulcanizing agent, the accelerator and the processing aid; The raw rubber is selected from natural rubber, brominated butyl rubber and butyl reclaimed rubber; The reinforcing filler is selected from composite carbon black and light calcium carbonate; The composite carbon black is selected from carbon black and pyrolysis carbon black; The active agent is selected from stearic acid; The vulcanizing agent is selected from insoluble sulfur and zinc oxide; The accelerator is selected from accelerator DM; The processing aid is selected from 40MSF homogenizing agent, octyl phenolic resin, fatty acid resin C5 and operating oil; The air tightness rubber comprises 31 parts by mass of natural rubber, 69 parts by mass of brominated butyl rubber, 27 parts by mass of butyl reclaimed rubber, 25 parts by mass of light calcium carbonate, 40 parts by mass of pyrolysis carbon black, 27 parts by mass of N660 carbon black, 2 parts by mass of stearic acid, 4 parts by mass of octyl phenolic resin, 7 parts by mass of 40MSF homogenizing agent, 3 parts by mass of fatty acid resin C5, 1.5 parts by mass of operating oil, 1.5 parts by mass of accelerator DM, 3 parts by mass of zinc oxide and 0.6 parts by mass of insoluble sulfur; The nitrogen adsorption specific surface area of the composite carbon black in the reinforcing filler is 30-100 m 2 / g, and the iodine absorption value is 30-140 g / kg.

2. An air tightness rubber containing a wide particle size distribution pyrolytic carbon black according to claim 1, characterized in that, The operating oil is aromatic operating oil and / or environmentally friendly operating oil.

3. Process for the production of air tight rubbers containing a broad particle size distribution pyrolytic carbon black according to any one of claims 1 to 2, characterized in that, The method comprises the steps of: S1. sequentially performing one-stage master mixing and two-stage master mixing on the raw rubber, the reinforcing filler, the active agent and the processing aid to obtain two-stage master mixed rubber; S2. performing final mixing on the two-stage master mixed rubber, the vulcanizing agent and the accelerator and discharging the rubber to obtain air tightness rubber.

4. A tubeless run-flat tire characterized by, The tire body, the cord fabric, the outer tire surface and the air tightness rubber containing wide particle size distribution pyrolysis carbon black according to any one of claims 1-2; The air tightness rubber is adhered to the inner layer of the tire body to form the air tightness layer of the tire.

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