Inflation-free inner tube rubber material and preparation method thereof

Abstract

The invention discloses an inflation-free inner tube rubber material and a preparation method thereof, and the inflation-free inner tube rubber material comprises the following components: 40-50 PHR of natural rubber, 40-50 PHR of high cis-butadiene rubber, 10-20 PHR of trans-isoprene rubber, 5-10 PHR of polyester fiber, 50-55 PHR of N550 carbon black, 2-5 PHR of zinc oxide, 3-5 PHR of an anti-aging agent, 2-5 PHR of stearic acid, 2-5 PHR of sulfur, and 0-2 PHR of an accelerant. According to the preparation method, an internal mixer F370 three-section operation mode is used, the inflation-free inner tube rubber material is obtained, a tire tread formula is subjected to production operation under the condition that performance requirements are met, and an obtained tire has excellent wear resistance, fatigue resistance, supporting performance and puncture resistance.

Description

Technical Field

[0001] The invention relates to the field of air-free tires, in particular to an air-free inner tube rubber material and a preparation method thereof. Background Art

[0002] At present, most two-wheeled vehicle tires on the market need to be inflated to support the tires in order to complete driving. Once the tires are punctured and deflated, they cannot drive normally. Therefore, it brings great troubles to the driver's driving safety and driving experience.

[0003] At present, there are some air-free one-piece tires on the market, but since they rely entirely on the hardness of rubber for support, there are a series of problems in actual application, such as the tire is too hard and the riding comfort is poor. The tire is easy to fall off the ring, causing safety accidents, and the rubber is poor in fatigue and easy to crack. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the inner tube needs to be inflated to support the outer tube in use, to avoid the problem of air leakage and tire blowout during use, and to propose an inflation-free inner tube rubber material and a preparation method thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A rubber compound for an inflation-free inner tube comprises the following components: 40-50 PHR of natural rubber, 40-50 PHR of high-cis butadiene rubber, 10-20 PHR of trans-isoprene rubber, 5-10 PHR of polyester fiber, 50-55 PHR of N550 carbon black, 2-5 PHR of zinc oxide, 3-5 PHR of antioxidant, 2-5 PHR of stearic acid, 2-5 PHR of sulfur and 0-2 PHR of accelerator.

[0007] As the preferred embodiment of the present invention, the weight proportions of the components are: 50 PHR of natural rubber, 40 PHR of high cis-butyl rubber, 20 PHR of trans-isoprene rubber, 10 PHR of polyester fiber, 50 PHR of N550 carbon black, 3 PHR of zinc oxide, 5 PHR of antioxidant (wherein antioxidant 4020 is 3 PHR and antioxidant RD is 2 PHR), 2 PHR of stearic acid, 3.5 PHR of sulfur and 1.2 PHR of accelerator.

[0008] A method for preparing a non-inflatable inner tube rubber material comprises the following steps:

[0009] Step S1, a masterbatch: an internal mixer of F370 is used, and the speed of the internal mixer is variable speed operation (50 rpm to 25 rpm). The internal mixer speed is 50 rpm to plasticize natural rubber, high cis-butyl rubber VCR412 and trans-isoprene rubber for 30 seconds, and then polyester fiber carbon black N550 is added and the speed is changed to 25 rpm after working for 30 seconds. Finally, the temperature displayed in the internal mixer reaches 155°C and then the material is discharged to make a masterbatch.

[0010] Step S2, second stage mixing: use an internal mixer F370, the internal mixer speed is constant speed operation (40 rpm), when the internal mixer speed shows 40 rpm, add the masterbatch and other small materials except the sulfur accelerator, clean up after 50 seconds of operation, and unload the materials after the internal mixer chamber temperature reaches 155°C to obtain the second stage mixed rubber.

[0011] Step S3, three-stage final refining: The final refining is performed using an F370 internal mixer at a speed of 25 rpm, after adding the second-stage mixed rubber, sulfur and accelerator, the rubber is refined for 50 minutes and then cleaned, and the material is unloaded at 95°C to obtain the airless inner tube rubber material (i.e., three-stage final refining).

[0012] As a preferred embodiment of the present invention, the two-stage mixed rubber obtained in step S2 needs to be left for 24 hours to be fully cooled before the three-stage final mixing in step S3 is carried out.

[0013] The beneficial effects of the present invention are:

[0014] 1. Through the use of the regular structure of high-cis butadiene rubber (VCR412) and the better comprehensive performance of natural rubber, 10-20 parts of trans-isoprene rubber with regular structure, easy crystallization and good fatigue resistance are used in the formula to ensure that the rubber produced has low heat generation and good fatigue resistance, solving the problem of easy crack damage when the tire is running with a lack of air. The reinforcing agent uses polyester fiber and N550 carbon black to solve the problem of tire support in the state of no air pressure.

[0015] 2. Trans-isoprene has the same chemical composition as natural rubber, but different cis and trans structures. Its molecular chain is highly regular, easy to crystallize, and has excellent wear resistance and fatigue resistance. High-cis butadiene rubber (VCR412) has a high cis structure, regular structural arrangement, and good rubber fatigue resistance, wear resistance and support. It provides excellent wear resistance, fatigue resistance and support for tires.

[0016] 3. The polyester fiber of the present invention is a material that is pre-treated to form masterbatch particles. The polyester fiber has good adhesion to rubber, can improve the strength of rubber, can improve the modulus of rubber, ensure the support of the tire, and at the same time its wear resistance and puncture resistance are also improved. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer, the implementation method of the present invention will be described in detail in combination with embodiments below, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0019] The present invention provides an air-free inner tube rubber compound and a preparation method thereof in an embodiment. The formula material is in the form of a three-stage operation of an internal mixer F370.

[0020] Step S1, a masterbatch: an internal mixer of F370 is used, and the speed of the internal mixer is variable speed operation (50 rpm to 25 rpm). The internal mixer speed is 50 rpm to plasticize natural rubber, high cis-butyl rubber VCR412 and trans-isoprene rubber for 30 seconds, and then polyester fiber carbon black N550 is added and the speed is changed to 25 rpm after working for 30 seconds. Finally, the temperature displayed in the internal mixer reaches 155°C and then the material is discharged to make a masterbatch.

[0021] Step S2, second stage mixing: use an internal mixer F370, the internal mixer speed is constant speed operation (40 rpm), when the internal mixer speed shows 40 rpm, add the masterbatch and other small materials except the sulfur accelerator, clean up after 50 seconds of operation, and unload the materials after the internal mixer chamber temperature reaches 155°C to obtain the second stage mixed rubber.

[0022] Step S3, three-stage final refining: The final refining is performed using an F370 internal mixer at a speed of 25 rpm, after adding the second-stage mixed rubber, sulfur and accelerator, the rubber is refined for 50 minutes and then cleaned, and the material is unloaded at 95°C to obtain the airless inner tube rubber material (i.e., three-stage final refining).

[0023] Preparation method of air-free inner tube rubber of embodiment and comparative example:

[0024] First, the raw materials are mixed according to the raw material ratio shown in Table 1. Then, the first-stage masterbatch is prepared by mixing all rubbers (trans-isoprene rubber, high-cis butadiene rubber VCR412) and fillers (polyester fiber, N550) to obtain the first-stage masterbatch. The second-stage masterbatch and all the weighed additives (zinc oxide, antioxidant, stearic acid) except sulfur and accelerator are put into an internal mixer for mixing. When the temperature reaches 155°C, the mixed rubber is discharged from the internal mixer to obtain the second-stage mixed rubber. After the second-stage mixed rubber is parked for 24 hours to be fully cooled, sulfur and accelerator are added, and the rubber is mixed for 50 minutes and cleaned. After 95°C, the material is discharged to obtain the air-free inner tube rubber compound (i.e., the third-stage final mixing).

[0025] Table 1 Raw material ratios of the embodiments and comparative examples

[0026] Material Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 SCR5 40 40 50 40 50 50 BR9000 0 0 0 0 0 50 VCR412 50 40 40 50 50 0 Trans-isoprene gum 10 20 10 10 0 0 Polyester 5 5 10 0 5 5 N550 55 55 50 60 55 55 Zinc Oxide 3 3 3 3 3 3 Stearic acid 2 2 2 2 2 2 4020 3 3 3 3 3 3 RD 2 2 2 2 2 2 Sulfur 3.5 3.5 3.5 3.5 3.5 3.5 NS 1.2 1.2 1.2 1.2 1.2 1.2

[0027] The rubber obtained in the examples and comparative examples was tested by a thermal dynamic analyzer DMA, and the test items included Tan δ at 80°C. The Shore hardness, tensile strength, elongation, elongation, resilience, compression deformation, and compression heat generation test standards of the rubber were:

[0028] Shore hardness test standard GB / T 531.1-2008 / ISO 7619-1, tensile strength, elongation and elongation test standard (HB / T 2198-2011), resilience test GB / T 1681-2009, Goodrich compression heat test of final fatigue, laboratory endurance running performance of tires (according to GB / T 4570-2022), actual vehicle mileage test of tires 20,000 kilometers.

[0029] Table 2 Rubber properties of the embodiments and comparative examples

[0030]

[0031] The test results of the rubber properties of the embodiments and comparative examples are shown in Table 2. Among them: 1. The final fatigue temperature rise of the Goodrich compression heating test was reduced from the existing 25°C to 20°C.

[0032] 2. Under the test conditions of pressure 15Pa, temperature 50℃ and time 6 hours, the compression deformation is reduced from 1.1% to 0.8%.

[0033] 3. The tire's laboratory durability performance (according to GB / T 4570-2022) is qualified.

[0034] 4. The actual vehicle mileage test was 20,000 kilometers with no abnormalities.

[0035] 5. Rubber rebound test GB / T 1681-2009 improved by 33%.

[0036] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, the above embodiments are only preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and embodiments, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A rubber compound for an air-free inner tube, characterized in that: The invention comprises the following components: natural rubber 40-50PHR, high cis-butyl rubber 40-50PHR, trans-isoprene rubber 10-20PHR, polyester fiber 5-10PHR, N550 carbon black 50-55PHR, zinc oxide 2-5PHR, antioxidant 3-5PHR, stearic acid 2-5PHR, sulfur 2-5PHR and accelerator 0-2PHR.

2. The air-free inner tube rubber material according to claim 1, characterized in that: The weight proportions of each component are: 50 PHR of natural rubber, 40 PHR of high cis-butyl rubber, 20 PHR of trans-isoprene rubber, 10 PHR of polyester fiber, 50 PHR of N550 carbon black, 3 PHR of zinc oxide, 5 PHR of antioxidant (including 3 PHR of antioxidant 4020 and 2 PHR of antioxidant RD), 2 PHR of stearic acid, 3.5 PHR of sulfur and 1.2 PHR of accelerator.

3. A method for preparing a non-inflatable inner tube rubber compound as claimed in any one of claims 1-2, characterized in that: The steps include: Step S1, a masterbatch: the speed of the internal mixer is variable, the internal mixer speed is 50 rpm to plasticize the natural rubber, high cis-butyl rubber and trans-isoamyl rubber for 30 seconds, and then the polyester fiber carbon black N550 is added and the speed is changed to 25 rpm after the operation for 30 seconds, and finally the temperature in the internal mixer reaches 155° C. and then the material is discharged to make a masterbatch; Step S2, second-stage mixing: the internal mixer is operated at a constant speed of 40 rpm. When the internal mixer speed shows 40 rpm, the masterbatch and other small materials except the sulfur accelerator are added. After 50 seconds of operation, the mixing chamber is cleaned up. After the temperature of the internal mixer chamber reaches 155° C., the materials are discharged to obtain the second-stage mixed rubber. Step S3, three-stage final refining: the rotation speed is operated at a constant speed of 25 rpm, the second-stage mixed rubber, sulfur and accelerator are added, and the rubber is refined for 50 minutes and cleaned, and the material is unloaded at 95°C to obtain the non-inflation inner tube rubber material.

4. The method for preparing a non-inflatable inner tube rubber compound according to claim 3, characterized in that: The two-stage mixed rubber obtained in step S2 needs to be left for 24 hours to be fully cooled before the three-stage final mixing in step S3 is carried out.

5. The method for preparing a non-inflatable inner tube rubber compound according to claim 4, characterized in that: The internal mixer is a F370 internal mixer.

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