A method, device and software for characterizing the balance between wet traction and rolling resistance of tread rubber

Abstract

This application relates to the technical field of tire material design, and particularly to a method, device, software for characterizing the balance between wet grip and rolling resistance of a tire tread compound, and a tire tread compound obtained by this method. A method for characterizing the balance between wet grip and rolling resistance of a tire tread compound, which finds a method using the shape of the tanδ-Temperature curve to characterize the wet grip and rolling resistance of the tire tread compound at a certain glass transition temperature (Tg) and filler dosage. Under the guidance of the method of this invention, no matter how the various material ratios in the rubber compound are adjusted, as long as the requirements of this application are met, tires with low rolling resistance and high wet grip can be produced.

Description

Technical Field

[0001] This application relates to the technical field of tire material design, and particularly relates to a method, device, software for characterizing the balance between wet grip and rolling resistance of a tire tread compound, and a tire tread compound obtained by this method. Background Art

[0002] The labeling method of tires puts forward requirements for the wet grip and rolling resistance of tires. As the part of the tire with the largest weight and volume, the tire tread accounts for more than 50% of the rolling resistance of the tire. On the other hand, as the only part in contact with the ground, the tread directly determines the wet grip ability of the tire. Therefore, when designing the tread compound formula, which factors affect the grip ability and rolling resistance is one of the research focuses of safe and energy-saving tires.

[0003] Generally, in the temperature scan of a dynamic mechanical analyzer (DMA), engineers often use the loss factor (tanδ) to characterize rolling resistance and wet grip. As mentioned in the invention patent CN101792545B, the tanδ at 0°C is used to characterize wet grip, and the tanδ at 60°C is used to characterize rolling resistance. In the invention, in order to achieve excellent and balanced wet grip and rolling resistance, the tanδ at 60°C is required to be designed between 0.11 and 0.14, and the tanδ at 0°C is higher than 0.35. Another example is mentioned in the invention patent CN106750668B, where the tanδ at 0°C is made 0.514 and the tanδ at 60°C is made 0.079, and finally a tire with both rolling resistance and wet grip reaching Class A is produced. Furthermore, in addition to regulating the tanδ at the above two temperatures, some newer patents also mention other regulation methods for these two values. As mentioned in the patent WO2020243304A1, in order to ensure rolling resistance and grip, the tanδ value at 0°C is at least 1.5 times that of the tanδ at 60°C, preferably between 1.5 and 2 times that of the tanδ at 60°C.

[0004] However, in the applicant's research, it is found that when there are multiple peaks in the tanδ curve (such as CN107614593A), or when the amount of filler in the tread compound is small and the peak of tanδ is high, using the above tanδ regulation means to characterize rolling resistance and wet grip is no longer accurate. With the rise of the new energy vehicle industry, the rolling resistance (long driving range) and wet grip ability of tires have received more extensive attention. For this reason, the applicant has conducted a large number of studies on the filler dosage in the tread compound and the tanδ-Temperature curve of DMA, and invented a method for characterizing the balance between wet grip and rolling resistance of a tire tread compound. Summary of the Invention

[0005] To solve the above technical problems, the purpose of this application is to provide a method for characterizing the balance between wet grip and rolling resistance of a tire tread compound. Under certain glass transition temperature (Tg) and filler dosage, this method finds a way to use the shape of the tanδ-Temperature curve to characterize the wet grip and rolling resistance of the tire tread compound. Under the guidance of the method of this invention, no matter how the various material ratios in the rubber compound are adjusted, as long as the requirements of this application are met, tires with low rolling resistance and high wet grip can be produced.

[0006] To achieve the above purpose, this application adopts the following technical solutions:

[0007] A method for characterizing the balance between wet grip and rolling resistance of a tire tread compound, the method comprising the following steps:

[0008] 1) Conduct a temperature scanning experiment on the vulcanized rubber of the tire tread using a dynamic mechanical scanner;

[0009] 2) Perform data processing on the obtained DMA curve:

[0010] ① Find the point corresponding to 60°C on the curve, draw a line parallel to the abscissa, and intersect the curve at points b and c;

[0011] ② Find the peak vertex a of the tanδ curve, draw a line perpendicular to the ordinate, and intersect the line segment bc at point d. The height of this line segment ad is denoted as H;

[0012] ③ Find the midpoint o of the line segment ad, draw a line parallel to the abscissa, and intersect the curve at points e and f. The length of the line segment ef is denoted as W;

[0013] ④ Define the balance index WRI of the wet grip and rolling resistance of the tire tread compound. The calculation formula of WRI is as follows:

[0014] WRI = H * 100 / W 0.9

[0015] When WRI < 2.5, the tire using this tire tread compound has better wet grip ability.

[0016] When WRI > 4.5, the tire using this tire tread compound has lower rolling resistance.

[0017] When 2.5 ≤ WRI ≤ 4.5, the tire has excellent balance between wet grip and rolling resistance.

[0018] Preferably, the working parameters of the dynamic mechanical scanner are as follows:

[0019] Frequency: 20 Hz;

[0020] Static strain: 10%;

[0021] The dynamic strain adopts variable strain: when the scanning temperature is from -60°C to 10°C, the dynamic strain is ±0.25%; when the scanning temperature is from 10°C to 80°C, the dynamic strain is ±1%.

[0022] Preferably, in step 2), EXCEL or ORIGIN software is used for data processing.

[0023] Furthermore, the present application also provides a device for characterizing the balance of wet grip and rolling resistance of a tire tread rubber. The device includes a dynamic mechanical scanner and a computer device. The computer device collects data from the dynamic mechanical scanner. The computer device includes a memory, a processor, and a computer program stored on the memory. It is characterized in that the processor executes the computer program to implement the method.

[0024] Furthermore, the present application also provides a computer device, including a memory, a processor, and a computer program stored on the memory. The processor executes the computer program to implement the method.

[0025] Furthermore, the present application also provides a computer-readable storage medium, on which a computer program or instruction is stored. When the computer program or instruction is executed by a processor, the method is implemented.

[0026] Furthermore, the present application also provides a computer program product, including a computer program or instruction. When the computer program or instruction is executed by a processor, the method is implemented.

[0027] Furthermore, the present application also provides a tire tread rubber with balanced wet grip and rolling resistance. It is characterized in that the tread rubber is detected by the method, and 2.5 ≤ WRI ≤ 4.5.

[0028] Preferably, the tread rubber is composed of one or more olefin rubbers. When multiple rubbers are used, there can only be a single peak in the tanδ-Temperature curve; and the peak value of the tanδ-Temperature curve used to characterize the Tg of the tread rubber needs to satisfy -30°C ≤ Tg ≤ 0°C; calculated based on 100 phr of the rubber weight in the formula, 40 phr ≤ filler dosage ≤ 200 phr; more preferably, the rubber is one or more of natural rubber, cis-butadiene rubber, and styrene-butadiene rubber; more preferably, the filler is selected from one or more of carbon black, silica, clay, and calcium carbonate.

[0029] Furthermore, the present application also provides a tire with balanced wet grip and rolling resistance. The tread rubber used in the tire is detected by the method, and 2.5 ≤ WRI ≤ 4.5.

[0030] The principle of this application is as follows: The length H of line segment ad is related to the dispersion of the filler in the rubber. Generally speaking, the larger the value of H, the better the filler dispersion, and the rolling resistance of the tread rubber is low, but too high will have an adverse impact on wet traction. On the other hand, the length W of line segment ef is related to the compatibility of materials such as rubber, softening oil, and resin, as well as the molecular weight and molecular weight distribution of the rubber. Generally speaking, the larger the value of W, the better the compatibility of the rubber materials, and it shows better wet traction resistance, but too large a value of W will have a deteriorating impact on the rolling resistance of the tire. After a large number of experiments and verifications, the above WRI value has finally been determined. When the WRI value is between 2.5 and 4.5, a tread rubber with excellent balance between wet traction and rolling resistance can be designed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the tanδ-Temperature curve graph of this application.

[0032] Figure 2 It is the tanδ-Temperature curve graph of Comparative Example 1, Example 6, and Example 8 of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] When selecting the tread rubber of the tire of this application, the following preconditions are met:

[0034] 1) A tread rubber of a tire, which can be composed of one or more olefin rubbers, such as natural rubber, cis-butadiene rubber, styrene-butadiene rubber, etc. However, when using multiple rubbers, there can only be a single peak in the tanδ-Temperature curve, and there cannot be more than two peaks. This means that the multiple rubbers are basically completely compatible.

[0035] 2) The peak value of the tanδ-Temperature curve used to characterize the Tg of the tread rubber needs to satisfy -30°C ≤ Tg ≤ 0°C.

[0036] 3) The fillers added to the tread rubber can be fillers such as carbon black, silica, clay, calcium carbonate, etc., but the amount used by weight (calculated based on 100 phr of the weight of the rubber in the formula) needs to satisfy 40 phr ≤ filler dosage ≤ 200 phr.

[0037] Through the above conditions, 11 types of tread rubbers are selected for this application, and all the tread rubbers are subjected to a temperature sweep experiment of DMA after vulcanization. Frequency: 20 Hz; Static strain: 10%. The dynamic strain uses variable strain: when the scanning temperature is from -60°C to 10°C, the dynamic strain is: ±0.25%; when the scanning temperature is from 10°C to 80°C, the dynamic strain is: ±1%.

[0038] According to the test results, the tanδ values at 0°C and 60°C, and the DMA curve are obtained.

[0039] For the tread compounds of Examples 1-7, the peak of the tanδ-Temperature curve used to characterize Tg satisfies -30°C ≤ Tg ≤ 0°C, and 40 phr ≤ filler dosage ≤ 200 phr. By contrast, for the tread compound of Comparative Example 1, Tg > 0°C, for Comparative Example 2, no filler is contained, and for Comparative Example 3, 15 parts of filler are added.

[0040] For the DMA curve, data processing is performed using EXCEL or ORIGIN software (refer to the following Figure 1 ):

[0041] ① Find the point corresponding to 60°C on the curve, draw a line parallel to the abscissa, and the line intersects the curve at two points b and c;

[0042] ② Find the peak vertex a of the tanδ curve, draw a line perpendicular to the ordinate, and the line intersects the line segment bc at point d, and the height of this line is denoted as H;

[0043] ③ Find the midpoint o of the line segment ad, draw a line parallel to the abscissa, and the line intersects the curve at two points e and f, and the length of the line segment ef is denoted as W;

[0044] ④ Calculate the wet grip and rolling resistance balance index WRI of the tread compound, WRI = H * 100 / W 0.9 .

[0045] The above 11 tread compounds are made into tires, made into 205 / 55R16 tires, and the rolling resistance coefficient of the tires is tested using ISO28580, and the wet grip coefficient of the tires is tested using Regulation 117.

[0046]

[0047]

[0048] The above is the description of the embodiments of the present application. Through the above description of the disclosed embodiments, those skilled in the art can implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel points disclosed herein.

Claims

1. A method for characterizing the balance between wet grip and rolling resistance of a tire tread rubber, characterized in that, the method comprises the following steps: 1) Conduct a temperature scanning experiment on the vulcanized rubber of the tread using a dynamic mechanical scanner; 2) Perform data processing on the obtained DMA curve: ① Locate the point corresponding to 60 °C on the curve, draw a line parallel to the abscissa, and intersect the curve at two points b and c; ② Locate the peak vertex a of the tanδ curve, draw a line perpendicular to the ordinate, and intersect the line segment bc at point d. The height of this line segment ad is denoted as H; ③ Locate the midpoint o of the line segment ad, draw a line parallel to the abscissa, and intersect the curve at two points e and f. The length of the line segment ef is denoted as W; ④ Define the balance index WRI of the wet grip and rolling resistance of the tread rubber. The calculation formula of WRI is as follows: WRI = H * 100 / W 0.9 , When 2.5 ≤ WRI ≤ 4.5, the tire has a balance between wet grip and rolling resistance.

2. A method for characterizing the balance between wet grip and rolling resistance of a tire tread rubber according to claim 1, characterized in that, the working parameters of the dynamic mechanical scanner are as follows: Frequency: 20 Hz; Static strain: 10%; The dynamic strain adopts variable strain: when the scanning temperature is between -60 °C and 10 °C, the dynamic strain is: ±0.25%; when the scanning temperature is between 10 °C and 80 °C, the dynamic strain is: ±1%.

3. A method for characterizing the balance between wet grip and rolling resistance of a tire tread rubber according to claim 1, characterized in that, Step 2) uses EXCEL or ORIGIN software for data processing.

4. A device for characterizing the balance between wet grip and rolling resistance of a tire tread rubber, characterized in that, the device comprises a dynamic mechanical scanner and a computer device. The computer device collects the data of the dynamic mechanical scanner. The computer device comprises a memory, a processor, and a computer program stored on the memory. It is characterized in that the processor executes the computer program to implement the method according to any one of claims 1-3.

5. A computer device, comprising a memory, a processor, and a computer program stored on the memory, characterized in that, the processor executes the computer program to implement the method according to any one of claims 1-3.

6. A computer-readable storage medium, on which a computer program or instruction is stored, characterized in that, when the computer program or instruction is executed by a processor, it implements the method according to any one of claims 1-3.

7. A computer program product, comprising a computer program or instruction, characterized in that, when the computer program or instruction is executed by a processor, it implements the method according to any one of claims 1-3.

8. A tire tread rubber with balanced wet grip and rolling resistance, characterized in that, the tread rubber is detected by the method according to any one of claims 1-3, wherein 2.5 ≤ WRI ≤ 4.

5.

9. The tire tread rubber according to claim 8, characterized in that, The tread compound is composed of one or more olefin rubbers. When multiple rubbers are used, there can only be a single peak in the tanδ-Temperature curve. Moreover, the peak value of the tanδ-Temperature curve used to characterize the Tg of the tread compound satisfies -30°C ≤ Tg ≤ 0°C. Calculated based on 100 phr of the rubber weight fraction in the formulation, 40 phr ≤ filler dosage ≤ 200 phr.

10. The tire tread compound according to claim 9, characterized in that the rubber is one or more of natural rubber, cis-1,4-polybutadiene rubber, and styrene-butadiene rubber.

11. The tire tread compound according to claim 9, characterized in that the filler is selected from one or more of carbon black, silica, clay, and calcium carbonate.

12. A tire with balanced anti-wet grip and rolling resistance, characterized in that the tread compound used in this tire is the tire tread compound according to any one of claims 8-11.

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