Engineering radial tire airtight layer and its production process and its tear resistance performance testing method

Abstract

The present invention discloses an airtight layer of an engineering radial tire, a production process thereof, and a method for detecting its tear resistance, and relates to the field of tire technology. The technical solution is as follows: (1) the airtight layer comprises the following components in parts by weight: 60-80 parts of brominated butyl rubber, 10-15 parts of natural rubber, 10-15 parts of chlorosulfonated polyethylene, and 55-60 parts of carbon black; (2) the exhaust line groove of the vulcanization bladder is arc-shaped, with a depth h'=1.65-1.8mm, a width W'=7.5-7.8mm, a surface chamfer R1'=3.2-3.5mm, a groove bottom chamfer R2'=1.5-1.8mm, and a groove cross-sectional area of 5.5-6mm. 2 The present invention adjusts the formula design of the tire airtight layer, increases the tear resistance of the airtight layer, improves the size design of the exhaust line of the vulcanizing bladder, can extend the service life of the vulcanizing bladder, and reduce aging and cracking at the groove position of the vulcanizing bladder.

Description

Technical Field

[0001] The present invention relates to the technical field of tires, and in particular to an airtight layer of an engineering radial tire, a production process thereof, and a method for detecting the tear resistance thereof. Background Art

[0002] At present, there are the following problems in the production process of engineering radial tires: Due to the imperfect formula design and the insufficient design of the bladder exhaust line during the vulcanization process, the tire is prone to problems when running in a high temperature and high humidity environment. Specifically, in the middle and late stages of tire use, the airtight layer at the root of the exhaust line in the tire (such as Figure 1 As shown in the figure, cracks will appear, and the occurrence of such cracks will directly lead to tire failures such as air leakage and delamination, which will seriously affect the performance of the tire.

[0003] It's worth noting that this problem gradually manifests itself during tire use, causing significant inconvenience to users. Furthermore, the current lack of reasonable and effective simulation testing methods makes it impossible to accurately identify and effectively improve the tear resistance of the finished tire's innerliner during production. This undoubtedly increases the difficulty of tire quality control and further affects the overall tire mileage.

[0004] To address this issue, there's an urgent need to optimize the existing tire innerliner formulation and improve the design of the bladder exhaust lines during the vulcanization process to reduce the likelihood of cracks when the tire operates in high-temperature and high-humidity environments. Furthermore, developing a scientific and rational simulation testing method to effectively identify and improve the tear resistance of the finished tire's innerliner is key to improving tire quality and extending its service life. Only in this way can we provide our customers with safer and more reliable tires, ensuring driving safety. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to overcome the shortcomings of the existing technology, provide an engineering radial tire airtight layer and its production process and its tear resistance testing method, adjust the formula design of the tire airtight layer, and improve the tear resistance of the airtight layer; improve the exhaust line size design of the vulcanization bladder, which can extend the service life of the vulcanization bladder and reduce aging and cracking at the groove position of the vulcanization bladder.

[0006] The technical solution of the present invention is:

[0007] In a first aspect, the present invention provides a production process for an airtight layer of an engineering radial tire, wherein: (1) the airtight layer comprises the following components in parts by weight: 60-80 parts of brominated butyl rubber, 10-15 parts of natural rubber, 10-15 parts of chlorosulfonated polyethylene, and 55-60 parts of carbon black; and (2) the exhaust line groove of the vulcanization bladder is arc-shaped, with a depth h'=1.65-1.8 mm, a width W'=7.5-7.8 mm, a surface chamfer R1'=3.2-3.5 mm, a groove bottom chamfer R2'=1.5-1.8 mm, and a groove cross-sectional area of 5.5-6 mm. 2 .

[0008] In a second aspect, the present invention provides an engineering radial tire airtight layer produced by the above-mentioned engineering radial tire airtight layer production process.

[0009] In a third aspect, the present invention provides a method for testing the tear resistance of the airtight layer of the above-mentioned engineering radial tire, wherein a rubber flexure tester is used in a constant temperature and humidity test chamber to test the tear resistance of the airtight layer sample at different temperatures and humidities.

[0010] Preferably, the detection temperature is 60-80°C, and the detection humidity is 60-80%RH.

[0011] Preferably, the rubber flexure testing machine is placed in a constant temperature and humidity test box, and the constant temperature and humidity test box is also provided with a temperature sensor, a humidity sensor, a temperature regulator and a humidity regulator.

[0012] Preferably, the airtight layer sample is subjected to a reciprocating motion of 280-300 times / min on a rubber flexure testing machine.

[0013] Preferably, during the test, a rubber flexure tester is used to test at least six airtight layer samples simultaneously.

[0014] Preferably, during the test, twelve airtight layer samples are tested simultaneously using a rubber flexure testing machine.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention adjusts the formula design of the tire airtight layer, thereby increasing the tear resistance of the airtight layer; improves the size design of the exhaust line of the vulcanization bladder, thereby extending the service life of the vulcanization bladder and reducing aging and cracking at the groove position of the vulcanization bladder; in addition, the establishment of a method for detecting the tear resistance of the airtight layer can realize flexural stretching of the test rubber compound under conditions of 60-80°C and 60-80% RH, simulating the actual operating conditions of the engineering tire, and evaluating the changes in the tear resistance of the adjusted airtight layer under different temperature and humidity conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a schematic diagram of the structure of the airtight layer of an engineering radial tire.

[0018] Figure 2 It is a structural schematic diagram of the exhaust line groove of the vulcanizing bladder of the present invention.

[0019] Figure 3 It is a structural schematic diagram of the constant temperature and humidity test box and the rubber flexure tester in the present invention.

[0020] Figure 4 The present invention is a schematic diagram of the structure of the exhaust line groove of the existing vulcanizing bladder.

[0021] In the figure, 1. Airtight layer; 2. Exhaust line groove; 3. Constant temperature and humidity test chamber; 4. Rubber flexure testing machine; 5. Temperature sensor; 6. Humidity sensor; 7. Temperature regulator; 8. Humidity regulator. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0023] Comparative Example 1

[0024] The airtight layer of Comparative Example 1 includes the following components in parts by weight: 80 parts of brominated butyl rubber, 20 parts of chlorosulfonated polyethylene, and 50 parts of carbon black.

[0025] like Figure 4 As shown in the airtight layer sample of Comparative Example 1, the exhaust line dimensions of the curing bladder are designed as follows: the exhaust line groove is cylindrical, with a depth of h = 2 mm, a width of W = 3 mm, a surface chamfer R1 = 0.3 mm, a groove bottom chamfer R2 = 1 mm, and a groove cross-sectional area of 5.61 mm 2 .

[0026] Comparative Example 2

[0027] The airtight layer of Comparative Example 2 includes the following components in parts by weight: 80 parts of brominated butyl rubber, 10 parts of natural rubber, 10 parts of chlorosulfonated polyethylene, and 55 parts of carbon black.

[0028] like Figure 4 As shown in the airtight layer sample of Comparative Example 2, the exhaust line dimensions of the curing bladder are designed as follows: the exhaust line groove is cylindrical, with a depth of h = 2 mm, a width of W = 3 mm, a surface chamfer R1 = 0.3 mm, a groove bottom chamfer R2 = 1 mm, and a groove cross-sectional area of 5.61 mm 2 .

[0029] Comparative Example 3

[0030] The airtight layer of Comparative Example 3 includes the following components in parts by weight: 80 parts of brominated butyl rubber, 20 parts of chlorosulfonated polyethylene, and 50 parts of carbon black.

[0031] like Figure 2 As shown, in the airtight layer sample of comparative example 1, the exhaust line size of the curing bladder is designed as follows: the exhaust line groove is arc-shaped, the airtight layer sample size is as follows: the depth h'=1.7mm, the width W'=7.7mm, the surface chamfer R1'=3.3mm, the groove bottom chamfer R2'=1.7mm, and the groove cross-sectional area is 5.8mm 2 .

[0032] Example 1

[0033] The airtight layer of Example 1 includes the following components in parts by weight: 80 parts of brominated butyl rubber, 10 parts of natural rubber, 10 parts of chlorosulfonated polyethylene, and 55 parts of carbon black.

[0034] like Figure 2 As shown, in the airtight layer sample of Example 1, the exhaust line dimensions of the curing bladder are designed as follows: the exhaust line groove is arc-shaped, the airtight layer sample dimensions are: depth h'=1.7mm, width W'=7.7mm, surface chamfer R1'=3.3mm, groove bottom chamfer R2'=1.7mm, and groove cross-sectional area is 5.8mm 2 .

[0035] Example 2

[0036] The airtight layer of Example 2 includes the following components in parts by weight: 80 parts of brominated butyl rubber, 10 parts of natural rubber, 10 parts of chlorosulfonated polyethylene, and 55 parts of carbon black.

[0037] like Figure 2 As shown, in the airtight layer sample of Example 2, the exhaust line dimensions of the curing bladder are designed as follows: the exhaust line groove is arc-shaped, the airtight layer sample dimensions are: depth h'=1.65mm, width W'=7.5mm, surface chamfer R1'=3.2mm, groove bottom chamfer R2'=1.5mm, and groove cross-sectional area is 5.5mm 2 .

[0038] Example 3

[0039] The airtight layer of Example 3 includes the following components in parts by weight: 80 parts of brominated butyl rubber, 15 parts of natural rubber, 15 parts of chlorosulfonated polyethylene, and 60 parts of carbon black.

[0040] like Figure 2As shown, in the airtight layer sample of Example 3, the exhaust line dimensions of the curing bladder are designed as follows: the exhaust line groove is arc-shaped, the airtight layer sample dimensions are: depth h'=1.8mm, width W'=7.8mm, surface chamfer R1'=3.5mm, groove bottom chamfer R2'=1.8mm, and groove cross-sectional area is 6mm 2 .

[0041] Take 6 airtight layer samples from Comparative Examples 1-3 and Examples 1-3, and place them in Figure 3 The rubber flexure tester (GOTECH High-Speed Rail Testing Instrument GT-7011-DM) in the constant temperature and humidity test chamber shown in the figure is equipped with a temperature sensor, humidity sensor, temperature regulator, and humidity regulator. Tear resistance tests were conducted under standard operating conditions of 60°C and 60% RH, and high-temperature and high-humidity conditions of 80°C and 80% RH. During the tests, the innerliner specimens were reciprocated in the rubber flexure tester at a rate of 300 cycles per minute to simulate the changes in the innerliner's tear resistance under different operating conditions. The test results are shown in Table 1:

[0042] Table 1 Test results of tear resistance of airtight layer samples of Comparative Examples 1-3 and Examples 1-3 under different working conditions

[0043]

[0044] Comparative Examples 1 and 2 in Table 1 show that, under normal operating conditions, the innerliner formulation of Example 1 of the present invention increases the average tear strength of the innerliner by 6% compared to existing innerliner formulations, and by 5.9% under high-temperature, high-humidity operating conditions. This is because, compared to Comparative Example 1, Comparative Example 2 increases the tear resistance of the innerliner compound by adding 10 parts of natural rubber, while simultaneously ensuring that the innerliner's gas retention is not compromised by the addition of 5 parts of carbon black. Comparative Example 3, compared to Comparative Example 1, shows that, under normal operating conditions, the average tear strength of the innerliner increases by 3.1% with the design of the vent line of the present invention compared to the design of the vent line of the existing curing bladder, and by 3.5% under high-temperature, high-humidity operating conditions. This is because, compared to Comparative Example 1, Comparative Example 3 reduces stress concentration at the base of the tire innerliner's vent line by reducing the groove depth and increasing the groove surface chamfer, thereby reducing the risk of innerliner rupture during use of the finished tire. Furthermore, the increased vent line width ensures that the groove's cross-sectional area is not reduced, thereby preventing any impact on venting during the actual tire vulcanization process. As can be seen from Examples 1-3 and Comparative Example 1, under normal operating conditions, the average tear strength of the innerliner is increased by 8-8.6% when using the vent line design and innerliner formulation of the present curing bladder, compared to existing curing bladders with vent line dimensions and existing innerliner formulations. Under high temperature and high humidity conditions, the average tear strength of the innerliner is increased by 8.9-9.1%.

[0045] In summary, the present invention can improve the tear resistance of the airtight layer under normal working conditions and high temperature and high humidity working conditions by redesigning the airtight layer formula and the exhaust line size of the curing bladder.

Claims

1. The production process of the inner liner of an engineering radial tire is characterized by: (1) The airtight layer comprises the following components in parts by weight: 60-80 parts of brominated butyl rubber, 10-15 parts of natural rubber, 10-15 parts of chlorosulfonated polyethylene, and 55-60 parts of carbon black; (2) The exhaust line groove of the curing bladder is arc-shaped, with a depth of h'=1.65-1.8mm, a width of W'=7.5-7.8mm, a surface chamfer R1'=3.2-3.5mm, a groove bottom chamfer R2'=1.5-1.8mm, and a groove cross-sectional area of 5.5-6mm 2 .

2. The engineering radial tire airtight layer produced by the engineering radial tire airtight layer production process according to claim 1.

3. The method for testing the tear resistance of the inner liner of an engineering radial tire according to claim 2, wherein: In a constant temperature and humidity test chamber, a rubber flexure tester was used to test the tear resistance of the inner liner samples under different temperatures and humidity.

4. The method for testing the tear resistance of the inner liner of an engineering radial tire according to claim 3, wherein: The detection temperature is 60-80°C, and the detection humidity is 60-80% RH.

5. The method for testing the tear resistance of the inner liner of an engineering radial tire according to claim 3, wherein: The rubber flexure testing machine is placed in a constant temperature and humidity test box, and the constant temperature and humidity test box is also provided with a temperature sensor, a humidity sensor, a temperature regulator and a humidity regulator.

6. The method for testing the tear resistance of the inner liner of an engineering radial tire according to claim 3, wherein: The airtight layer sample is subjected to a reciprocating motion of 280-300 times / min on a rubber flexure testing machine.

7. The method for testing the tear resistance of the inner liner of an engineering radial tire according to claim 3, wherein: During the test, a rubber flexure tester is used to test at least six airtight layer specimens simultaneously.

8. The method for testing the tear resistance of the inner liner of an engineering radial tire according to claim 7, wherein: During the test, a rubber flexure testing machine was used to test twelve airtight layer samples simultaneously.

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