A rubber material for improving the durability of semi-steel tires and a preparation method thereof

Abstract

The present invention discloses a rubber material and a preparation method thereof for improving the durability of a semi-steel tire, wherein the rubber material comprises the following components in parts by weight: 75-85 parts of natural rubber; 5-10 parts of butadiene-styrene rubber; 5-15 parts of rare earth cis-butadiene rubber; 5-10 parts of zinc oxide; 1-2 parts of stearic acid; 30-40 parts of N330 carbon black; 30-40 parts of N660 carbon black; 4.5-6 parts of phenolic reinforcing resin; 1-2 parts of tert-butyl tackifying resin; 2-4 parts of antioxidant; 2-3.5 parts of accelerator; 3-5 parts of insoluble sulfur. The rubber material proposed by the present invention has high hardness and low heat generation characteristics, and the Mooney viscosity of the rubber material is effectively controlled by a multi-step mixing method, avoiding the frosting phenomenon that may occur in the extrusion process. By introducing rare earth cis-butadiene rubber and two carbon blacks of different particle sizes, not only the fatigue resistance of the rubber material is improved, but also the rubber material is ensured to have a higher hardness while reducing heat generation. Ultimately, the application of this new rubber compound allows the tire to maintain good rigidity while greatly improving the durability of the tire.

Description

Technical Field

[0001] The invention belongs to the technical field of tire materials, and in particular relates to a rubber material for improving the durability of a semi-steel tire and a preparation method thereof. Background Art

[0002] In existing tire manufacturing technology, in order to improve tire durability, the tire structure is usually adjusted, such as improving the design of the tire belt layer and enhancing the carcass strength. In addition, optimizing the formula of each tire component to reduce the heat generation performance of the material is also a common practice. However, most of these improvement measures focus on single structural improvements or optimization of rubber formulas, and do not involve overall innovation of tire structure.

[0003] Specifically, existing methods for improving tire durability mainly include adjusting the structure of the tire belt layer, enhancing the strength of the tire body, or improving the formula of various tire components to reduce the accumulation of heat inside the rubber, thereby extending the service life of the tire. However, these methods do not solve the problem of overall tire structural innovation, that is, how to significantly improve the durability of the tire through the application of new materials and technological innovation without changing the basic structure of the tire.

[0004] The current technical solutions have limitations. Although they can improve the durability of tires to a certain extent, due to the lack of structural innovation, tires may still fail prematurely due to wear under certain specific conditions during actual use. Especially for semi-steel tires, how to reduce the heat generated by the tires during use while ensuring the hardness and rigidity of the tires has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a rubber compound for improving the durability of a semi-steel tire and a preparation method thereof. The application of this new rubber compound greatly improves the durability of the tire while maintaining good rigidity, thereby solving the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a rubber material for improving the durability of a semi-steel tire, the rubber material comprising the following components in parts by weight: 75-85 parts of natural rubber; 5-10 parts of butadiene-styrene rubber; 5-15 parts of rare earth butadiene rubber; 5-10 parts of zinc oxide; 1-2 parts of stearic acid; 30-40 parts of N330 carbon black; 30-40 parts of N660 carbon black; 4.5-6 parts of phenolic reinforcing resin; 1-2 parts of tert-butyl tackifying resin; 2-4 parts of antioxidant; 2-3.5 parts of accelerator; 3-5 parts of insoluble sulfur.

[0007] Preferably, the rubber material comprises the following components in parts by weight: 75 parts of natural rubber, 10 parts of butadiene-styrene rubber, 15 parts of rare earth butadiene rubber, 7 parts of zinc oxide, 1 part of stearic acid, 40 parts of N330 carbon black, 30 parts of N660 carbon black, 4.5 parts of phenolic reinforcing resin, 1.2 parts of tert-butyl tackifying resin, 2 parts of antioxidant, 2 parts of accelerator, and 4 parts of insoluble sulfur.

[0008] Preferably, the rubber material comprises the following components in parts by weight: 80 parts of natural rubber, 5 parts of butadiene-styrene rubber, 15 parts of rare earth butadiene rubber, 5 parts of zinc oxide, 1.5 parts of stearic acid, 35 parts of N330 carbon black, 35 parts of N660 carbon black, 5 parts of phenolic reinforcing resin, 1 part of tert-butyl tackifying resin, 3 parts of antioxidant, 2 parts of accelerator, and 3 parts of insoluble sulfur.

[0009] Preferably, the rubber material comprises the following components in parts by weight: 85 parts of natural rubber, 10 parts of butadiene-styrene rubber, 5 parts of rare earth butadiene rubber, 10 parts of zinc oxide, 2 parts of stearic acid, 30 parts of N330 carbon black, 40 parts of N660 carbon black, 6 parts of phenolic reinforcing resin, 2 parts of tert-butyl tackifying resin, 4 parts of antioxidant, 3.5 parts of accelerator, and 5 parts of insoluble sulfur.

[0010] In addition, the present invention provides a method for preparing a rubber material for improving the durability of a semi-steel tire, comprising the following steps:

[0011] Control the rotor speed of the internal mixer to 40-55rpm, the upper bolt pressure to 0.5-0.6MPa, and the cooling water temperature of the internal mixer to 25-35℃;

[0012] Add natural rubber, styrene-butadiene rubber, and rare earth butadiene rubber in sequence, press the top bolt and hold for 15-30 seconds;

[0013] Then raise the top plug and add zinc oxide, stearic acid, antioxidant, tackifying resin and carbon black, and press the top plug and hold for 15-25 seconds.

[0014] Preferably, the method further comprises the steps of: raising the top bolt and holding it for 5-10 seconds, pressing the top bolt to heat the rubber material to 135°C-145°C, then cleaning and pressing the top bolt again to heat the rubber material to 165°C for debinding, discharging the rubber material through a tablet press, and obtaining a masterbatch after cooling to room temperature.

[0015] Preferably, the method further comprises: mixing the first-stage masterbatch and the phenolic reinforcing resin at 140-150° C. for 85-105 seconds, and after the mixing is completed, unloading the rubber material to obtain the second-stage mixed rubber.

[0016] Preferably, the method further comprises: mixing the second-stage masterbatch with sulfur and an accelerator, controlling the temperature of the rubber material to 90-100° C., discharging the rubber material to an open mixing mill, and cooling the mixture to room temperature to obtain a final rubber mixture.

[0017] Technical effects and advantages of the present invention: Compared with the prior art, the rubber material for improving the durability of semi-steel tires and the preparation method thereof provided by the present invention have the following advantages:

[0018] The rubber compound proposed by the present invention has high hardness and low heat generation characteristics, and the Mooney viscosity of the rubber compound is effectively controlled by a multi-step mixing method, avoiding the frosting phenomenon that may occur in the extrusion process. By introducing rare earth butadiene rubber and two carbon blacks with different particle sizes, not only the fatigue resistance of the rubber compound is improved, but also the rubber compound is ensured to have a higher hardness and heat generation is reduced. Finally, the application of this new rubber compound greatly improves the durability of the tire while maintaining good rigidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 2 is a cross-sectional view of a tire in an embodiment of the present invention.

[0020] In the figure: 1. Sidewall rubber; 2. Rim wear-resistant rubber; 3. Rubber; 4. Tire carcass; 5. Apex rubber. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] In the present embodiment, a rubber material for improving the durability of a semi-steel tire is provided, and the rubber material includes the following components in parts by weight: 75 parts of natural rubber, 10 parts of butadiene-styrene rubber, 15 parts of rare earth butadiene rubber, 7 parts of zinc oxide, 1 part of stearic acid, 40 parts of N330 carbon black, 30 parts of N660 carbon black, 4.5 parts of phenolic reinforcing resin, 1.2 parts of tert-butyl tackifying resin, 2 parts of antioxidant, 2 parts of accelerator, and 4 parts of insoluble sulfur.

[0024] The preparation method of the rubber compound comprises the following steps:

[0025] Add natural rubber, styrene-butadiene rubber, and rare earth butadiene rubber to the internal mixer, control the rotor speed of the internal mixer to 40 rpm, the upper push pin pressure to 0.5 MPa, and the cooling water temperature to 25 ° C. Press the push pin and hold for 15 seconds to ensure that the raw materials are fully mixed.

[0026] After the top plug is raised, zinc oxide, stearic acid, antioxidant, tert-butyl tackifying resin, and N330 carbon black and N660 carbon black are added. The top plug is pressed and held for 15 seconds, and mixing is continued at the same speed during this stage.

[0027] The speed of the internal mixer was adjusted to 40 rpm, the top bolt was raised and held for 5 seconds, and then the top bolt was pressed to raise the temperature of the rubber compound to 135°C.

[0028] The top bolt is further raised to clean, and then the top bolt is pressed again to heat the rubber compound to 165°C, and then the rubber compound is discharged and produced through a tablet press, and a masterbatch is obtained after cooling to room temperature.

[0029] The first-stage masterbatch and the phenolic reinforcing resin were added to an internal mixer and mixed at 140° C. for 85 seconds. After the mixing was completed, the rubber was unloaded to obtain the second-stage mixed rubber.

[0030] Finally, the second-stage mixed rubber is added to the internal mixer, and sulfur and accelerator are added. When the temperature of the rubber compound rises to 90°C, the rubber compound is discharged to the open mixer, and the final rubber compound is obtained after being cooled to room temperature through the unloading operation.

[0031] The rubber compound prepared by the above steps has lower Mooney viscosity, higher hardness and good tensile strength, and is suitable for improving the durability of semi-steel tires.

[0032] Example 2

[0033] In the present embodiment, a rubber material for improving the durability of a semi-steel tire is provided, and the rubber material includes the following components in parts by weight: 80 parts of natural rubber, 5 parts of butadiene-styrene rubber, 15 parts of rare earth butadiene rubber, 5 parts of zinc oxide, 1.5 parts of stearic acid, 35 parts of N330 carbon black, 35 parts of N660 carbon black, 5 parts of phenolic reinforcing resin, 1 part of tert-butyl tackifying resin, 3 parts of antioxidant, 2 parts of accelerator, and 3 parts of insoluble sulfur.

[0034] The preparation method of the rubber compound comprises the following steps:

[0035] Add natural rubber, styrene-butadiene rubber and rare earth butadiene rubber into the internal mixer, control the rotor speed of the internal mixer to 50rpm, the upper push pin pressure to 0.55MPa, and the cooling water temperature to 30℃. Press the push pin and keep it for 20 seconds to ensure that the raw materials are fully mixed.

[0036] After the top plug is raised, zinc oxide, stearic acid, antioxidant, tert-butyl tackifying resin, and N330 carbon black and N660 carbon black are added. The top plug is pressed and held for 20 seconds, and mixing is continued at the same speed during this stage.

[0037] The speed of the internal mixer was adjusted to 40 rpm, the top bolt was raised and held for 7 seconds, and then the top bolt was pressed to raise the temperature of the rubber compound to 140°C.

[0038] The top bolt is further raised to clean, and then the top bolt is pressed again to heat the rubber compound to 165°C, and then the rubber compound is discharged and produced through a tablet press, and a masterbatch is obtained after cooling to room temperature.

[0039] The first-stage masterbatch and the phenolic reinforcing resin were added to an internal mixer and mixed at 130° C. for 100 seconds. After the mixing was completed, the rubber was unloaded to obtain the second-stage mixed rubber.

[0040] Finally, the second-stage mixed rubber is added to the internal mixer, and sulfur and accelerator are added. When the temperature of the rubber compound rises to 95°C, the rubber compound is discharged to the open mixer, and the final rubber compound is obtained after being cooled to room temperature through the unloading operation.

[0041] Example 3

[0042] In the present embodiment, a rubber material for improving the durability of a semi-steel tire is provided, and the rubber material includes the following components in parts by weight: 85 parts of natural rubber, 10 parts of butadiene-styrene rubber, 5 parts of rare earth butadiene rubber, 10 parts of zinc oxide, 2 parts of stearic acid, 30 parts of N330 carbon black, 40 parts of N660 carbon black, 6 parts of phenolic reinforcing resin, 2 parts of tert-butyl tackifying resin, 4 parts of antioxidant, 3.5 parts of accelerator, and 5 parts of insoluble sulfur.

[0043] In another embodiment, the above-mentioned butadiene-styrene rubber may be 0 parts; the rare earth butadiene rubber may be 0 parts.

[0044] The preparation method of the rubber compound comprises the following steps:

[0045] Add natural rubber, styrene-butadiene rubber and rare earth butadiene rubber into the internal mixer, control the rotor speed of the internal mixer to 55rpm, the upper push pin pressure to 0.6MPa, and the cooling water temperature to 35℃. Press the push pin and keep it for 30 seconds to ensure that the raw materials are fully mixed.

[0046] After the top plug is raised, zinc oxide, stearic acid, antioxidant, tert-butyl tackifying resin, and N330 carbon black and N660 carbon black are added. The top plug is pressed and held for 25 seconds, and mixing is continued at the same speed during this stage.

[0047] The speed of the internal mixer was adjusted to 40 rpm, the top bolt was raised and held for 10 seconds, and then the top bolt was pressed to raise the temperature of the rubber compound to 145°C.

[0048] The top bolt is further raised to clean, and then the top bolt is pressed again to heat the rubber compound to 165°C, and then the rubber compound is discharged and produced through a tablet press, and a masterbatch is obtained after cooling to room temperature.

[0049] The first-stage masterbatch and the phenolic reinforcing resin were added to an internal mixer and mixed at 150° C. for 105 seconds. After the mixing was completed, the rubber was unloaded to obtain the second-stage mixed rubber.

[0050] Finally, the second-stage mixed rubber is added to the internal mixer, and sulfur and accelerator are added. When the temperature of the rubber compound rises to 90-100°C, the rubber compound is discharged to the open mixer, and the final rubber compound is obtained after being cooled to room temperature through the unloading operation.

[0051] When implementing Examples 1-3, the components are as follows:

[0052] Example 1 (part) Example 2 (part) Example 3 (part) Natural Rubber 75 80 85 Butadiene-styrene rubber 10 5 10 Rare earth butadiene rubber 15 15 5 Zinc Oxide 7 5 10 Stearic acid 1 1.5 2 N330 Carbon Black 40 35 30 N660 Carbon Black 30 35 40 Phenolic Reinforced Resin 4.5 5 6 Tert-butyl tackifying resin 1.2 1 2 Antioxidant 2 3 4 Accelerator 2 2 3.5 Insoluble sulfur 4 3 5

[0053] The rubber compound prepared in the above embodiment is applied to a semi-steel tire, such as Figure 1 As shown, the rubber material 3 is located between the inner side of the sidewall rubber 1 and the rim wear-resistant rubber 2, and the outer side of the tire carcass 4 and the apex rubber 5; the rubber material has high hardness, low heat generation, and certain flexibility. Through the innovation of tire structure and the design of new rubber material formula, the processing technology is coordinated to improve the rigidity of the tire and achieve the purpose of improving the durability of the tire.

[0054] Taking Example 1 as an example, the physical and mechanical properties of the prepared product were tested, and the specific results are shown in the following table:

[0055] Physical and mechanical properties of the product

[0056] Test items Example 1 Mooney viscosity 50 Hardness(Shore A) 83 Tensile strength(MPa) 18.6 Elongation at break (%) 280 50% tensile stress (MPa) 3.3 100% modulus of tensile stress (MPa) 6.5

[0057] It can be seen from the physical and mechanical performance parameters in the above table that the rubber compound of the present invention has a low Mooney viscosity, a high hardness, a tensile strength of more than 18 MP, and excellent performance.

[0058] The 255 / 45R21 106Y XL tire prepared in Example 1 was subjected to a durability test, and the specific results are shown in the following table:

[0059] Tire durability test

[0060] Test items Example 1 Normal product Durability (≥44h) 135h 89h

[0061] It can be seen from the durability time in the above table that the durability of the rubber compound of the present invention is improved by more than 30% when used in tires.

[0062] Comparative Example 1

[0063] In order to prove the effectiveness of the rubber material for improving the durability of semi-steel tires and the preparation method thereof provided by the present invention, a comparative experiment can be conducted by setting up a comparative example.

[0064] Material ratio:

[0065] The composition of the rubber compound of the comparative example should be similar to that of the embodiment, but does not include the rare earth cis-1,2-butadiene rubber component, so as to observe its effect on the properties of the rubber compound. For example, the rubber compound of the comparative example may include the following components in parts by weight:

[0066] Natural rubber: 70 parts;

[0067] Butadiene-styrene rubber: 30 parts;

[0068] Zinc oxide: 4 parts;

[0069] Stearic acid: 1.5 parts;

[0070] N330 carbon black: 35 parts;

[0071] N660 carbon black: 25 parts;

[0072] Phenolic reinforcing resin: 3 parts;

[0073] Tert-butyl tackifying resin: 0.5 parts;

[0074] Anti-aging agent: 1 part;

[0075] Accelerator: 1.0 part;

[0076] Insoluble sulfur: 2.5 parts;

[0077] Preparation method:

[0078] The preparation method of the rubber compound of the comparative example should be consistent with that of the embodiment, except for the difference in the type or amount of the raw materials added. The specific steps are as follows:

[0079] Add natural rubber and styrene-butadiene rubber into the internal mixer, control the rotor speed of the internal mixer to 40rpm, the upper push pin pressure to 0.5MPa, and the cooling water temperature to 25℃. Press the push pin and keep it for 15 seconds to ensure that the raw materials are fully mixed.

[0080] After the top plug is raised, zinc oxide, stearic acid, antioxidant, tert-butyl tackifying resin, and N330 carbon black and N660 carbon black are added. The top plug is pressed and held for 15 seconds, and mixing is continued at the same speed during this stage.

[0081] The speed of the internal mixer was adjusted to 40 rpm, the top bolt was raised and held for 5 seconds, and then the top bolt was pressed to raise the temperature of the rubber compound to 135°C.

[0082] The top bolt is further raised to clean, and then the top bolt is pressed again to heat the rubber compound to 165°C, and then the rubber compound is discharged and produced through a tablet press, and a masterbatch is obtained after cooling to room temperature.

[0083] The first-stage masterbatch and the phenolic reinforcing resin were added to an internal mixer and mixed at 140° C. for 85 seconds. After the mixing was completed, the rubber was unloaded to obtain the second-stage mixed rubber.

[0084] Finally, the second-stage mixed rubber is added to the internal mixer, and sulfur and accelerator are added. When the temperature of the rubber compound rises to 90°C, the rubber compound is discharged to the open mixer, and the final rubber compound is obtained after being cooled to room temperature through the unloading operation.

[0085] The above-prepared rubber material is compared with the rubber material prepared in Example 1 of the present application. The following are specific performance test comparison data:

[0086] Test items Example 1 Comparative Example 1 Mooney viscosity 50 60 Hardness(Shore A) 83 70 Tensile strength(MPa) 18.6 17 Elongation at break (%) 280 230 50% tensile stress (MPa) 3.3 2.9 100% modulus of tensile stress (MPa) 6.5 4.2

[0087] It can be seen from the above table that the rubber compound of the present invention has a low Mooney viscosity, a high hardness, and a tensile strength of more than 18 MPa, showing excellent physical and mechanical properties.

[0088] The rubber compound prepared in Example 1 shows better physical and mechanical properties, such as lower Mooney viscosity, higher hardness, and tensile strength of more than 18MPa. In addition, the tire prepared in Example 1 performs better than conventional products in the durability test, indicating that the rubber compound of the present invention can indeed play a significant role in improving the durability of the tire. This is mainly due to the addition of rare earth butadiene rubber to the rubber compound formula of the present invention, and the use of a specific mixing process, so that the rubber compound has high hardness, low heat generation and good fatigue resistance. These improvements work together to greatly improve the durability of the tire while maintaining good rigidity.

[0089] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A rubber material for improving the durability of a semi-steel tire, characterized in that: The rubber material comprises the following components in parts by weight: Natural rubber 75-85 parts; Butadiene-styrene rubber 5-10 parts; 5-15 parts of rare earth butadiene rubber; Zinc oxide 5-10 parts; 1-2 parts of stearic acid; N330 carbon black 30-40 parts; N660 carbon black 30-40 parts; 4.5-6 parts of phenolic reinforcing resin; 1-2 parts of tert-butyl tackifying resin; 2-4 parts of antioxidant; 2-3.5 parts of accelerator; 3-5 parts of insoluble sulfur.

2. The rubber material for improving the durability of semi-steel tires according to claim 1, characterized in that: The rubber material comprises the following components in parts by weight: 75 parts of natural rubber, 10 parts of butadiene-styrene rubber, 15 parts of rare earth butadiene rubber, 7 parts of zinc oxide, 1 part of stearic acid, 40 parts of N330 carbon black, 30 parts of N660 carbon black, 4.5 parts of phenolic reinforcing resin, 1.2 parts of tert-butyl tackifying resin, 2 parts of antioxidant, 2 parts of accelerator and 4 parts of insoluble sulfur.

3. The rubber material for improving the durability of semi-steel tire according to claim 1, characterized in that: The rubber material comprises the following components in parts by weight: 80 parts of natural rubber, 5 parts of butadiene-styrene rubber, 15 parts of rare earth butadiene rubber, 5 parts of zinc oxide, 1.5 parts of stearic acid, 35 parts of N330 carbon black, 35 parts of N660 carbon black, 5 parts of phenolic reinforcing resin, 1 part of tert-butyl tackifying resin, 3 parts of antioxidant, 2 parts of accelerator and 3 parts of insoluble sulfur.

4. The rubber material for improving the durability of semi-steel tire according to claim 1, characterized in that: The rubber material comprises the following components in parts by weight: 85 parts of natural rubber, 10 parts of butadiene-styrene rubber, 5 parts of rare earth butadiene rubber, 10 parts of zinc oxide, 2 parts of stearic acid, 30 parts of N330 carbon black, 40 parts of N660 carbon black, 6 parts of phenolic reinforcing resin, 2 parts of tert-butyl tackifying resin, 4 parts of antioxidant, 3.5 parts of accelerator and 5 parts of insoluble sulfur.

5. A method for preparing the rubber compound according to any one of claims 1 to 4, characterized in that: The steps include: Control the rotor speed of the internal mixer to 40-55rpm, the upper bolt pressure to 0.5-0.6MPa, and the cooling water temperature of the internal mixer to 25-35℃; Add natural rubber, styrene-butadiene rubber, and rare earth butadiene rubber in sequence, press the top bolt and hold for 15-30 seconds; Then raise the top plug and add zinc oxide, stearic acid, antioxidant, tackifying resin and carbon black, and press the top plug and hold for 15-25 seconds.

6. The method according to claim 5, characterized in that Also includes the steps: Raise the top plug and hold for 5-10 seconds, press the top plug to raise the temperature of the rubber to 135℃-145℃, then clean it and press the top plug again to raise the temperature of the rubber to 165℃ for discharge, and then discharge the rubber through the tablet press. After cooling to room temperature, a masterbatch is obtained.

7. The method according to claim 6, characterized in that Also includes: The first-stage masterbatch and the phenolic reinforcing resin are mixed at 140-150° C. for 85-105 seconds. After the mixing is completed, the rubber material is unloaded to obtain the second-stage mixed rubber.

8. The method according to claim 7, characterized in that Also includes: The second-stage masterbatch is mixed with sulfur and accelerator, the temperature of the rubber is controlled to 90-100°C, the rubber is discharged to the mixing mill, and the final rubber is obtained after cooling to room temperature.

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