Rare earth rubber vulcanizing agent capable of prolonging service life of tire and production method of rare earth rubber vulcanizing agent

Abstract

The invention discloses a rare earth rubber vulcanizing agent capable of prolonging the service life of a tire and a production method of the rare earth rubber vulcanizing agent, and belongs to the technical field of range, and in the rare earth rubber vulcanizing agent, a cross-linked network structure of rubber is remarkably optimized by introducing a synergistic vulcanization system of rare earth element lanthanum oxide and sulfur. The nanoscale dispersion of lanthanum oxide and the pre-compounding treatment of white carbon black enhance the interface bonding force between the filler and the rubber matrix, so that the vulcanization reaction is more uniform and efficient. And compared with the traditional formula, the vulcanization time is shortened, and the crosslinking density is greatly improved, so that the heat generation effect during dynamic use of the tire is greatly reduced. Meanwhile, a compound filling system of the nano white carbon black and the carbon black is assisted by the silane coupling agent, so that the balance between low rolling resistance and high wear resistance is realized, the DIN wear value of the tread rubber is reduced, the tear strength is improved, and the service life of the tire under complex road conditions is directly prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of tire production, and specifically relates to a rare earth rubber vulcanizing agent for extending the service life of tires and a production method thereof. Background Art

[0002] Rubber vulcanizing agents are indispensable important chemical auxiliaries in the rubber industry. Their main function is to form a stable three-dimensional network structure of rubber molecular chains through chemical cross-linking, thereby endowing rubber products with good physical and mechanical properties and durability. Common vulcanizing agents include sulfur, peroxides, quinone compounds, etc. They play their respective advantages in different vulcanization systems to meet the needs of different rubber products. The selection and use of vulcanizing agents directly affect the performance of rubber products, such as hardness, elasticity, heat resistance, aging resistance, etc. Therefore, the research and application of rubber vulcanizing agents have always been the key areas of technological innovation in the rubber industry, aiming to improve product quality, reduce costs and meet increasingly stringent environmental and safety requirements.

[0003] However, the traditional vulcanization system overly relies on sulfur, resulting in low vulcanization efficiency, loose cross-linking network, high dynamic heat generation of tires and insufficient wear resistance; at the same time, petroleum-based plasticizers and single anti-aging agents are prone to cause environmental pollution and have limited anti-aging performance, and cannot take into account the protection against thermal oxygen and ozone aging. Summary of the Invention

[0004] The purpose of the present invention is to provide a rare earth rubber vulcanizing agent for extending the service life of tires and a production method thereof in order to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: A rare earth rubber vulcanizing agent for extending the service life of tires, the vulcanizing agent comprising: 70 parts by weight of natural rubber, 30 parts by weight of styrene-butadiene rubber, 3-5 parts by weight of lanthanum oxide, 1.5 parts by weight of sulfur, 40 parts by weight of nano-silica, 20 parts by weight of carbon black, 2 parts by weight of silane coupling agent Si69, 2 parts by weight of anti-aging agent, 1 part by weight of microcrystalline wax, 3 parts by weight of zinc oxide, 1 part by weight of stearic acid, and 5 parts by weight of vegetable oil-based plasticizer.

[0006] In a preferred embodiment, the production method comprises the following steps:

[0007] S1: Mix lanthanum oxide and nano-silica in proportion, add them to a ball mill for dry grinding for 2 hours, and the ball mill rotation speed is 300 rpm, so that the particle size of lanthanum oxide is reduced to 50 to 100 nanometers and a pre-dispersed complex is formed with silica;

[0008] S2: Put natural rubber and styrene-butadiene rubber into an internal mixer, set the temperature of the internal mixer to 80 to 90 degrees Celsius, and sequentially add stearic acid, zinc oxide and vegetable oil-based plasticizer, and knead for 3 minutes until the rubber compound is uniformly plasticized;

[0009] S3: Add the pretreated lanthanum oxide and silica complex, carbon black, and silane coupling agent Si69 into the internal mixer, control the mixing temperature not exceeding 120 °C, and mix for 6 minutes until the fillers are completely dispersed;

[0010] S4: Add sulfur, antioxidant 4020, and microcrystalline wax, lower the mixing temperature to 70 - 80 °C, and continue mixing for 2 minutes to prevent premature reaction of sulfur.

[0011] S5: Transfer the mixed rubber compound to the open mill and thin - pass it 3 times. Keep the roll temperature of the open mill at 50 °C. After sheeting, place it in an environment of 25 °C and let it stand for 24 hours.

[0012] S6: Preheat the standing rubber compound to 60 °C, and form it into tire components through an extruder or calender, controlling the thickness tolerance within the range of plus or minus 0.1 mm.

[0013] S7: Put the formed rubber compound into a vulcanization mold and conduct two - stage vulcanization:

[0014] The temperature of the first - stage vulcanization is 150 °C, the pressure is 15 MPa, and the vulcanization time is determined according to T90 measured by a rheometer, usually 80% of the vulcanization time of the traditional formula;

[0015] The temperature of the second - stage vulcanization is 120 °C, and vulcanize under normal pressure for 2 hours to stabilize the cross - linked network.

[0016] S8: After vulcanization, the tire components are trimmed and cooled to room temperature. Optionally, spray an anti - ozone wax coating to enhance surface protection.

[0017] S9: Conduct wear resistance tests, dynamic heat generation tests, and thermal - oxidative aging tests on the finished products. The detection standards are the DIN abrasion method, Goodrich flexing test, and thermal - oxidative aging at 70 °C for 72 hours respectively. After passing the tests, store them in the warehouse.

[0018] In a preferred embodiment, in the step S1, after mixing lanthanum oxide and nano - silica according to the formula ratio, put them into a planetary ball mill for dry grinding treatment. Set the rotation speed of the ball mill at 300 revolutions per minute, the grinding time at 2 hours, use zirconia ceramic balls as the grinding medium, and the ball - to - material ratio at 10:1. Strictly control the temperature not exceeding 50 °C during the grinding process, and prevent the material from overheating through intermittent cooling. The ground mixed material needs to be detected by a laser particle size analyzer to ensure that the particle size distribution of lanthanum oxide is in the range of 50 - 100 nm and forms a uniform pre - dispersed complex with silica. The key to this step is to achieve nano - scale dispersion of rare - earth particles and avoid agglomeration during subsequent mixing.

[0019] In a preferred embodiment, in step S2, natural rubber and styrene-butadiene rubber are put into a Banbury mixer. The initial temperature of the Banbury mixer is set at 80 °C, and the rotor speed is adjusted to 60 revolutions per minute. Stearic acid, zinc oxide, and a vegetable oil-based plasticizer are added in sequence, with a feeding interval of 30 seconds to ensure uniform mixing. During the mixing process, the temperature of the Banbury mixer gradually rises, and the temperature needs to be controlled below 90 °C through a circulating water cooling system. The total mixing time is 3 minutes. The final rubber compound should present a plasticized state without granularity and with a smooth surface, and its Mooney viscosity is detected by a Haake rheometer to ensure that it reaches the standard range of 45±5 ML(1+4, 100 °C).

[0020] In a preferred embodiment, in step S3, after the temperature of the Banbury mixer drops to 100 °C, a pretreated lanthanum oxide and silica complex, carbon black N330, and a silane coupling agent Si69 are added. The rotor speed of the Banbury mixer is increased to 80 revolutions per minute, and the mixing temperature is strictly limited within 120 °C through a PID control system. The mixing time is 6 minutes. During this period, the dispersion state of the filler is monitored through a torque change curve. When the torque is stable within a ±5% fluctuation range, it is considered that the dispersion is complete. In this stage, it is necessary to avoid premature hydrolysis and failure of the silane coupling agent due to excessive temperature. The cross-section of the final rubber compound should show uniform distribution of the filler without aggregation under an electron microscope.

[0021] In a preferred embodiment, in step S4, the temperature of the Banbury mixer is adjusted to 70 °C, and the rotor speed is reduced to 40 revolutions per minute. Sulfur, antioxidant 4020, and microcrystalline wax are added in sequence. The mixing time is 2 minutes, and the temperature during the process shall not exceed 80 °C to prevent premature cross-linking reaction caused by sulfur. After the feeding is completed, the vulcanization characteristics of the rubber compound are tested by rapid sampling. The scorch time (T10) measured by a rotorless vulcanizer should be greater than 5 minutes to ensure processing safety. The rubber compound in this stage should present a low viscoelastic state for subsequent molding operations.

[0022] In a preferred embodiment, in step S5, the mixed rubber compound is discharged from the bottom plug of the Banbury mixer to a two-roll mill. The temperature of the roll is set at 50 °C, and the roll gap is adjusted to 1 mm for three passes of thin-sheeting. After thin-sheeting, the thickness of the rubber compound sheet is controlled at 2.5±0.2 mm, and then it is transferred to a constant temperature and humidity chamber and left standing for 24 hours in an environment of 25 °C and 50% relative humidity. During the standing process, the internal stress of the rubber compound is gradually released, and the fluctuation of its storage modulus detected by a dynamic thermomechanical analyzer needs to be less than 5% to ensure material stability.

[0023] In a preferred embodiment, in step S6, the static rubber compound is preheated to 60°C in a hot air circulation oven and maintained for 20 minutes, and then formed by a Φ120mm cold feed extruder or a three-roll calender. The screw speed of the extruder is set at 30 revolutions per minute, the die temperature is controlled at 70°C, and the thickness tolerance of the formed tread rubber is ±0.1 mm. The roll temperature gradient of the calender is set at 60°C for the lower roll, 65°C for the middle roll, and 70°C for the upper roll to ensure the fluidity and dimensional accuracy of the rubber compound.

[0024] In a preferred embodiment, in step S7, the formed rubber compound is loaded into a preheated tire vulcanization mold, and two-stage vulcanization is carried out using an electric heating flat vulcanizer. The conditions for the first-stage vulcanization are a temperature of 150°C, a pressure of 15 MPa, and the vulcanization time is determined according to the optimum vulcanization time T90 measured by a rheometer, usually 80% of the traditional sulfur vulcanization time (for example, if the original T90 is 10 minutes, it is shortened to 8 minutes). The second-stage vulcanization is carried out in a hot air aging oven at a temperature of 120°C and normal pressure for 2 hours. The change in crosslink density is monitored by a differential scanning calorimeter to ensure that the crosslinking degree increases by more than 15% after the secondary vulcanization.

[0025] In a preferred embodiment, in step S8, the vulcanized tire parts are trimmed to remove flash by a water cutting machine, and then the temperature is reduced from 120°C to room temperature within 15 minutes by a spray cooling system. The surface treatment is carried out using a high-pressure airless spraying device, and an anti-ozone wax coating with a thickness of 10 to 15 microns is sprayed. The spraying pressure is set at 20 MPa, the nozzle diameter is 0.5 mm, and it needs to be dried in a 40°C drying oven for 10 minutes after spraying to form a continuous protective film.

[0026] In step S9, the finished tire parts are subjected to full-item inspection according to ISO standards: the abrasion resistance is tested using a DIN abrasion tester (load 10 N, sandpaper grit 60), and the abrasion volume should be less than 120 cubic millimeters; the dynamic heat generation is measured by a Goodrich flexometer (frequency 30 Hz, strain rate 25%), and the temperature rise should not exceed 30°C; the thermo-oxidative aging test is carried out in an oven at 70°C for 72 hours, and the retention rate of the tensile strength after aging should be greater than 85%. After all the indicators meet the standards, before the product is warehoused, X-ray flaw detection and dynamic balance detection are required to ensure no internal defects and quality consistency.

[0027] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0028] 1. In the present invention, by introducing a synergistic vulcanization system of rare earth element lanthanum oxide and sulfur, the crosslinked network structure of rubber is significantly optimized. The nano-scale dispersion of lanthanum oxide and its pre-compounding treatment with silica enhance the interfacial bonding force between the filler and the rubber matrix, making the vulcanization reaction more uniform and efficient. Compared with the traditional formula, the vulcanization time is shortened, and the crosslinking density is greatly increased, thus significantly reducing the heat generation effect during the dynamic use of the tire. At the same time, the compound filling system of nano-silica and carbon black, with the assistance of a silane coupling agent, achieves a balance between low rolling resistance and high wear resistance. The DIN abrasion value of the tread rubber decreases, and the tear resistance strength increases, directly extending the service life of the tire under complex road conditions.

[0029] 2. In the present invention, using a vegetable oil-based plasticizer to replace the traditional petroleum-based plasticizer not only reduces the dependence on non-renewable resources but also reduces the emission of volatile organic compounds during the production process, meeting the environmental protection standards of green tires. The composite anti-aging system of anti-aging agent and microcrystalline wax effectively inhibits thermal-oxidative aging and ozone cracking through dual mechanisms of chemical blocking and physical shielding. After 72 hours of thermal-oxidative aging at 70 degrees Celsius, the tensile strength retention rate of the rubber compound exceeds 85%, far exceeding 70% of the conventional formula. In addition, the two-stage vulcanization process reduces the risk of over-vulcanization while ensuring the stability of the crosslinked network, increasing the comprehensive durability of the finished tire by more than 30% and taking into account the requirements of energy conservation and long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the process principle of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Example 1:

[0033] Referring to Figure 1 , a rare earth rubber vulcanizing agent for extending the service life of a tire, the vulcanizing agent includes: 70 parts by weight of natural rubber, 30 parts by weight of styrene-butadiene rubber, 3 parts by weight of lanthanum oxide, 1.5 parts by weight of sulfur, 40 parts by weight of nano-silica, 20 parts by weight of carbon black, 2 parts by weight of silane coupling agent Si69, 2 parts by weight of anti-aging agent, 1 part by weight of microcrystalline wax, 3 parts by weight of zinc oxide, 1 part by weight of stearic acid, and 5 parts by weight of vegetable oil-based plasticizer.

[0034] The production method includes the following steps:

[0035] S1: Mix lanthanum oxide and nano - silica in proportion, add them to a ball mill for dry grinding for 2 hours at a ball - mill rotation speed of 300 rpm to reduce the particle size of lanthanum oxide to 50 - 100 nanometers and form a pre - dispersed complex with silica;

[0036] S2: Put natural rubber and styrene - butadiene rubber into an internal mixer, set the temperature of the internal mixer at 80 - 90 °C, and sequentially add stearic acid, zinc oxide, and vegetable - oil - based plasticizer, and knead for 3 minutes until the rubber compound is evenly plasticized;

[0037] S3: Add the pretreated lanthanum oxide and silica complex, carbon black, and silane coupling agent Si69 to the internal mixer, control the kneading temperature not to exceed 120 °C, and knead for 6 minutes until the fillers are completely dispersed;

[0038] S4: Add sulfur, antioxidant 4020, and microcrystalline wax, lower the kneading temperature to 70 - 80 °C, and continue kneading for 2 minutes to prevent premature reaction of sulfur.

[0039] S5: Transfer the kneaded rubber compound to a two - roll mill for three passes of thin - passing. Keep the roll temperature of the two - roll mill at 50 °C. After sheeting, place it in an environment at 25 °C and let it stand for 24 hours.

[0040] S6: Preheat the standing rubber compound to 60 °C, and form it into tire components through an extruder or calender, controlling the thickness tolerance within the range of ±0.1 mm.

[0041] S7: Put the formed rubber compound into a vulcanization mold for two - stage vulcanization:

[0042] The temperature of the first - stage vulcanization is 150 °C, the pressure is 15 MPa, and the vulcanization time is determined according to T90 measured by a rheometer, usually 80% of the vulcanization time of the traditional formula;

[0043] The temperature of the second - stage vulcanization is 120 °C, and vulcanize under normal pressure for 2 hours to stabilize the cross - linked network.

[0044] S8: After vulcanization, the tire components are trimmed and cooled to room temperature. Optionally, spray an anti - ozone wax coating to enhance surface protection.

[0045] S9: Conduct wear resistance tests, dynamic heat - generation tests, and thermal - oxidative aging tests on the finished products. The detection standards are the DIN abrasion method, Goodrich flexing test, and thermal - oxidative aging at 70 °C for 72 hours respectively. After passing the tests, store them in the warehouse.

[0046] In step S1, after mixing lanthanum oxide and nano - silica according to the formula ratio, they are put into a planetary ball mill for dry grinding. The rotational speed of the ball mill is set at 300 revolutions per minute, the grinding time is 2 hours, the grinding medium is zirconia ceramic balls, and the ball - to - material ratio is 10:1. During the grinding process, the temperature is strictly controlled not to exceed 50 degrees Celsius, and intermittent cooling is used to prevent the material from overheating. The ground mixture needs to be detected by a laser particle size analyzer to ensure that the particle size of lanthanum oxide is distributed in the range of 50 to 100 nanometers and forms a uniform pre - dispersed complex with silica. The key to this step is to achieve nano - scale dispersion of rare - earth particles and avoid agglomeration during subsequent mixing.

[0047] In step S2, natural rubber and styrene - butadiene rubber are put into an internal mixer. The initial temperature of the internal mixer is set at 80 degrees Celsius, and the rotor speed is adjusted to 60 revolutions per minute. Stearic acid, zinc oxide, and a vegetable - oil - based plasticizer are added in sequence, with a feeding interval of 30 seconds to ensure uniform mixing. During the mixing process, the temperature of the internal mixer gradually rises, and the temperature needs to be controlled below 90 degrees Celsius through a circulating water cooling system. The total mixing time is 3 minutes, and the final rubber compound should show a plasticized state without particle sense and a smooth surface, and its Mooney viscosity is detected by a Hake rheometer to ensure it reaches the standard range of 45±5 ML(1 + 4, 100℃).

[0048] In step S3, after the temperature of the internal mixer drops to 100 degrees Celsius, the pretreated lanthanum oxide and silica complex, carbon black N330, and silane coupling agent Si69 are added. The rotor speed of the internal mixer is increased to 80 revolutions per minute, and the mixing temperature is strictly limited within 120 degrees Celsius through a PID control system. The mixing time is 6 minutes. During this period, the dispersion state of the filler is monitored through the torque change curve. When the torque is stable within a ±5% fluctuation range, it is considered that the dispersion is complete. In this stage, it is necessary to avoid premature hydrolysis and inactivation of the silane coupling agent due to excessive temperature. The cross - section of the final rubber compound should show uniform distribution of the filler without aggregation under an electron microscope.

[0049] In step S4, the temperature of the internal mixer is adjusted to 70 degrees Celsius, the rotor speed is reduced to 40 revolutions per minute, and sulfur, antioxidant 4020, and microcrystalline wax are added in sequence. The mixing time is 2 minutes, and the temperature during the process shall not exceed 80 degrees Celsius to prevent premature cross - linking reaction of sulfur. After the feeding is completed, the vulcanization characteristics of the rubber compound are tested by rapid sampling of the rubber compound. The scorch time (T10) measured by a non - rotating rotor vulcanizer should be greater than 5 minutes to ensure processing safety. The rubber compound in this stage needs to show a low visco - elastic state for subsequent molding operations.

[0050] In step S5, the kneaded rubber compound is discharged from the bottom plug of the internal mixer to a two-roll mill. The roller temperature is set at 50 °C, and the roll gap is adjusted to 1 mm for three passes of thin-sheeting. After thin-sheeting, the thickness of the rubber compound sheet is controlled at 2.5 ± 0.2 mm, and then it is transferred to a constant temperature and humidity chamber and left standing for 24 hours in an environment of 25 °C and 50% relative humidity. During the standing process, the internal stress of the rubber compound is gradually released, and the fluctuation of its storage modulus detected by a dynamic thermomechanical analyzer should be less than 5% to ensure material stability.

[0051] In step S6, the standing rubber compound is preheated to 60 °C in a hot air circulation oven and maintained for 20 minutes, and then it is formed by a Φ120mm cold-feed extruder or a three-roll calender. The screw speed of the extruder is set at 30 revolutions per minute, the die temperature is controlled at 70 °C, and the thickness tolerance of the formed tread rubber is ±0.1 mm. The roll temperature gradient of the calender is set at 60 °C for the lower roll, 65 °C for the middle roll, and 70 °C for the upper roll to ensure the fluidity and dimensional accuracy of the rubber compound.

[0052] In step S7, the formed rubber compound is loaded into a preheated tire vulcanization mold, and two-stage vulcanization is carried out using an electric heating flat vulcanizer. The conditions for the first-stage vulcanization are a temperature of 150 °C, a pressure of 15 MPa, and the vulcanization time is determined according to the optimum vulcanization time T90 measured by a rheometer, usually 80% of the traditional sulfur vulcanization time (for example, if the original T90 is 10 minutes, it is shortened to 8 minutes). The second-stage vulcanization is carried out in a hot air aging chamber at a temperature of 120 °C and atmospheric pressure for 2 hours, and the change in crosslink density is monitored by a differential scanning calorimeter to ensure that the crosslinking degree increases by more than 15% after the secondary vulcanization.

[0053] In step S8, the vulcanized tire component is trimmed to remove flash by a water jet cutter, and then the temperature is reduced from 120 °C to room temperature within 15 minutes through a spray cooling system. The surface treatment uses a high-pressure airless spraying device to spray an anti-ozone wax coating with a thickness of 10 to 15 microns. The spraying pressure is set at 20 MPa, the nozzle diameter is 0.5 mm, and it needs to be dried in a 40 °C drying oven for 10 minutes after spraying to form a continuous protective film.

[0054] In step S9, the finished tire component is subjected to full-item inspection according to ISO standards: the abrasion resistance is tested using a DIN abrasion tester (load 10 N, sandpaper grit 60 mesh), and the abrasion volume should be less than 120 cubic millimeters; the dynamic heat generation is measured by a Goodrich flexometer (frequency 30 Hz, strain rate 25%), and the temperature rise should not exceed 30 °C; the thermo-oxidative aging test is carried out in an oven at 70 °C for 72 hours, and the retention rate of the tensile strength after aging should be greater than 85%. After all indicators meet the standards, before the product is warehoused, X-ray flaw detection and dynamic balance detection are required to ensure no internal defects and quality consistency.

[0055] It can be known from the above that:

[0056] In the present invention, by introducing a synergistic vulcanization system of rare earth element lanthanum oxide and sulfur, the crosslinked network structure of rubber is significantly optimized. The nanoscale dispersion of lanthanum oxide and the pre-compounding treatment with silica enhance the interfacial bonding force between the filler and the rubber matrix, making the vulcanization reaction more uniform and efficient. Compared with the traditional formulation, the vulcanization time is shortened and the crosslink density is greatly increased, thus significantly reducing the heat generation effect during the dynamic use of the tire. At the same time, the compound filling system of nano-silica and carbon black, with the assistance of a silane coupling agent, achieves a balance between low rolling resistance and high wear resistance. The DIN abrasion value of the tread rubber decreases and the tear resistance strength increases, directly extending the service life of the tire under complex road conditions.

[0057] In the present invention, using a vegetable oil-based plasticizer to replace the traditional petroleum-based plasticizer not only reduces the dependence on non-renewable resources but also reduces the emission of volatile organic compounds during the production process, meeting the environmental protection standards of green tires. The composite anti-aging system of anti-aging agent and microcrystalline wax effectively inhibits thermal-oxidative aging and ozone cracking through dual mechanisms of chemical blocking and physical shielding. After 72 hours of thermal-oxidative aging at 70 degrees Celsius, the tensile strength retention rate of the rubber compound exceeds 85%, far exceeding 70% of the conventional formulation. In addition, the two-stage vulcanization process reduces the risk of over-vulcanization while ensuring the stability of the crosslinked network, increasing the comprehensive durability of the finished tire by more than 30% and taking into account the requirements of energy conservation and long-term use.

[0058] Example Two:

[0059] Refer to Figure 1 , a rare earth rubber vulcanizing agent for extending the service life of a tire, the vulcanizing agent comprising: 70 parts by weight of natural rubber, 30 parts by weight of styrene-butadiene rubber, 5 parts by weight of lanthanum oxide, 1.5 parts by weight of sulfur, 40 parts by weight of nano-silica, 20 parts by weight of carbon black, 2 parts by weight of silane coupling agent Si69, 2 parts by weight of anti-aging agent, 1 part by weight of microcrystalline wax, 3 parts by weight of zinc oxide, 1 part by weight of stearic acid, and 5 parts by weight of vegetable oil-based plasticizer.

[0060] The production method comprises the following steps:

[0061] S1: Mix lanthanum oxide and nano-silica in proportion, add them to a ball mill for dry grinding for 2 hours, with the ball mill rotation speed being 300 rpm, reducing the particle size of lanthanum oxide to 50 to 100 nanometers and forming a pre-dispersed complex with silica.

[0062] S2: Feed natural rubber and styrene-butadiene rubber into an internal mixer, set the temperature of the internal mixer to 80 to 90 degrees Celsius, and sequentially add stearic acid, zinc oxide, and vegetable oil-based plasticizer, and knead for 3 minutes until the rubber compound is uniformly plasticized.

[0063] S3: Add the pre-treated lanthanum oxide and silica complex, carbon black, and silane coupling agent Si69 into the internal mixer, control the mixing temperature not to exceed 120 °C, and mix for 6 minutes until the fillers are completely dispersed;

[0064] S4: Add sulfur, antioxidant 4020, and microcrystalline wax, lower the mixing temperature to 70 - 80 °C, and continue mixing for 2 minutes to prevent premature reaction of sulfur.

[0065] S5: Transfer the mixed rubber compound to the open mill and thin pass it 3 times. Keep the roll temperature of the open mill at 50 °C. After sheeting, place it in an environment of 25 °C and let it stand for 24 hours.

[0066] S6: Preheat the standing rubber compound to 60 °C, and form it into tire components through an extruder or calender, controlling the thickness tolerance within the range of plus or minus 0.1 mm.

[0067] S7: Put the formed rubber compound into a vulcanization mold and conduct two-stage vulcanization:

[0068] For the first-stage vulcanization, the temperature is 150 °C, the pressure is 15 MPa, and the vulcanization time is determined according to T90 measured by a rheometer, usually 80% of the vulcanization time of the traditional formula;

[0069] For the second-stage vulcanization, the temperature is 120 °C, and vulcanize under normal pressure for 2 hours to stabilize the crosslinked network.

[0070] S8: After vulcanization, the tire components are trimmed and cooled to room temperature. Optionally, spray an anti-ozone wax coating to enhance surface protection.

[0071] S9: Conduct wear resistance test, dynamic heat generation test, and thermal-oxidative aging test on the finished product. The detection standards are DIN abrasion method, Goodrich flexing test, and thermal-oxidative aging at 70 °C for 72 hours respectively. After passing the tests, store them in the warehouse.

[0072] In step S1, after mixing lanthanum oxide and nano-silica according to the formula ratio, put them into a planetary ball mill for dry grinding treatment. Set the rotation speed of the ball mill at 300 revolutions per minute, the grinding time at 2 hours, use zirconia ceramic balls as the grinding medium, and the ball-to-material ratio at 10:1. Strictly control the temperature not to exceed 50 °C during the grinding process, and prevent the material from overheating through intermittent cooling. The mixed material after grinding needs to be detected by a laser particle size analyzer to ensure that the particle size distribution of lanthanum oxide is within the range of 50 - 100 nm and forms a uniform pre-dispersed complex with silica. The key to this step is to achieve nano-scale dispersion of rare earth particles and avoid agglomeration during subsequent mixing.

[0073] In step S2, natural rubber and styrene-butadiene rubber are put into a Banbury mixer. The initial temperature of the Banbury mixer is set at 80 °C, and the rotor speed is adjusted to 60 revolutions per minute. Stearic acid, zinc oxide, and vegetable oil-based plasticizer are added sequentially, with a feeding interval of 30 seconds to ensure uniform mixing. During the mixing process, the temperature of the Banbury mixer gradually rises, and the temperature needs to be controlled below 90 °C through a circulating water cooling system. The total mixing time is 3 minutes. The final rubber compound should exhibit a plasticized state without granules and a smooth surface, and its Mooney viscosity is detected by a Haake rheometer to ensure it reaches the standard range of 45±5 ML(1+4, 100 °C).

[0074] In step S3, after the temperature of the Banbury mixer drops to 100 °C, the pretreated lanthanum oxide and silica complex, carbon black N330, and silane coupling agent Si69 are added. The rotor speed of the Banbury mixer is increased to 80 revolutions per minute, and the mixing temperature is strictly limited within 120 °C through a PID control system. The mixing time is 6 minutes. During this period, the filler dispersion state is monitored through the torque change curve. When the torque stabilizes within a ±5% fluctuation range, it is considered that the dispersion is complete. In this stage, it is necessary to avoid premature hydrolysis and failure of the silane coupling agent due to excessive temperature. The cross-section of the final rubber compound should show uniform distribution of the filler without aggregation under an electron microscope.

[0075] In step S4, the temperature of the Banbury mixer is adjusted to 70 °C, and the rotor speed is reduced to 40 revolutions per minute. Sulfur, antioxidant 4020, and microcrystalline wax are added sequentially. The mixing time is 2 minutes, and the temperature during the process should not exceed 80 °C to prevent premature cross-linking reaction of sulfur. After the feeding is completed, the vulcanization characteristics of the rubber compound are tested by rapid sampling of the rubber compound. The scorch time (T10) measured by a rotorless vulcanizer should be greater than 5 minutes to ensure processing safety. The rubber compound in this stage needs to exhibit a low viscoelastic state for subsequent molding operations.

[0076] In step S5, the mixed rubber compound is discharged from the bottom plug of the Banbury mixer to a two-roll mill. The temperature of the roll is set at 50 °C, and the roll gap is adjusted to 1 mm for three passes of thin-sheeting. After thin-sheeting, the thickness of the rubber compound sheet is controlled at 2.5±0.2 mm, and then it is transferred to a constant temperature and humidity chamber and left standing for 24 hours in an environment of 25 °C and 50% relative humidity. During the standing process, the internal stress of the rubber compound is gradually released, and the fluctuation of its storage modulus detected by a dynamic thermomechanical analyzer needs to be less than 5% to ensure material stability.

[0077] In step S6, the static rubber compound is preheated to 60 °C in a hot air circulation oven and maintained for 20 minutes, and then formed by a Φ120 mm cold feed extruder or a three-roll calender. The screw speed of the extruder is set at 30 revolutions per minute, the die temperature is controlled at 70 °C, and the thickness tolerance of the formed tread rubber is ±0.1 mm. The roll temperature gradient of the calender is set at 60 °C for the lower roll, 65 °C for the middle roll, and 70 °C for the upper roll to ensure the fluidity and dimensional accuracy of the rubber compound.

[0078] In step S7, the formed rubber compound is loaded into a preheated tire vulcanization mold, and two-stage vulcanization is carried out using an electric heating flat vulcanizer. The conditions for the first-stage vulcanization are a temperature of 150 °C, a pressure of 15 MPa, and the vulcanization time is determined according to the optimum vulcanization time T90 measured by a rheometer, usually 80% of the traditional sulfur vulcanization time (for example, if the original T90 is 10 minutes, it is shortened to 8 minutes). The second-stage vulcanization is carried out in a hot air aging oven at a temperature of 120 °C and normal pressure for 2 hours. The change in crosslink density is monitored by a differential scanning calorimeter to ensure that the crosslinking degree increases by more than 15% after the secondary vulcanization.

[0079] In step S8, the vulcanized tire parts are trimmed by a water cutting machine to remove flash, and then the temperature is reduced from 120 °C to room temperature within 15 minutes through a spray cooling system. The surface treatment uses a high-pressure airless spraying device to spray an anti-ozone wax coating with a thickness of 10 to 15 microns. The spraying pressure is set at 20 MPa, the nozzle diameter is 0.5 mm, and it needs to be dried in a 40 °C drying oven for 10 minutes after spraying to form a continuous protective film.

[0080] In step S9, the finished tire parts are subjected to full-item inspection according to ISO standards: the abrasion resistance is tested using a DIN abrasion tester (load 10 N, sandpaper grit 60), and the abrasion volume should be less than 120 cubic millimeters; the dynamic heat generation is measured by a Goodrich flexometer (frequency 30 Hz, strain rate 25%), and the temperature rise should not exceed 30 °C; the thermal oxygen aging test is carried out in an oven at 70 °C for 72 hours, and the tensile strength retention rate after aging should be greater than 85%. After all indicators meet the standards, X-ray flaw detection and dynamic balance detection are required before the product is warehoused to ensure no internal defects and quality consistency.

[0081] It can be seen from the above:

[0082] In the present invention, by introducing a synergistic vulcanization system of rare earth element lanthanum oxide and sulfur, the crosslinking network structure of the rubber is significantly optimized. The nano-scale dispersion of lanthanum oxide and the pre-compounding treatment with silica enhance the interfacial bonding force between the filler and the rubber matrix, making the vulcanization reaction more uniform and efficient. Compared with the traditional formulation, the vulcanization time is shortened and the crosslinking density is greatly increased, thus significantly reducing the heat generation effect during the dynamic use of the tire. At the same time, the compound filling system of nano-silica and carbon black, with the assistance of a silane coupling agent, achieves a balance between low rolling resistance and high wear resistance. The DIN wear value of the tread rubber decreases and the tear resistance strength increases, directly extending the service life of the tire under complex road conditions.

[0083] In the present invention, the use of vegetable oil-based plasticizers to replace traditional petroleum-based plasticizers not only reduces the dependence on non-renewable resources but also reduces the emission of volatile organic compounds during the production process, meeting the environmental protection standards of green tires. The composite anti-aging system of anti-aging agents and microcrystalline wax effectively inhibits thermal-oxidative aging and ozone cracking through dual mechanisms of chemical blocking and physical shielding. After 72 hours of thermal-oxidative aging at 70 degrees Celsius, the tensile strength retention rate of the rubber compound exceeds 85%, far exceeding 70% of the conventional formulation. In addition, the two-stage vulcanization process, while ensuring the stability of the crosslinking network, reduces the risk of over-vulcanization, increasing the comprehensive durability of the finished tire by more than 30% and taking into account the requirements of energy conservation and long-term use.

[0084] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0085] The above description enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rare earth rubber vulcanizing agent for extending the service life of tires, characterized in that: The vulcanizing agent includes: 70 parts by weight of natural rubber, 30 parts by weight of styrene-butadiene rubber, 3 - 5 parts by weight of lanthanum oxide, 1.5 parts by weight of sulfur, 40 parts by weight of nano-sized silica, 20 parts by weight of carbon black, 2 parts by weight of silane coupling agent Si69, 2 parts by weight of antioxidant, 1 part by weight of microcrystalline wax, 3 parts by weight of zinc oxide, 1 part by weight of stearic acid, and 5 parts by weight of vegetable oil-based plasticizer.

2. The production method of a rare earth rubber vulcanizing agent for extending the service life of tires according to claim 1, characterized in that: The production method includes the following steps: S1: Mix lanthanum oxide and nano-sized silica in proportion, add them to a ball mill for dry grinding for 2 hours, with the ball mill rotation speed at 300 rpm, so that the particle size of lanthanum oxide is reduced to 50 to 100 nanometers, and a pre-dispersed complex is formed with silica. S2: Put natural rubber and styrene-butadiene rubber into an internal mixer, set the temperature of the internal mixer at 80 to 90 °C, and sequentially add stearic acid, zinc oxide, and vegetable oil-based plasticizer, and knead for 3 minutes until the rubber compound is uniformly plasticized. S3: Add the pretreated lanthanum oxide and silica complex, carbon black, and silane coupling agent Si69 to the internal mixer, control the kneading temperature not to exceed 120 °C, and knead for 6 minutes until the fillers are completely dispersed. S4: Add sulfur, antioxidant 4020, and microcrystalline wax, lower the kneading temperature to 70 to 80 °C, and continue kneading for 2 minutes to prevent premature reaction of sulfur. S5: Transfer the kneaded rubber compound to a two-roll mill for thin-sheeting 3 times, keep the roll temperature of the two-roll mill at 50 °C, and after sheeting, place it in an environment at 25 °C and let it stand for 24 hours. S6: Preheat the standing rubber compound to 60 °C, and form it into tire components through an extruder or calender, controlling the thickness tolerance within the range of plus or minus 0.1 mm. S7: Put the formed rubber compound into a vulcanization mold for two-stage vulcanization: The temperature of the first-stage vulcanization is 150 °C, the pressure is 15 MPa, and the vulcanization time is determined according to T90 measured by a rheometer, usually 80% of the vulcanization time of the traditional formula. The temperature of the second-stage vulcanization is 120 °C, and vulcanize under normal pressure for 2 hours to stabilize the cross-linked network. S8: After vulcanization, the tire components are trimmed and cooled to room temperature, and optionally, an anti-ozone wax coating can be sprayed to enhance surface protection. S9: Conduct abrasion resistance test, dynamic heat generation test, and thermal-oxidative aging test on the finished product. The detection standards are DIN abrasion method, Goodrich flexing test, and thermal-oxidative aging at 70 °C for 72 hours respectively. After passing the tests, store them in the warehouse.

3. The production method of a rare earth rubber vulcanizing agent for extending the service life of tires according to claim 1, characterized in that: In step S1, after mixing lanthanum oxide and nano-sized silica according to the formula ratio, put them into a planetary ball mill for dry grinding treatment; set the rotation speed of the ball mill at 300 revolutions per minute, the grinding time is 2 hours, the grinding medium is zirconia ceramic balls, and the ball-to-material ratio is 10:1; strictly control the temperature not to exceed 50 °C during the grinding process, and prevent the material from overheating through intermittent cooling; the ground mixed material needs to be detected by a laser particle size analyzer to ensure that the particle size distribution of lanthanum oxide is within the range of 50 to 100 nanometers.

4. The production method of a rare earth rubber vulcanizing agent for prolonging the service life of a tire according to claim 1, characterized in that: In step S2, natural rubber and styrene-butadiene rubber are put into a Banbury mixer. The initial temperature of the Banbury mixer is set at 80 °C, and the rotor speed is adjusted to 60 revolutions per minute. Stearic acid, zinc oxide, and vegetable oil-based plasticizer are added in sequence, with a feeding interval of 30 seconds to ensure uniform mixing. During the mixing process, the temperature of the Banbury mixer gradually rises, and the temperature needs to be controlled below 90 °C through a circulating water cooling system. The total mixing time is 3 minutes. The final rubber compound shows a plasticized state without particle sense and smooth surface, and its Mooney viscosity is detected by a Hake rheometer to ensure that it reaches the standard range of 45±5 ML.

5. The production method of a rare earth rubber vulcanizing agent for extending the service life of tires according to claim 1, characterized in that: In step S3, after the temperature of the Banbury mixer drops to 100 °C, the pretreated lanthanum oxide and silica complex, carbon black N330, and silane coupling agent Si69 are added. The rotor speed of the Banbury mixer is increased to 80 revolutions per minute, and the mixing temperature is strictly limited within 120 °C through a PID control system. The mixing time is 6 minutes. During this period, the dispersion state of the filler is monitored through the torque change curve. When the torque is stable within the ±5% fluctuation range, it is considered that the dispersion is complete.

6. The production method of a rare earth rubber vulcanizing agent for extending the service life of tires according to claim 1, characterized in that: In step S4, the temperature of the Banbury mixer is adjusted to 70 °C, and the rotor speed is reduced to 40 revolutions per minute. Sulfur, antioxidant 4020, and microcrystalline wax are added in sequence. The mixing time is 2 minutes. During the process, the temperature shall not exceed 80 °C to prevent premature cross-linking reaction caused by sulfur. After the feeding is completed, the vulcanization characteristics of the rubber compound are tested by rapid sampling of the rubber compound, and the scorch time measured by a rotorless vulcanizer is greater than 5 minutes.

7. The production method of a rare earth rubber vulcanizing agent for extending the service life of tires according to claim 1, characterized in that: In step S5, the mixed rubber compound is discharged from the bottom plug of the Banbury mixer to a two-roll mill. The temperature of the roll is set at 50 °C, and the roll gap is adjusted to 1 mm for three passes of thin-sheeting. After thin-sheeting, the thickness of the rubber compound sheet is controlled within 2.5±0.2 mm, and then it is transferred to a constant temperature and humidity chamber and left standing for 24 hours in an environment of 25 °C and relative humidity of 50%. During the standing process, the internal stress of the rubber compound is gradually released, and the fluctuation of its storage modulus detected by a dynamic thermomechanical analyzer needs to be less than 5%.

8. The production method of a rare earth rubber vulcanizing agent for extending the service life of tires as described in claim 1, characterized in that: In step S6, the standing rubber compound is preheated to 60 °C in a hot air circulation oven and kept for 20 minutes, and then it is formed by a Φ120mm cold-feed extruder or a three-roll calender. The screw speed of the extruder is set at 30 revolutions per minute, the die temperature is controlled at 70 °C, and the thickness tolerance of the formed tread rubber is ±0.1 mm. The roll temperature gradient of the calender is set at 60 °C for the lower roll, 65 °C for the middle roll, and 70 °C for the upper roll to ensure the fluidity and dimensional accuracy of the rubber compound.

9. The production method of a rare earth rubber vulcanizing agent for extending the service life of tires according to claim 1, characterized in that: In step S7, the formed rubber compound is loaded into a preheated tire vulcanization mold, and two-stage vulcanization is carried out using an electric heating flat vulcanizer. The conditions for the first-stage vulcanization are a temperature of 150 °C, a pressure of 15 MPa, and the vulcanization time is determined according to the optimum vulcanization time T90 measured by the rheometer.

10. The production method of a rare earth rubber vulcanizing agent for prolonging the service life of tires as described in claim 1, characterized in that: In the step S8, the vulcanized tire component is trimmed by a water cutting machine to remove the flash, and then the temperature is reduced from 120 °C to room temperature within 15 minutes through a spray cooling system; for surface treatment, a high-pressure airless spraying device is used to spray an anti-ozone wax coating with a thickness of 10 to 15 microns. The spraying pressure is set at 20 MPa, the nozzle diameter is 0.5 mm, and it needs to be dried in a drying oven at 40 °C for 10 minutes after spraying to form a continuous protective film; In the step S9, the finished tire component is subjected to a full range of tests according to ISO standards: the wear resistance is tested using a DIN abrasion tester, and the abrasion volume should be less than 120 cubic millimeters; the dynamic heat generation is determined by a Goodrich flexometer, and the temperature rise should not exceed 30 °C; The thermal oxygen aging test is carried out in an oven at 70 °C for 72 hours, and the retention rate of the tensile strength after aging should be greater than 85%.

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