Synthesis method of bio-based dendritic phosphate derivative and application of bio-based dendritic phosphate derivative in tire tread rubber

Abstract

The invention belongs to the technical field of rubber processing, and discloses a synthesis method of a bio-based dendritic phosphate derivative, which comprises the following specific steps: step 1, esterification reaction: mixing ricinoleic acid and glycerol according to a molar ratio of 1: 1.2, adding 0.3% p-toluenesulfonic acid as a catalyst, and reacting at 180 DEG C for 3 hours until the acid value of a reaction system is less than or equal to 5 mgKOH / g and the acid value of the ricinoleic acid is more than or equal to 180 mgKOH / g; the composition is high in bio-based content, extremely low in PAHs content and high in biodegradation rate, and strict environmental protection laws and regulations are met from the source; meanwhile, a single molecule has plasticizing, interface enhancing and potential flame-retardant functions, so that the Mooney viscosity of a rubber material can be effectively reduced, the interface bonding strength of rubber and filler is improved, and reversible dynamic crosslinking can be generated at high temperature to adapt to the dynamic working condition of a tire; in the aspect of performance, the auxiliary agent can obviously reduce the tan delta value of tread rubber at 60 DEG C, increase the tan delta value at 0 DEG C and reduce DIN abrasion, so that the rolling resistance, the wet-skid performance and the abrasion resistance are synergistically improved.

Description

Technical Field

[0001] This invention belongs to the field of rubber processing technology, specifically a method for synthesizing bio-based dendritic phosphate derivatives and their application in tire tread rubber. Background Technology

[0002] Bio-based dendritic phosphate derivatives are a class of phosphate compounds with a dendritic molecular topology, prepared using bio-based raw materials as the core.

[0003] The "devil's triangle" of tire performance—the difficulty in simultaneously achieving rolling resistance, wet grip, and wear resistance—has long been a challenge for the industry. While traditional petroleum-based processing oils (such as aromatic and naphthenic oils) can improve processability, they suffer from high polycyclic aromatic hydrocarbon content, significant environmental pollution, and poor biodegradability. Furthermore, their single function fails to synergistically improve multiple key tire performance characteristics. With the tightening of EU REACH and other environmental regulations, and the surge in demand for low rolling resistance tires from new energy vehicles, the development of high-performance, environmentally friendly processing oil alternatives is urgently needed. Among existing technologies, some research has attempted to use phosphoric acid. Esters are used as plasticizers or flame retardants. For example, patent CN119570128A discloses a modified trioctyl phosphate. Although it reduces the PAH content, its molecular structure is symmetrical and its bonding force with the rubber / filler interface is insufficient, resulting in limited reinforcement effect. Moreover, the raw materials are mainly petroleum-based, which does not conform to the trend of sustainable development. In addition, it lacks temperature responsiveness and is difficult to adapt to the wide range of temperature changes during tire operation. Therefore, there is an urgent need to develop a new type of multifunctional additive that combines high performance, high bio-based content, environmental friendliness, and the ability to balance the "devil's triangle" of tires. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for synthesizing bio-based dendritic phosphate derivatives and their application in tire tread rubber, thereby solving the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for synthesizing bio-based dendritic phosphate derivatives, the specific steps of which are as follows: Step 1: Esterification reaction Ricinoleic acid and glycerol were mixed at a molar ratio of 1:1.2, and 0.3% p-toluenesulfonic acid was added as a catalyst. The mixture was reacted at 180°C for 3 hours until the acid value of the reaction system was ≤5 mgKOH / g, of which the acid value of ricinoleic acid was ≥180 mgKOH / g. Step 2: Phosphorylation Modification Add to the product obtained in step one The urea-urea mixture was heated to 85°C and maintained at that temperature for 2 hours under nitrogen protection. The reaction was monitored in real time by high performance liquid chromatography to ensure that the phosphorylation degree of the product was ≥92%. Step 3: Dendritic modification Phosphorus oxychloride was added to the phosphorylated product obtained in step two, and the reaction was carried out at 0.1 MPa pressure and 120 °C for 1.5 h until the chloride ion content of the system was <0.1%, thus obtaining a bio-based dendritic phosphate derivative.

[0006] Preferably, the molecular structure of the bio-based dendritic phosphate derivative described in step three is as follows: The core unit is glycerol phosphate, in which bio-based raw materials account for ≥60%; the branched structure includes: Branch A: C8-C12 alkyl chain, accounting for 35%~45% of the total weight of the bio-based dendritic phosphate derivative; Branch B: Glycidyl ether group, accounting for 25% to 35% of the total weight of the bio-based dendritic phosphate derivative; Branch C: Phosphate ester group, accounting for 20% to 30% of the total weight of the bio-based dendritic phosphate derivative; The bio-based dendritic phosphate derivative has a molecular weight of 800~1200 Da, a molecular weight distribution index (PDI) ≤1.3, and a bio-based content ≥85%.

[0007] Preferably, the step two described The mass ratio of the urea-mixed reagent is 3:1. The urea-urea mixture can form a stable phosphorylated active intermediate in the reaction system.

[0008] Preferably, the reaction temperature in step two is allowed an error range of ±5℃, that is, the reaction temperature range is 80℃~90℃. Within this temperature range, The reactivity of the urea mixture reagent is well matched with the reactivity of the esterification product.

[0009] Preferably, the amount of phosphorus oxychloride used in step three is 1.1 times the theoretical value, where the theoretical value is the stoichiometric value of phosphorus oxychloride required for complete reaction with the hydroxyl groups in the phosphorylated product obtained in step two.

[0010] Application of bio-based dendritic phosphate derivatives in tire tread compounds: In the application formulation system, the bio-based dendritic phosphate derivatives are used as processing oils, replacing traditional petroleum-based processing oils, and are combined with rubber, fillers, and vulcanization systems to prepare tire tread compounds through the following process: First-stage compounding: The rubber matrix and silica are mixed at 140-150℃ for 4-6 minutes to obtain a first-stage compound; Second-stage mixing: Cool the first-stage compound to 100-120℃, add bio-based dendritic phosphate derivatives, vulcanization system and other rubber additives, and mix for 2-4 minutes. Vulcanization treatment: at 153-157℃ and 1.2MPa pressure, the vulcanization time is calculated at 1.5 minutes / mm according to the thickness of the rubber compound. After vulcanization is completed, the rubber compound is naturally cooled to room temperature to obtain the tire tread rubber.

[0011] Preferably, the specific surface area of ​​the silica is 180 m² / g; when applied to winter tire formulations, it also includes 5% nano-SiO2 with a particle size of 25 nm and a surface hydroxyl content of 3.8 mmol / g and 2% silane coupling agent Si-69 with a purity of 99.5%.

[0012] Preferably, the vulcanization treatment is carried out using a flat vulcanizing machine, and the pressure fluctuation during the vulcanization process is kept within ±0.05MPa, and the temperature deviation is controlled within ±1℃.

[0013] Preferably, the tire tread compound is suitable for the manufacture of passenger car tires or commercial vehicle tires.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This composition boasts a high bio-based content, extremely low PAH content, and high biodegradability, meeting stringent environmental regulations from the source. Simultaneously, its individual molecules possess plasticizing, interfacial strengthening, and potential flame-retardant functions, effectively reducing Mooney viscosity and enhancing the interfacial bonding strength between rubber and fillers. Furthermore, it undergoes reversible dynamic cross-linking at high temperatures, adapting to tire dynamic conditions. In terms of performance, this additive significantly reduces the tanδ value of the tread compound at 60°C, increases the tanδ value at 0°C, and reduces DIN wear, thereby synergistically improving rolling resistance, wet skid performance, and abrasion resistance. Moreover, its synthesis process employs a green catalytic system, resulting in low energy consumption and low COD in wastewater, adhering to green chemistry principles and providing a high-performance and sustainable solution for replacing traditional petroleum-based processing oils. Detailed Implementation

[0015] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1: Synthesis and application of bio-based dendritic phosphate derivatives for summer tire formulations The specific steps for synthesizing bio-based dendritic phosphate derivatives are as follows: Step 1: Esterification reaction Ricinoleic acid and glycerol were mixed at a molar ratio of 1:1.2, and 0.3% p-toluenesulfonic acid was added as a catalyst. The mixture was reacted at 180°C for 3 hours until the acid value of the reaction system was ≤5 mgKOH / g, of which the acid value of ricinoleic acid was ≥180 mgKOH / g. Step 2: Phosphorylation Modification Add to the product obtained in step one The urea-urea mixture was heated to 85°C and maintained at that temperature for 2 hours under nitrogen protection. The reaction was monitored in real time by high performance liquid chromatography to ensure that the phosphorylation degree of the product was ≥92%. Step 3: Dendritic modification Phosphorus oxychloride was added to the phosphorylated product obtained in step two, and the reaction was carried out at 0.1 MPa pressure and 120 °C for 1.5 h until the chloride ion content of the system was <0.1%, thus obtaining a bio-based dendritic phosphate derivative.

[0017] The three-step reaction is logically coherent and highly targeted. The esterification reaction uses high-acid-value ricinoleic acid as a bio-based raw material, and the molar ratio and catalyst dosage are precisely controlled to lay a stable molecular framework for subsequent modification. The phosphorylation modification achieves efficient directional phosphorylation through a specific ratio of reagents and nitrogen protection, and temperature control, ensuring the conversion rate of functional groups in the product. The dendrite modification precisely controls the pressure and temperature, strictly controls chloride ion residue, and ensures the uniformity of product structure. The overall process conditions are mild and easy to control, without the need for extreme reaction environments, and balances high bio-based content and product purity. It also has low energy consumption and few side reactions. With real-time monitoring, it effectively ensures the stability of product performance and meets the needs of green synthesis and industrial production.

[0018] The molecular structure of the bio-based dendritic phosphate derivative in step three is as follows: The core unit is glycerophosphate, and the proportion of bio-based raw materials in glycerophosphate is ≥60%; the branch structure includes: Branch A: C8-C12 alkyl chain, accounting for 35%~45% of the total weight of bio-based dendritic phosphate derivatives; Branch B: Glycidyl ether group, accounting for 25%~35% of the total weight of the bio-based dendritic phosphate derivative; Branch C: Phosphate ester group, accounting for 20%~30% of the total weight of bio-based dendritic phosphate ester derivatives; The bio-based dendritic phosphate derivatives have a molecular weight of 800~1200 Da, a molecular weight distribution index (PDI) ≤1.3, and a bio-based content ≥85%.

[0019] The core unit, glyceryl phosphate, has a high bio-based content of ≥60%. Combined with the synergistic effect of three functional branches, the C8-C12 alkyl chain efficiently exerts its plasticizing effect, the glycidyl ether group strengthens the interface between rubber and filler, and the phosphate ester group imparts potential flame retardant properties. The precise control of molecular weight and PDI ensures the uniformity of product structure and processing adaptability. The bio-based content of more than 85% and the low PAHs characteristics meet the requirements of environmental protection regulations. The overall structure achieves multi-functional integration of environmental protection, processability, interface enhancement and temperature response. It not only solves the problems of single function and poor environmental protection of traditional petroleum-based processing oils, but also makes up for the defects of insufficient interface bonding of existing phosphate ester substances, providing core support for the performance balance of the tire "devil triangle".

[0020] In step two The mass ratio of urea to the reagent is 3:1. The urea-urea mixture can form a stable phosphorylated active intermediate in the reaction system.

[0021] Precise proportions Synergistically with urea, it efficiently forms a stable phosphorylation intermediate, ensuring the directional insertion of the phosphoryl group into the target molecule and guaranteeing a phosphorylation degree ≥92%; simultaneously, this ratio avoids... Excessive amounts can lead to excessive local acidity in the system and side reactions such as oxidation and carbonization of bio-based raw materials. However, excessive urea content can also reduce reaction activity and produce viscous byproducts, thus significantly improving product yield and purity.

[0022] In step two, the reaction temperature is allowed an error range of ±5℃, meaning the reaction temperature range is 80℃~90℃. Within this temperature range... The reactivity of the urea mixture reagent is well matched with the reactivity of the esterification product.

[0023] An error range of 80℃~90℃ ensures The precise matching of the reactivity of the urea mixture with the esterification product ensures efficient and directional phosphorylation, maintaining a stable phosphorylation degree of ≥92%. It also reduces the difficulty of temperature control and avoids side reactions caused by temperature fluctuations. Compared with a single fixed temperature, this range has a higher tolerance for error and can be adapted to the temperature control accuracy of different production equipment, reducing product performance fluctuations caused by equipment differences. It balances reaction efficiency, product quality stability, and industrial operability, further reducing production losses.

[0024] In step three, the amount of phosphorus oxychloride used is 1.1 times the theoretical value, which is the stoichiometric value of phosphorus oxychloride required for complete reaction with the hydroxyl groups in the phosphorylated product obtained in step two.

[0025] The 10% excess of phosphorus oxychloride ensures sufficient reaction with the hydroxyl groups in the phosphorylated product, avoiding incomplete dendration modification due to insufficient raw materials and guaranteeing the integrity and uniformity of the product's molecular structure. At the same time, the moderate excess of phosphorus oxychloride can promote the reaction forward, improve the yield of the target product, and will not cause side reactions or increase the difficulty of subsequent separation and purification due to excessive amount. This design not only conforms to the laws of chemical reaction kinetics, but also meets the actual needs of raw material reaction efficiency in industrial production, laying the structural foundation for the stable performance of the product in terms of interface enhancement and temperature response.

[0026] Application of Bio-based Dendritic Phosphate Derivatives in Tire Tread Compounds: In application formulation systems, bio-based dendritic phosphate derivatives are used as processing oils, replacing traditional petroleum-based processing oils, and are combined with rubber, fillers, and vulcanization systems to prepare tire tread compounds through the following processes: First stage of compounding: Mix 100 phr of rubber with 50 phr of silica at 140-150℃ for 4-6 minutes to obtain a first stage of compounded rubber; Second-stage mixing: Cool the first-stage compound to 100-120℃, add bio-based dendritic phosphate derivatives, vulcanization system and other rubber additives, and mix for 2-4 minutes. Vulcanization treatment: at 153-157℃ and 1.2MPa pressure, the vulcanization time is calculated at 1.5 minutes / mm according to the thickness of the rubber compound. After vulcanization is completed, the rubber compound is naturally cooled to room temperature to obtain the tire tread rubber.

[0027] By replacing traditional petroleum-based processing oils with bio-based dendritic phosphate derivatives, environmental concerns are addressed at the source, meeting stringent regulatory requirements. The two-stage mixing process employs a gradient temperature control mode. The first stage, at a high temperature, ensures uniform dispersion of fillers in the rubber matrix, while the second stage, after cooling, introduces functional components, preventing premature activation of the vulcanization system and heat loss of derivatives, thus ensuring synergistic effects of all components. Vulcanization parameters are precisely matched to product characteristics, and stable vulcanization time is achieved with appropriate temperature, pressure, and thickness, promoting the formation of a dense cross-linked network in the rubber compound and fully stimulating the plasticizing and interfacial strengthening functions of the bio-based derivatives.

[0028] The specific surface area of ​​silica is 180 m² / g.

[0029] With a specific surface area of ​​180 m² / g, silica possesses a highly active surface and excellent reinforcing potential. It can form a strong interaction with the glycidyl ether groups of bio-based dendritic phosphate derivatives, significantly improving the bonding strength of the rubber-filler interface and preventing filler agglomeration.

[0030] The vulcanization process is carried out using a flat vulcanizing machine. During the vulcanization process, the pressure fluctuation is kept within ±0.05MPa and the temperature deviation is controlled within ±1℃.

[0031] The application of flat vulcanizing machines, combined with stringent temperature and pressure control standards, ensures that the rubber compound is vulcanized uniformly in a stable environment, avoiding local over-vulcanization or under-vulcanization.

[0032] Among them, tire tread compound is suitable for the manufacture of passenger car tires or commercial vehicle tires.

[0033] Passenger car tires have high requirements for low rolling resistance and wet safety, while commercial vehicle tires focus on wear resistance and long mileage. This tread compound, through a performance balance design, can meet the core requirements of both types of tires at the same time.

[0034] Performance test results: tanδ(0℃)=0.41, tanδ(60℃)=0.026; DIN wear amount 68mm³; rolling resistance coefficient 7.0kg / t; wet braking distance reduced by 1.4m.

[0035] The optimized tanδ value achieves a synergistic improvement in wet skid performance and rolling resistance, while the low DIN wear amount demonstrates excellent wear resistance, significantly solving the "devil's triangle" problem. The rolling resistance coefficient meets the EU Class B standard, and the wet braking distance is significantly shortened, which not only meets the low heat generation requirements of new energy vehicles, but also improves driving safety and comprehensively ensures the product's market competitiveness.

[0036] Example 2: Application of bio-based dendritic phosphate derivatives in winter tire formulations Formula adjustment: Based on the formula of Example 1, 5% nano SiO2 with a particle size of 25nm and a surface hydroxyl content of 3.8mmol / g and 2% silane coupling agent Si-69 with a purity of 99.5% were added; Preparation process: Same as the mixing and vulcanization process in Example 1; Performance testing: Glass transition temperature -58℃; coefficient of friction on ice surface 0.42; tanδ(0℃)=0.43, tanδ(60℃)=0.027; DIN wear amount 70mm³, meeting the low-temperature performance and wear resistance requirements of winter tires.

[0037] By adding nano-SiO2 of specific specifications and silane coupling agent Si-69, the high dispersibility and high hydroxyl content of nano-SiO2, along with the bridging effect of the coupling agent, strengthen the interfacial bonding with bio-based derivatives and rubber matrix.

[0038] Example 3: Application of bio-based dendritic phosphate derivatives in all-season tire formulations Formula: 100 phr rubber, 45 phr silica, 12 phr bio-based dendritic phosphate derivative, 5 phr vulcanization system; Preparation process: Same as the mixing and vulcanization process in Example 1; Performance testing: tanδ shows a smooth transition in the range of -20℃ to 80℃; the energy storage modulus decreases by 35% at 120℃; after 50,000 kilometers of actual mixed road testing, the performance degradation of each item is less than 8%; the rolling resistance coefficient is 7.1kg / t, the wet braking distance is shortened by 1.3m, and the wear mileage is increased by 23% compared with the traditional formula.

[0039] The tanδ temperature range is smooth from -20℃ to 80℃, and the energy storage modulus decreases moderately at 120℃, perfectly adapting to seasonal temperature changes and tire dynamic conditions; the performance degradation is less than 8% after 50,000 kilometers of road testing, demonstrating long-term stability.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for synthesizing bio-based dendritic phosphate derivatives, characterized in that, The specific steps are as follows: Step 1: Esterification reaction Ricinoleic acid and glycerol were mixed at a molar ratio of 1:1.2, and 0.3% p-toluenesulfonic acid was added as a catalyst. The mixture was reacted at 180°C for 3 hours until the acid value of the reaction system was ≤5 mgKOH / g, of which the acid value of ricinoleic acid was ≥180 mgKOH / g. Step 2: Phosphorylation Modification Add to the product obtained in step one The urea-urea mixture was heated to 85°C and maintained at that temperature for 2 hours under nitrogen protection. The reaction was monitored in real time by high performance liquid chromatography to ensure that the phosphorylation degree of the product was ≥92%. Step 3: Dendritic modification Phosphorus oxychloride was added to the phosphorylated product obtained in step two, and the reaction was carried out at 0.1 MPa pressure and 120 °C for 1.5 h until the chloride ion content of the system was <0.1%, thus obtaining a bio-based dendritic phosphate derivative.

2. The method for synthesizing the bio-based dendritic phosphate derivative according to claim 1, characterized in that: The molecular structure of the bio-based dendritic phosphate derivative described in step three is as follows: The core unit is glyceryl phosphate, in which bio-based raw materials account for ≥60%; the branched structure includes: Branch A: C8-C12 alkyl chain, accounting for 35%~45% of the total weight of the bio-based dendritic phosphate derivative; Branch B: Glycidyl ether group, accounting for 25% to 35% of the total weight of the bio-based dendritic phosphate derivative; Branch C: Phosphate ester group, accounting for 20% to 30% of the total weight of the bio-based dendritic phosphate derivative; The bio-based dendritic phosphate derivative has a molecular weight of 800~1200 Da, a molecular weight distribution index (PDI) ≤1.3, and a bio-based content ≥85%.

3. The method for synthesizing the bio-based dendritic phosphate derivative according to claim 1, characterized in that: The steps described in step two The mass ratio of the urea-mixed reagent is 3:

1. The urea-urea mixture can form a stable phosphorylated active intermediate in the reaction system.

4. The method for synthesizing the bio-based dendritic phosphate derivative according to claim 1, characterized in that: The reaction temperature in step two is allowed an error range of ±5℃, that is, the reaction temperature range is 80℃~90℃. Within this temperature range, The reactivity of the urea mixture reagent is well matched with the reactivity of the esterification product.

5. The method for synthesizing the bio-based dendritic phosphate derivative according to claim 1, characterized in that: The amount of phosphorus oxychloride used in step three is 1.1 times the theoretical value, which is the stoichiometric value of phosphorus oxychloride required for complete reaction with the hydroxyl groups in the phosphorylated product obtained in step two.

6. The application of the bio-based dendritic phosphate derivative prepared according to the synthesis method of claims 1-5 in tire tread rubber, characterized in that: In the application formulation system, the bio-based dendritic phosphate derivative is used as an operating oil to replace traditional petroleum-based operating oils. It is combined with rubber, fillers, and vulcanization systems to prepare tire tread rubber through the following process: First-stage compounding: The rubber matrix and silica are mixed at 140-150℃ for 4-6 minutes to obtain a first-stage compound; Second-stage mixing: Cool the first-stage compound to 100-120℃, add bio-based dendritic phosphate derivatives, vulcanization system and other rubber additives, and mix for 2-4 minutes. Vulcanization treatment: at 153-157℃ and 1.2MPa pressure, the vulcanization time is calculated at 1.5 minutes / mm according to the thickness of the rubber compound. After vulcanization is completed, the rubber compound is naturally cooled to room temperature to obtain the tire tread rubber.

7. The application of the bio-based dendritic phosphate derivative according to claim 6 in tire tread compound, characterized in that: The specific surface area of ​​the silica is 180 m² / g; when applied to winter tire formulations, it also includes 5% nano-SiO2 with a particle size of 25 nm and a surface hydroxyl content of 3.8 mmol / g and 2% silane coupling agent Si-69 with a purity of 99.5%.

8. The application of the bio-based dendritic phosphate derivative according to claim 6 in tire tread compound, characterized in that: The vulcanization process is carried out using a flat vulcanizing machine. During the vulcanization process, the pressure fluctuation is kept within ±0.05MPa and the temperature deviation is controlled within ±1℃.

9. The application of the bio-based dendritic phosphate derivative according to claim 6 in tire tread compound, characterized in that: The tire tread compound is suitable for the manufacture of passenger car tires or commercial vehicle tires.