Preparation process and application of cobalt salt adhesion promoter

Abstract

The invention discloses a preparation process and application of a cobalt salt adhesion promoter, and relates to the technical field of preparation processes of promoters, the preparation process comprises the following steps: S1, activating and drying cobalt hydroxide; s2, mixing the pretreated cobalt hydroxide with a compound containing an imidazole group in a water medium; s3, in the reaction stage, near-infrared and Raman spectrum fusion is adopted to monitor the reaction progress and automatically remove interference signals, and in the drying stage, dual verification is performed on the moisture and crystal structure of the product; and S4, washing and drying the bluish violet slurry to obtain the imidazole group-containing compound cobalt of the cobalt salt adhesion promoter. According to the method, near-infrared pre-monitoring is combined with dynamic threshold judgment logic, and differential secondary activation and secondary spraying strategies are matched, so that the problems of inaccurate evaluation of activation degrees of different batches of cobalt hydroxide and insufficient differential removal of impurity contents are solved, and the effect that the reaction activity of the pretreated cobalt hydroxide is basically consistent is achieved; the target of avoiding the influence of the raw material quality fluctuation on the subsequent process from the source is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of preparation process of adhesion promoter, and particularly relates to a preparation process and application of cobalt salt adhesion promoter. BACKGROUND

[0002] In the adhesion system of rubber and base material (such as steel cord, carbon fiber, etc.), cobalt salt adhesion promoter is a key material for improving adhesion strength and durability, and is particularly suitable for rubber products such as new energy automobile tires which are subjected to high load and high torque working conditions. The traditional cobalt salt adhesion promoter has the problem of insufficient adhesion stability, and the compound cobalt containing imidazole group as a new type of cobalt salt material will become a research hotspot in the industry due to its excellent initial and aged adhesion performance.

[0003] In the prior art, the compound cobalt containing imidazole group is synthesized by one-step method, and is prepared by reacting cobalt hydroxide and a compound containing imidazole group in water medium. This process has the advantages of simple operation, low cost and easy industrialization. However, in the actual production process, the activation degree of different batches of cobalt hydroxide varies, and the surface hydroxyl activity is greatly affected by factors such as production process and storage conditions. In addition, industrial-grade cobalt hydroxide often contains impurities such as calcium and magnesium, and there is no unified control standard for impurity content, and the difference between batches is obvious.

[0004] The key problem is that the existing pretreatment process neither accurately evaluates the activation degree (hydroxyl activity) of different batches of cobalt hydroxide, nor adopts a differentiated removal strategy according to the difference in impurity content. Only a unified drying and washing process is used, which leads to the fact that the pretreated cobalt hydroxide cannot form a stable and consistent reaction activity basis. This defect directly leads to unstable coordination reaction activity, which is manifested as fluctuation of reaction rate, large dispersion of product yield and cobalt content, and finally leads to poor consistency of the adhesion performance of the compound cobalt containing imidazole group, which cannot meet the strict requirements of high-end rubber products on the stability of raw material quality. SUMMARY

[0005] The purpose of the present application is to provide a preparation process and application of cobalt salt adhesion promoter to solve the problems raised in the background art.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a preparation process of cobalt salt adhesion promoter, comprising the following steps: S1, after activating and drying the cobalt hydroxide, impurities are removed by spraying dilute hydrochloric acid combined with material overturning, and the characteristic indexes of the activated cobalt hydroxide are evaluated by near-infrared monitoring combined with dynamic threshold to output calibration parameters for subsequent process control; S2, mixing the pretreated cobalt hydroxide and the compound containing imidazole group in a water medium, stirring and reacting at normal temperature and pressure to obtain a blue-purple slurry; S3, the reaction stage uses near-infrared and Raman spectrum fusion to monitor the reaction progress and automatically remove interference signals, the drying stage double verifies the moisture and crystal structure of the product, and according to the near-infrared pre-monitoring result of step S1 after dynamic threshold evaluation, dynamically calibrates the reaction and drying parameters; S4, washing and drying the blue-purple slurry to obtain a cobalt salt adhesion enhancer containing imidazole group compound cobalt.

[0007] Preferably, the dynamic threshold evaluation process of near-infrared pre-monitoring in step S1 includes: S11, collecting the raw material characteristic parameters of the cobalt hydroxide to be processed, the raw material characteristic parameters including physical form parameters or source information; S12, setting an initial reference hydroxyl characteristic peak intensity threshold and a reference impurity characteristic peak total intensity threshold; S13, according to the raw material characteristic parameters, and querying a historical database containing the correlation between the raw material characteristic parameters and the reaction activity and product purity, adaptively adjusting the reference hydroxyl characteristic peak intensity threshold and the reference impurity characteristic peak total intensity threshold; S14, for the raw material batches without corresponding data in the historical database, pre-monitoring is performed according to the reference threshold or the calibrated threshold, and the effectiveness of the threshold is verified according to the results of the subsequent coordination reaction, the threshold verified to be effective is associated with the raw material characteristic parameters and updated to the historical database.

[0008] Preferably, the impurity removal of the step S1 is divided into three stages by spraying dilute hydrochloric acid combined with material overturning, and is realized by using a single adjustable nozzle, specifically including: Stage 1: using low-concentration dilute hydrochloric acid, low spraying rate, first nozzle angle, first material overturning speed, for a first preset time, to preferentially remove calcium impurities on the surface of cobalt hydroxide; Stage 2: using medium-concentration dilute hydrochloric acid, high spraying rate, second nozzle angle, second material overturning speed, for a second preset time, to penetrate and remove magnesium impurities inside the cobalt hydroxide agglomerates; Stage 3: using low-concentration dilute hydrochloric acid, low spraying rate, first nozzle angle, third material overturning speed, for a third preset time, to flush the residual high-concentration acid solution.

[0009] Preferably, after the dilute hydrochloric acid spraying in step S1, the process of inert protection and rapid dehydration of the cobalt hydroxide is further included: The sprayed cobalt hydroxide is placed in an inert gas atmosphere, vacuum filtration is performed at a suitable vacuum degree to realize solid-liquid separation, and vacuum drying is immediately performed at a suitable temperature for a suitable time to control the water content of the cobalt hydroxide to meet the requirements of a subsequent coordination reaction and the oxidation rate to meet the requirements of the subsequent coordination reaction.

[0010] Preferably, if the near-infrared pre-monitoring result in the step S1 does not meet the threshold value after dynamic calibration, the parameter compensation adjustment process further includes the following steps: If the hydroxyl characteristic peak intensity is less than the calibrated hydroxyl threshold value, the cobalt hydroxide is sent to the activation drying device again, vacuum drying is performed at a suitable temperature for a suitable time for secondary activation, and near-infrared pre-monitoring is performed again according to the dynamic threshold evaluation logic after the secondary activation until the hydroxyl characteristic peak intensity is greater than or equal to the calibrated hydroxyl threshold value. If the total impurity characteristic peak intensity is greater than the calibrated impurity threshold value, the cobalt hydroxide is sprayed with secondary dilute hydrochloric acid, the secondary spraying uses dilute hydrochloric acid with a suitable concentration, a suitable spraying rate, a third nozzle angle, and a fourth material overturning speed, and is continued for a fourth preset time, and near-infrared pre-monitoring is performed again according to the dynamic threshold evaluation logic after the secondary spraying until the total impurity characteristic peak intensity is less than or equal to the calibrated impurity threshold value.

[0011] Preferably, the material ratio process of the coordination reaction in the step S2 includes the following steps: The compound containing an imidazole group, the pretreated cobalt hydroxide, and water are mixed according to a preset mass ratio; and the stirring speed is adjusted according to the near-infrared pre-monitoring result after the dynamic threshold evaluation in the step S1: If the hydroxyl characteristic peak intensity is less than the calibrated hydroxyl threshold value, the stirring speed is adaptively increased and the reaction time is extended. If the total impurity characteristic peak intensity is greater than the calibrated impurity threshold value, the stirring speed is adaptively reduced and the reaction time is extended.

[0012] Preferably, the near-infrared and Raman spectrum fusion monitoring process in the reaction stage in the step S3 includes the following steps: the intensity ratio of the characteristic peak of the compound containing an imidazole group and the characteristic peak of the corresponding cobalt salt product is captured according to the near-infrared spectrum, and the O-H vibration peak of water and the scattering peak of the undissolved raw material are captured according to the Raman spectrum; wherein: If the compound containing an imidazole group is imidazole, the characteristic peak wave number thereof is 2950 cm -1 , and the characteristic peak wave number of the corresponding imidazole cobalt product is 1575 cm -1 . If the compound containing an imidazole group is 2-methylimidazole, the characteristic peak wave number thereof is 2920 cm -1 , and the characteristic peak wave number of the corresponding 2-methylimidazole cobalt product is 1580 cm -1 . If the compound containing an imidazole group is benzimidazole, the characteristic peak wave number thereof is 2910 cm -1The characteristic peak wavenumber of the cobalt benzimidazole product is 1585 cm⁻¹. -1 ; If the total intensity of the impurity characteristic peaks in step S1 is greater than the calibrated impurity threshold, then the characteristic peak ratio threshold at the reaction endpoint will be adjusted from the initial preset characteristic peak ratio threshold to the adaptively adjusted characteristic peak ratio threshold.

[0013] Preferably, the automatic interference signal removal process in step S3 includes: The system has a built-in interference signal database and compares near-infrared and Raman spectral data in real time. If the intensity fluctuation of the near-infrared characteristic peak exceeds the preset fluctuation range, and the Raman spectrum shows that the intensity change of the OH peak of water exceeds the preset change range, then the near-infrared data set is removed, and the characteristic peak ratio is recalculated based on the Raman-corrected near-infrared signal to ensure the accuracy of reaction progress determination.

[0014] Preferably, the dual verification process in the drying stage of step S3 includes: The moisture content of the product was monitored using an online moisture meter, and the characteristic peaks of cobalt crystals containing imidazole groups were captured by Raman spectroscopy. When the moisture content meets the preset drying endpoint requirements, but the intensity of the crystal characteristic peaks does not meet the preset crystal integrity requirements, the drying time is automatically extended and the drying temperature is adjusted to a suitable value until the intensity of the crystal characteristic peaks reaches the preset crystal integrity requirements, ensuring the integrity of the product's crystal structure.

[0015] An application of a cobalt salt adhesion promoter, wherein the cobalt salt adhesion promoter obtained by the preparation process is applied to the bonding system between rubber and substrate.

[0016] The technical effects and advantages of this invention are as follows: (1) This invention solves the problems of inaccurate assessment of the activation degree (hydroxyl activity) of different batches of cobalt hydroxide and insufficient removal of impurities by combining near-infrared pre-monitoring with dynamic threshold judgment logic and differentiated secondary activation and secondary spraying strategies. It achieves the effect of consistent basic cobalt hydroxide reactivity after pretreatment and achieves the core goal of avoiding the impact of raw material quality fluctuations on subsequent processes from the source. (2) By constructing a stable and consistent raw material reactivity basis, this invention solves the problems of large fluctuations in coordination reaction rate, product yield and cobalt content in traditional processes, and achieves the effect of controllable coordination reaction process and stable core performance indicators (cobalt content and crystal structure) of product, thus meeting the key industrial production requirement of highly consistent product quality for each batch. (3) By ensuring the consistency of product quality, this invention solves the problem that the cobalt compound containing imidazole group has large fluctuations in adhesive performance and is difficult to adapt to the needs of high-end rubber products. It achieves the effect of excellent initial adhesive strength between rubber and substrates such as steel cord and carbon fiber, and meets the core application requirements of stable and reliable adhesive durability after thermo-oxidative aging and salt water aging under high load and high torque conditions of new energy vehicle tires. Attached Figure Description

[0017] Fig. 1 This is a schematic block diagram of the preparation process of the present invention; Fig. 2 These are colloidal rheological curves obtained from different embodiments; Fig. 3 The images show the scorch curves of the colloidal particles obtained in different embodiments. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0019] This invention provides, for example Figs. 1-3 The preparation process of a cobalt salt adhesion promoter shown is characterized by comprising the following steps: S1. After activating and drying cobalt hydroxide, impurities are removed by spraying with dilute hydrochloric acid and turning the material over. At the same time, the characteristic indicators of activated cobalt hydroxide are evaluated by near-infrared monitoring combined with dynamic threshold to output calibration parameters for subsequent process control. S2. The pretreated cobalt hydroxide and the compound containing imidazole groups are mixed in an aqueous medium and stirred at room temperature and pressure to obtain a blue-purple slurry. S3. In the reaction stage, near-infrared and Raman spectroscopy are used to monitor the reaction progress and automatically remove interference signals. In the drying stage, the product moisture and crystal structure are verified twice. At the same time, the reaction and drying parameters are dynamically calibrated based on the near-infrared pre-monitoring results after dynamic threshold evaluation in step S1. S4. Wash and dry the blue-purple slurry to obtain cobalt salt adhesive enhancer containing imidazole group compound cobalt.

[0020] By integrating raw material pretreatment, coordination reaction, online monitoring closed-loop control, and post-treatment into a complete process chain, and incorporating near-infrared pre-monitoring dynamic threshold judgment logic into the pretreatment, and employing a near-infrared-Raman dual-spectrum fusion and drying dual verification mechanism in the monitoring stage, this approach solves the problems of scattered control, lack of parameter linkage, and uncontrollable quality throughout the traditional cobalt preparation process containing imidazole groups. It achieves precise connection and data interoperability among all process stages, realizing closed-loop control of the entire chain from raw material quality screening to product performance assurance. This not only improves process stability but also ensures batch consistency of the core performance of cobalt salt binder, providing reliable process support for large-scale industrial production.

[0021] The activation and drying conditions in step S1 are: vacuum drying at 50-80℃ for 2-3 hours; after the dilute hydrochloric acid spraying in step S1, the following inert protection and rapid dehydration process for cobalt hydroxide is also included: S11. Collect basic information on cobalt hydroxide to be pretreated: including the initial particle size of cobalt hydroxide (range 3-10 μm), and determine the calibration basis based on historical data (including the correlation records of different raw material characteristics and subsequent coordination reaction activity and product purity); S12. Set the baseline threshold: Initial baseline hydroxyl characteristic peak (wavenumber 3620cm⁻¹) -1 The intensity threshold is 0.8, and the initial reference impurity characteristic peak (calcium characteristic peak wavenumber 4220 cm⁻¹) is... -1 Magnesium characteristic peak wavenumber 4510cm -1 The total intensity threshold is 0.3; S13. Dynamic calibration threshold: The baseline threshold is adaptively adjusted based on basic information and historical data. If the initial particle size of the cobalt hydroxide to be treated is 3-5 μm (smaller particle size, larger specific surface area, and easier to meet hydroxyl activity standards), the hydroxyl characteristic peak intensity threshold is lowered to 0.76-0.79; if the initial particle size is 5-10 μm (larger particle size, and easier to be insufficient in hydroxyl activity), the hydroxyl characteristic peak intensity threshold is raised to 0.81-0.84; if historical data shows that the average impurity intensity of the batch of cobalt hydroxide to be treated is ≤0.3 (stable impurity control), the total impurity characteristic peak intensity threshold is kept at 0.3; if historical data shows that the average impurity intensity of this type of batch is >0.3 (impurities are easy to exceed the standard), the total impurity characteristic peak intensity threshold is lowered to 0.27-0.29. S14. Threshold Verification: If it is a new characteristic batch without corresponding historical data, pre-monitoring should be performed according to the initial baseline threshold. If the subsequent coordination reaction activity is ≥90% (with the baseline activity as 100%) and the product purity is ≥98% after pre-monitoring, the data of this batch will be entered into the historical data as the calibration basis for subsequent raw materials of the same type. If the reaction activity is <90% or the purity is <98%, the initial baseline hydroxyl threshold will be lowered by 0.02 or the impurity threshold will be lowered by 0.02, and pre-monitoring will be repeated until the performance requirements are met.

[0022] By collecting characteristic parameters of cobalt hydroxide raw materials, setting benchmark thresholds based on historical records and dynamically adjusting them, and combining this with threshold verification and data supplementation mechanisms for new types of raw material batches, the problems of fixed and rigid quality evaluation standards, inability to adapt to differences in activation levels and impurity content in different batches of raw materials in traditional pretreatment processes have been solved. This has achieved a more precise and flexible effect in raw material quality evaluation, enabling targeted control of the hydroxyl activity and calcium and magnesium impurity content of cobalt hydroxide. This avoids over-processing of high-quality raw materials and prevents the misjudgment and release of inferior raw materials. At the same time, it improves the process's adaptability to raw materials from different sources and with different characteristics, laying a stable and consistent raw material foundation for subsequent coordination reactions, thereby improving the overall process's fault tolerance and adaptability.

[0023] In step S1, the impurity removal process involving dilute hydrochloric acid spraying combined with material tumbling is divided into three stages and is achieved using a single set of adjustable nozzles. Specifically, it includes: Stage 1 (0-8 min): dilute hydrochloric acid concentration 0.03 mol / L, spraying rate 3-5 mL / min, nozzle angle 30°, material turning speed 10-15 r / min, preferentially remove calcium impurities from the surface of cobalt hydroxide; Stage 2 (8-25 min): Dilute hydrochloric acid concentration 0.05 mol / L, spraying rate 8-10 mL / min, nozzle angle 60°, material turning speed 10-15 r / min, to permeate and remove magnesium impurities inside cobalt hydroxide agglomerates; Phase 3 (25-30 min): Dilute hydrochloric acid concentration 0.03 mol / L, spray rate 2-3 mL / min, nozzle angle 30°, material turning speed 5-8 r / min, to rinse off residual high-concentration acid solution.

[0024] By employing a single set of adjustable nozzles and setting differentiated dilute hydrochloric acid concentration, spray rate, nozzle angle, and material tumbling speed in three stages, this method solves the problems of traditional dilute hydrochloric acid spraying for impurity removal, such as single parameters, difficulty in penetrating and removing impurities inside cobalt hydroxide agglomerates, incomplete cleaning of residual acid on the surface, easy clogging of complex spraying structures, and high maintenance costs. It achieves the effect of efficient stratified removal of impurities without complex equipment, realizing targeted removal of calcium and magnesium impurities, preferential removal of easily soluble calcium impurities on the surface, and precise penetration and removal of insoluble magnesium impurities inside. At the same time, it avoids excessive corrosion of the hydroxyl groups on the surface of cobalt hydroxide by high-concentration acid, improving the purity of raw materials while protecting their subsequent coordination reaction activity, thus balancing the impurity removal effect and the protection of raw material performance.

[0025] After the dilute hydrochloric acid spraying in step S1 is completed, the process also includes the following inert protection and rapid dehydration treatment of cobalt hydroxide: a) Inert atmosphere replacement: The filtration area containing the sprayed cobalt hydroxide material is replaced with inert gas at least three times to ensure that the oxygen content in the area is lower than the preset low oxygen threshold (e.g., ≤100ppm). b) Gradient vacuum filtration under inert atmosphere: Under the condition of maintaining an inert atmosphere, vacuum filtration is carried out using a gradient vacuum degree to achieve solid-liquid separation. In the initial stage, a lower vacuum degree (e.g., 0.02-0.05 MPa) is used to avoid material loss due to violent boiling or splashing. After the material is initially compacted, the vacuum degree is gradually increased to the target vacuum degree (e.g., 0.08-0.1 MPa) to improve the solid-liquid separation efficiency and filter cake dryness. c) Rapid material transfer without exposure and segmented vacuum drying: After filtration, the filter cake is rapidly transferred to the drying area without disrupting the inert atmosphere (e.g., through a closed screw conveyor or a transfer channel protected by inert gas). The drying process employs a segmented heating strategy: initially, drying is carried out at a lower temperature (e.g., 40-60℃) for 20-40 minutes to quickly remove free water from the filter cake; later, the temperature is raised to a slightly higher temperature (e.g., 60-80℃) for 40-80 minutes to deeply remove bound water. During the drying process, a small amount of inert gas (e.g., nitrogen, at a flow rate of 0.5-2L / min) is continuously introduced to remove the volatile moisture and maintain a low-oxygen environment. d) Real-time monitoring and endpoint protection: During the drying process, the moisture content of the material is monitored in real time using an online moisture meter, while the oxidation rate (Co) is monitored using infrared spectroscopy or electrochemical methods. 3+ (Percentage); when the moisture content is ≤1% and the oxidation rate is ≤1% (meeting the requirements of subsequent coordination reactions), drying is stopped; the material is cooled to room temperature (e.g., ≤30℃) under inert gas protection to avoid oxidation and deterioration due to contact with air during subsequent transfer or storage, ensuring that cobalt hydroxide has stable and high reactivity in subsequent coordination reactions.

[0026] By sequentially performing inert atmosphere replacement, gradient vacuum filtration, rapid material transfer without exposure, segmented vacuum drying, and real-time monitoring of moisture content and oxidation rate in a continuous closed system, this method solves the problems of easy oxidation of cobalt hydroxide upon contact with air, secondary pollution during material transfer, uneven moisture content control, and low drying efficiency in traditional dehydration processes. It achieves a synergistic effect of low-oxygen protection of raw materials and rapid and efficient dehydration, effectively suppressing the oxidation rate of cobalt hydroxide and precisely controlling the moisture content. This avoids the decrease in reactivity caused by the oxidation of cobalt ions and ensures uniform moisture content of the raw materials. At the same time, the continuous processing flow reduces the time loss of intermediate links, improves the production efficiency of the pretreatment stage, and provides a key guarantee for the stability of subsequent coordination reactions.

[0027] In step S1, if the near-infrared pre-monitoring result does not meet the threshold after dynamic calibration, the following parameter compensation and adjustment process is also included: If the intensity of the hydroxyl characteristic peak is less than the calibrated hydroxyl threshold (insufficient activation): send cobalt hydroxide back into the activation and drying equipment and vacuum dry it at 80-90℃ for 1-1.5h for secondary activation. After secondary activation, perform near-infrared pre-monitoring again according to the dynamic threshold evaluation logic until the intensity of the hydroxyl characteristic peak is greater than or equal to the calibrated hydroxyl threshold. If the total intensity of the impurity characteristic peaks is greater than the calibrated impurity threshold (impurities exceed the standard): perform a second dilute hydrochloric acid spray on cobalt hydroxide. The second spray uses 0.04 mol / L dilute hydrochloric acid, with a spray rate of 5-7 mL / min, a nozzle angle of 45°, a material turning speed of 12-14 r / min, and a spray time of 10-15 min. After the second spray, perform near-infrared pre-monitoring again according to the dynamic threshold evaluation logic until the total intensity of the impurity characteristic peaks is less than or equal to the calibrated impurity threshold.

[0028] By addressing issues such as substandard hydroxyl activity and excessive impurity content in near-infrared pre-monitoring, a targeted parameter compensation and adjustment strategy involving secondary activation and secondary dilute hydrochloric acid spraying was adopted. This strategy resolved the problems of lacking effective remedial measures for raw material quality defects in traditional pretreatment processes, and the influx of substandard raw materials into subsequent processes leading to reaction failure or product scrap. It achieved precise correction of raw material quality defects, ensuring that each batch of cobalt hydroxide met the quality requirements of subsequent coordination reactions. This not only reduced production cost waste caused by substandard raw materials but also significantly improved the overall yield of the preparation process. Furthermore, it avoided interference from substandard raw materials to the reaction system, ensuring the stable progress of subsequent processes.

[0029] The material proportioning process for the coordination reaction in step S2 includes: 1.7 kg of a compound containing an imidazole group, 0.93 kg of pretreated cobalt hydroxide, and 5 L of water; the stirring speed was adjusted based on the near-infrared pre-monitoring results after dynamic threshold evaluation in step S1. If the intensity of the hydroxyl characteristic peak is less than the calibrated hydroxyl threshold (which is met after secondary activation), increase the stirring speed to 350-400 r / min and extend the reaction time to 1.2-1.5 h; If the total intensity of the impurity characteristic peaks is greater than the calibrated impurity threshold (which meets the standard after two sprays), the stirring speed is reduced to 250-300 r / min and the reaction time is extended to 1.5-2 h.

[0030] By precisely adjusting the proportions of imidazole-containing compounds, cobalt hydroxide, and water according to the appropriate ratio for coordination reactions, and dynamically adjusting the stirring speed and reaction time based on the near-infrared pre-monitoring results of raw material pretreatment, the problems of rigid fixed parameters in traditional coordination reactions, inability to adapt to differences in raw material quality, and incomplete or excessive reactions have been solved. This achieves a precise match between reaction parameters and raw material characteristics, enabling efficient and complete coordination reactions. When the raw material activity is insufficient, increasing the stirring speed and extending the time ensures complete reaction; when the raw material impurities are high, decreasing the stirring speed and extending the time avoids side reactions. This not only improves product yield and purity but also reduces by-product formation, lowering the difficulty and cost of subsequent separation and purification.

[0031] The near-infrared and Raman spectroscopy fusion monitoring process in step S3 includes: capturing the intensity ratio of the characteristic peaks of the imidazole-containing compound and the corresponding cobalt salt product based on near-infrared spectroscopy, and capturing the OH vibration peak of water and the scattering peaks of undissolved raw materials using Raman spectroscopy; wherein: If the compound containing the imidazole group is imidazole, its characteristic peak wavenumber is 2950 cm⁻¹. -1 The characteristic peak wavenumber of the corresponding imidazole cobalt product is 1575 cm⁻¹. -1 ; If the compound containing the imidazole group is 2-methylimidazole, its characteristic peak wavenumber is 2920 cm⁻¹. -1 The characteristic peak wavenumber corresponding to the 2-methylimidazolium cobalt product is 1580 cm⁻¹. -1 ; If the compound containing the imidazole group is benzimidazole, its characteristic peak wavenumber is 2910 cm⁻¹. -1 The characteristic peak wavenumber of the cobalt benzimidazole product is 1585 cm⁻¹. -1 ; If the total intensity of the impurity characteristic peaks in step S1 is greater than the calibrated impurity threshold, then the characteristic peak ratio threshold at the reaction endpoint will be adjusted from the initial preset characteristic peak ratio threshold to the adaptively adjusted characteristic peak ratio threshold.

[0032] This solution addresses the issue of inaccurate target peaks in spectroscopic monitoring after raw material expansion, avoiding confusion of characteristic peaks due to structural differences among different imidazole raw materials. It ensures the specificity and accuracy of reaction progress monitoring, preventing incomplete or excessive reactions caused by peak misjudgment. Continuing the logic of adjusting the endpoint characteristic peak ratio threshold when impurities exceed limits, it can still adapt to the residual impurities in raw materials through strict threshold adjustments, even considering the coordination reaction characteristics of different imidazole raw materials with cobalt hydroxide. This ensures that even if trace impurities remain after pretreatment, product purity can be controlled through precise threshold adjustments, preventing impurities from affecting coordination reaction efficiency and product performance.

[0033] The automatic interference signal removal process in step S3 includes: a) Construct and dynamically update the interference signal database: This database not only collects typical interference spectral characteristics under different process conditions (such as water volume fluctuation, undissolved raw material residue, temperature fluctuation, instrument drift, etc.), but also automatically learns and adds newly discovered, unrecognized interference patterns in each run. b) Multi-dimensional real-time signal comparison and correlation analysis: Real-time acquisition of near-infrared spectral data and Raman spectral data. The system not only compares whether the intensity fluctuation of near-infrared characteristic peaks exceeds the preset fluctuation range and whether the intensity change of the characteristic vibration peak of water in the Raman spectrum exceeds the preset change range, but also analyzes whether the preset correlation between the target peaks in the near-infrared signal (such as the characteristic peaks of compounds containing imidazole groups and the characteristic peaks of cobalt compounds containing imidazole groups) and the related peaks in the Raman signal (such as peaks reflecting the physical state of the reaction system) is destroyed. c) Intelligent judgment and data labeling: When any of the above preset conditions are detected to be met (such as intensity fluctuation exceeding the limit or correlation destruction), the system determines that the current near-infrared data is significantly interfered with and automatically labels the near-infrared data of that group or period as to be corrected or invalid. d) Adaptive correction model based on Raman signal: For labeled data, the system calls the built-in multivariate correction model. This model uses the characteristic information in the Raman spectrum that is not affected by the same interference or whose affected behavior is known (such as solvent peaks, internal standard peaks or other stable peaks related to the reaction process) to perform accurate mathematical correction or reconstruction on the interfered near-infrared signal, so as to restore the true, undisturbed near-infrared characteristic peak intensity information. e) Signal quality assessment and feedback after correction: After correction, the system will assess the quality of the corrected near-infrared signal. Only when the signal quality meets the preset confidence level requirements will the corrected signal replace the original interfered signal, and the characteristic peak ratio will be recalculated based on this. If the correction effect is not good, the system can issue an alarm or trigger a backup monitoring strategy to ensure the most reliable data input for reaction progress determination and subsequent closed-loop control parameter adjustment.

[0034] By constructing a dynamically updated interference signal database, conducting multi-dimensional spectral signal comparison and correlation analysis, and combining it with an adaptive correction model and a post-correction signal quality assessment mechanism, the problems of difficult effective identification of interference signals, single correction methods, and potential data distortion after correction in traditional spectral monitoring are solved. This achieves the effect of accurate correction and controllable quality of monitoring signals, realizes high reliability of near-infrared monitoring data, can identify and accurately eliminate known interference, and can learn new interference modes to avoid the erroneous elimination of valid data. At the same time, the effectiveness of the corrected data is ensured through quality assessment, providing accurate data support for reaction progress determination and closed-loop control parameter adjustment, and significantly reducing the risk of misadjustment of process parameters due to signal distortion.

[0035] The dual verification process in step S3, the drying stage, includes: The moisture content of the product was monitored using an online moisture meter (accuracy ±0.05%), and the characteristic peaks of cobalt crystals containing imidazole groups (wavenumber 1120 cm⁻¹) were captured by Raman spectroscopy. -1 ); When the moisture content is ≤0.5% but the crystal characteristic peak intensity is <0.9, the drying time is automatically extended by 5-10 minutes, and the drying temperature is reduced from 80℃ to 70℃ until the crystal characteristic peak intensity is ≥0.9, to ensure the integrity of the product's crystal structure and improve the stability of subsequent bonding performance.

[0036] By using an online moisture meter to monitor the product moisture content during the drying stage and simultaneously capturing the intensity of crystal characteristic peaks through Raman spectroscopy, the drying time and temperature are dynamically adjusted based on the integrity of the crystal structure. This solves the problem of traditional drying processes that only focus on moisture content while neglecting the integrity of the product's crystal structure, leading to crystal defects and affecting subsequent bonding performance. It achieves dual quality control in the drying process, ensuring that both the product's moisture content and crystal structure meet the standards. This guarantees that the product's moisture content meets storage and application requirements while ensuring the integrity and uniformity of the crystal structure, avoiding problems such as crystal agglomeration and defects caused by improper drying. Consequently, it ensures that the cobalt salt adhesive enhancer can stably exert excellent bonding performance in the subsequent rubber-substrate bonding system, improving the reliability during application.

[0037] An application of a cobalt salt adhesion promoter involves applying a cobalt salt adhesion promoter (i.e., a cobalt compound containing an imidazole group) obtained through a preparation process to an adhesive system between rubber and a substrate.

[0038] In addition, to verify the adhesive properties of the cobalt compound containing imidazole groups prepared in this application, a gradient experiment was designed, and conventional compounding methods in the art were used for compounding (the methods and process conditions were exactly the same in each embodiment). The formulations of each embodiment are shown in the table below:

[0039] The tested rubber vulcanization characteristics are shown in the table below:

[0040] The tested Mooney scorch characteristics of the rubber are shown in the table below:

[0041] The test results for the rubber adhesion strength are shown in the table below:

[0042] The imidazole-containing cobalt compound obtained in this application improves the initial and thermo-oxidative aging adhesion performance (T-pull) of the belt layer formulation by 10-20% compared with the traditional cobalt salt (cobalt borate) as an adhesion promoter.

[0043] 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 preparation process for a cobalt salt adhesion promoter, characterized in that, Includes the following steps: S1. After activating and drying cobalt hydroxide, impurities are removed by spraying with dilute hydrochloric acid and turning the material over. At the same time, the characteristic indicators of activated cobalt hydroxide are evaluated by near-infrared monitoring combined with dynamic threshold to output calibration parameters for subsequent process control. S2. The pretreated cobalt hydroxide and the compound containing imidazole groups are mixed in an aqueous medium and stirred at room temperature and pressure to obtain a blue-purple slurry. S3. In the reaction stage, near-infrared and Raman spectroscopy are used to monitor the reaction progress and automatically remove interference signals. In the drying stage, the product moisture and crystal structure are verified twice. At the same time, the reaction and drying parameters are dynamically calibrated based on the near-infrared pre-monitoring results after dynamic threshold evaluation in step S1. S4. The blue-purple slurry is washed and dried to obtain a cobalt salt adhesive enhancer containing an imidazole group.

2. The preparation process of the cobalt salt adhesion promoter according to claim 1, characterized in that, The dynamic threshold evaluation process for near-infrared pre-monitoring in step S1 includes: S11. Collect the raw material characteristic parameters of the cobalt hydroxide to be processed. The raw material characteristic parameters include its physical morphology parameters or source information. S12. Set the initial threshold values ​​for the intensity of the reference hydroxyl characteristic peak and the total intensity threshold values ​​for the reference impurity characteristic peak; S13. Based on the raw material characteristic parameters and by querying a historical database containing the correlation between raw material characteristic parameters and reaction activity and product purity, adaptively adjust the threshold values ​​for the baseline hydroxyl characteristic peak intensity and the total intensity threshold values ​​for the baseline impurity characteristic peak. S14. For raw material batches without corresponding data in the historical database, pre-monitoring is performed based on the benchmark threshold or the calibrated threshold, and the validity of the threshold is verified based on the results of subsequent coordination reactions. The verified valid threshold is then associated with the raw material characteristic parameters and updated to the historical database.

3. The preparation process of the cobalt salt adhesion promoter according to claim 1, characterized in that, The impurity removal process in step S1, which involves spraying dilute hydrochloric acid combined with material tumbling, is divided into three stages and is achieved using a single set of adjustable nozzles. Specifically, it includes: Phase 1: Using low-concentration dilute hydrochloric acid, low spray rate, first nozzle angle, first material tumbling speed, and continuous first preset time, calcium impurities on the surface of cobalt hydroxide are preferentially removed. Phase 2: Using medium-concentration dilute hydrochloric acid, high spray rate, second nozzle angle, and second material tumbling speed, for a second preset time, magnesium impurities inside the cobalt hydroxide agglomerates are removed through penetration. Phase 3: Using low-concentration dilute hydrochloric acid, low spray rate, first nozzle angle, third material tumbling speed, and a third preset time, rinse the residual high-concentration acid solution.

4. The preparation process of the cobalt salt adhesion promoter according to claim 1, characterized in that, After the dilute hydrochloric acid spraying in step S1 is completed, the following inert protection and rapid dehydration process for cobalt hydroxide is also included: After spraying, cobalt hydroxide is placed in an inert gas atmosphere and vacuum filtration is performed with a suitable vacuum level to achieve solid-liquid separation. After separation, it is immediately vacuum dried at a suitable temperature for a suitable time to control the water content and oxidation rate of cobalt hydroxide to meet the requirements of subsequent coordination reactions.

5. The preparation process of a cobalt salt adhesion promoter according to claim 2, characterized in that, If the near-infrared pre-monitoring result in step S1 does not meet the threshold after dynamic calibration, the following parameter compensation and adjustment process is also included: If the intensity of the hydroxyl characteristic peak is less than the calibrated hydroxyl threshold: send the cobalt hydroxide back into the activation and drying equipment, vacuum dry it for a suitable time at a suitable temperature for secondary activation, and then re-activate it according to the dynamic threshold evaluation logic for near-infrared pre-monitoring until the intensity of the hydroxyl characteristic peak is greater than or equal to the calibrated hydroxyl threshold. If the total intensity of the impurity characteristic peaks is greater than the calibrated impurity threshold: perform a second dilute hydrochloric acid spray on cobalt hydroxide. The second spray uses an appropriate concentration of dilute hydrochloric acid, an appropriate spray rate, a third nozzle angle, a fourth material tumbling speed, and lasts for a fourth preset time. After the second spray, perform near-infrared pre-monitoring again according to the dynamic threshold evaluation logic until the total intensity of the impurity characteristic peaks is less than or equal to the calibrated impurity threshold.

6. The preparation process of the cobalt salt adhesion promoter according to claim 5, characterized in that, The material proportioning process for the coordination reaction in step S2 includes: Compounds containing imidazole groups, pretreated cobalt hydroxide, and water are mixed at a preset mass ratio; the stirring speed is adjusted based on the near-infrared pre-monitoring results after dynamic threshold evaluation in step S1. If the intensity of the hydroxyl characteristic peak is less than the calibrated hydroxyl threshold, then the stirring speed should be increased and the reaction time extended accordingly. If the total intensity of the impurity characteristic peaks is greater than the calibrated impurity threshold, the stirring speed should be reduced and the reaction time extended accordingly.

7. The preparation process of a cobalt salt adhesion promoter according to claim 2, characterized in that, The near-infrared and Raman spectroscopy fusion monitoring process in step S3 includes: capturing the intensity ratio of the characteristic peaks of the imidazole-containing compound and the corresponding cobalt salt product based on near-infrared spectroscopy, and capturing the OH vibration peak of water and the scattering peaks of undissolved raw materials using Raman spectroscopy; wherein: If the compound containing the imidazole group is imidazole, its characteristic peak wavenumber is 2950 cm⁻¹. -1 The characteristic peak wavenumber of the corresponding imidazole cobalt product is 1575 cm⁻¹. -1 ; If the compound containing the imidazole group is 2-methylimidazole, its characteristic peak wavenumber is 2920 cm⁻¹. -1 The characteristic peak wavenumber corresponding to the 2-methylimidazolium cobalt product is 1580 cm⁻¹. -1 ; If the compound containing the imidazole group is benzimidazole, its characteristic peak wavenumber is 2910 cm⁻¹. -1 The characteristic peak wavenumber of the cobalt benzimidazole product is 1585 cm⁻¹. -1 ; If the total intensity of the impurity characteristic peaks in step S1 is greater than the calibrated impurity threshold, then the characteristic peak ratio threshold at the reaction endpoint will be adjusted from the initial preset characteristic peak ratio threshold to the adaptively adjusted characteristic peak ratio threshold.

8. The preparation process of the cobalt salt adhesion promoter according to claim 1, characterized in that, The automatic interference signal removal process in step S3 includes: The system has a built-in interference signal database and compares near-infrared and Raman spectral data in real time. If the intensity fluctuation of the near-infrared characteristic peak exceeds the preset fluctuation range, and the Raman spectrum shows that the intensity change of the OH peak of water exceeds the preset change range, then the near-infrared data set is removed, and the characteristic peak ratio is recalculated based on the Raman-corrected near-infrared signal.

9. The preparation process of a cobalt salt adhesion promoter according to claim 1, characterized in that, The dual verification process in the drying stage of step S3 includes: The moisture content of the product was monitored using an online moisture meter, and the characteristic peaks of cobalt crystals containing imidazole groups were captured by Raman spectroscopy. When the moisture content meets the preset drying endpoint requirements, but the intensity of the crystal characteristic peaks does not meet the preset crystal integrity requirements, the drying time is automatically extended and the drying temperature is adjusted to a suitable value until the intensity of the crystal characteristic peaks reaches the preset crystal integrity requirements.

10. The application of a cobalt salt adhesive enhancer, characterized in that, The cobalt salt adhesive enhancer obtained by any of the preparation processes described in claims 1-9 is applied to the adhesive system between rubber and substrate.

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