A method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors.

Abstract

This invention relates to the field of hot melt adhesive preparation technology, and more particularly to a method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors. The method includes determining the corresponding raw material type by obtaining the hydroxyl value index and isocyanate group index, thereby calculating the hydroxyl value deviation or isocyanate group deviation to determine the catalyst dosage adjustment range or the initial reaction temperature adjustment range; determining the reaction time for prepolymerization based on the adjusted catalyst dosage and initial reaction temperature; calculating the reaction uniformity and absorption peak intensity decay rate by real-time monitoring of the characteristic absorption peak intensity during the reaction; comparing the reaction uniformity with a preset reaction uniformity to determine whether to perform acceleration adjustment; and comparing the absorption peak intensity decay rate with a preset absorption peak decay rate to determine whether to extend the reaction time, ultimately preparing the hot melt adhesive. This invention effectively overcomes raw material batch fluctuations and process disturbances, significantly improving the consistency and overall performance of the hot melt adhesive.

Description

Technical Field

[0001] This invention relates to the field of hot melt adhesive technology, and in particular to a method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors. Background Technology

[0002] Hot melt adhesives, as an environmentally friendly adhesive, are widely used in electronics, automotive manufacturing, and packaging materials. Among them, insulating, heat-resistant, and flame-retardant hot melt adhesives used in mechanical motors not only need excellent bonding performance but also need to meet special requirements such as high temperature resistance, flame retardancy, and insulation. Their performance directly affects the operational safety and lifespan of the motor. Currently, high-performance hot melt adhesives for motors mostly adopt polyurethane systems, forming a cross-linked network through the reaction of polyol components with isocyanates, endowing the adhesive with excellent mechanical and heat resistance properties. The preparation process of this type of hot melt adhesive involves complex chemical reactions; for example, the hydroxyl value of the polyol and the isocyanate group content of the isocyanate can directly affect the reaction stoichiometry, cross-linking density, and final product performance.

[0003] Chinese patent application publication number CN101255327A discloses a method for preparing a moisture-curing reactive polyurethane hot melt adhesive for footwear. The related technical solution involves mixing hydroxyl-terminated liquid rubber and polyether diol, heating to remove moisture, cooling, adding toluene diisocyanate dropwise and reacting, then adding trimethylolpropane, tackifying resin, and catalyst while stirring. The reaction is stopped when the isocyanate group content is detected to be 6%–8% and the viscosity is 800–1000 centipoise, followed by degassing, discharging, and sealing in packaging. This method controls reaction termination by detecting the isocyanate group content and viscosity at the reaction endpoint, and can prepare a polyurethane hot melt adhesive with good adhesive properties. However, the above solution still has the following problems: The relevant technical solutions use fixed formulas and fixed process parameters for preparation, without detecting and compensating for batch fluctuations in raw materials; offline testing is only performed after the reaction is completed, making it impossible to monitor key state indicators such as mixing uniformity and reaction rate in real time during the reaction. This easily leads to high sensitivity of product quality to raw material fluctuations and poor batch consistency; there is a lack of feedback control means to dynamically adjust process parameters based on process deviations, making it impossible to adjust parameters such as stirring speed, reaction temperature, and reaction time in real time during the reaction, and making it difficult to ensure that each batch of product completes the reaction under optimal process conditions.

[0004] Therefore, there is an urgent need for an intelligent control method that can sense fluctuations in raw material characteristics, monitor the reaction status in real time during the reaction process, and dynamically adjust process parameters according to process deviations, in order to solve the problem of inconsistent product quality caused by batch fluctuations in raw materials and lack of process control in the existing technology. Summary of the Invention

[0005] Therefore, the present invention provides a method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors, in order to overcome the problems of poor product quality consistency caused by the inability to perceive raw material batch fluctuations, the lack of real-time monitoring of the reaction process, and the inability to dynamically adjust process parameters in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors, comprising: Obtain the hydroxyl value index of the polyol component and the isocyanate group index of the isocyanate; The corresponding raw material type is determined based on the hydroxyl value index and the isocyanate group index, respectively, and the corresponding preset index thresholds. Based on the type of raw material, determine the corresponding deviation threshold, and based on the hydroxyl value deviation and the hydroxyl value deviation threshold, determine whether to adjust the catalyst dosage or based on the isocyanate group deviation and the isocyanate group deviation threshold, determine whether to adjust the initial reaction temperature. If it is determined that the amount of catalyst to be adjusted should be adjusted, the adjustment range of the amount of catalyst should be determined based on the difference between the hydroxyl value deviation and the hydroxyl value deviation threshold. If it is determined that the initial reaction temperature should be adjusted, the adjustment range of the initial reaction temperature is determined based on the difference between the isocyanate group deviation degree and the isocyanate group deviation threshold degree. The corresponding reaction time is determined based on the catalyst dosage and the initial reaction temperature to carry out the prepolymerization reaction; The absorption peak intensity of the isocyanate group characteristic wavenumber was determined based on several near-infrared spectral data of the mixture in the prepolymerization reaction, so as to construct the absorption peak intensity sequence within a preset time window and determine the corresponding reaction uniformity. Whether to perform speed-up adjustment is determined based on the reaction uniformity and the preset reaction uniformity, and whether to adjust the reaction time is determined based on the absorption peak intensity decay rate and the preset absorption peak decay rate.

[0007] Furthermore, the amount of catalyst is increased based on the comparison results of the hydroxyl value deviation being greater than or equal to the hydroxyl value deviation threshold. The initial reaction temperature is increased based on the comparison results where the isocyanate group deviation is greater than or equal to the isocyanate group deviation threshold. The preset index threshold includes a preset hydroxyl value index and a preset isocyanate group index. The hydroxyl value deviation is obtained by processing the hydroxyl value index and the preset hydroxyl value index, and the isocyanate group deviation is obtained by processing the isocyanate group index and the preset isocyanate group index.

[0008] Furthermore, the increase in the amount of catalyst is determined based on the difference between the hydroxyl value deviation and the hydroxyl value deviation threshold; The increase in the initial reaction temperature is determined based on the difference between the isocyanate group deviation and the isocyanate group deviation threshold.

[0009] Furthermore, the process of determining the corresponding reaction uniformity includes: The near-infrared spectral data of the mixture are collected in real time based on a fixed sampling frequency, and the absorption peak intensities corresponding to the characteristic wavenumbers of the isocyanate groups in several near-infrared spectral data are extracted, and an absorption peak intensity sequence within a preset time window is constructed. The reaction uniformity is determined based on the standard deviation of the absorption peak intensity sequence.

[0010] Furthermore, the process of determining whether to perform growth rate adjustment includes: The speed increase adjustment is determined based on the comparison result that the reaction uniformity is greater than or equal to the preset reaction uniformity.

[0011] Furthermore, the process of determining the execution of the growth rate adjustment includes: The growth rate of the growth rate adjustment is determined based on the uniformity deviation, and the growth rate is positively correlated with the uniformity deviation. The uniformity deviation is determined based on the difference between the reaction uniformity and the preset reaction uniformity.

[0012] Furthermore, the process of determining whether to adjust the reaction time includes: The reaction time is adjusted based on the comparison results of the absorption peak intensity decay rate being less than the preset absorption peak decay rate.

[0013] Furthermore, the process of determining the adjustment of the reaction time includes: The extension of the reaction time is determined based on the difference in the decay rate, and the extension is positively correlated with the difference in the decay rate. The decay rate difference is determined based on the difference between the decay rate of the preset absorption peak and the decay rate of the absorption peak intensity.

[0014] Furthermore, the process of determining the corresponding raw material type includes: Based on the comparison results of the hydroxyl value index being greater than or equal to the preset hydroxyl value index and the isocyanate group index being less than the preset isocyanate group index, the raw material type is determined to be high hydroxyl value type. Based on the comparison results of the hydroxyl value index being less than the preset hydroxyl value index and the isocyanate group index being greater than or equal to the preset isocyanate group index, the raw material type is determined to be high isocyanate group type. Based on the comparison results of the hydroxyl value index being greater than or equal to the preset hydroxyl value index and the isocyanate group index being greater than or equal to the preset isocyanate group index, the raw material type is determined to be a dual-abnormal raw material. Based on the comparison results of the hydroxyl value index being less than the preset hydroxyl value index and the isocyanate group index being less than the preset isocyanate group index, the raw material type is determined to be a standard raw material.

[0015] Furthermore, the insulating, heat-resistant, and flame-retardant hot melt adhesive is prepared from the following raw materials in parts by weight, wherein, The polyol component includes 5-15 parts of polyether polyol, 8-12 parts of first polyester polyol, 5-10 parts of second polyester polyol, 5-8 parts of first polycarbonate polyol, 5-10 parts of second polycarbonate polyol, and 5-10 parts of polycarbonate polyether polyol. 20 to 30 parts of the isocyanate, and 0.5 to 1 part of the catalyst.

[0016] Compared with existing technologies, the beneficial effects of the preparation method of the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors of the present invention are as follows: The batch-to-batch variation of raw materials is quantified by detecting hydroxyl value and isocyanate group content; the hydroxyl value index and isocyanate group index are compared with preset hydroxyl value index and preset isocyanate group index, respectively, to determine the raw material type; then, a corresponding deviation threshold is determined based on the raw material type; and based on the comparison result of hydroxyl value deviation and hydroxyl value deviation threshold, it is determined whether to adjust the catalyst dosage, or based on the comparison result of isocyanate group deviation and isocyanate group deviation threshold, it is determined whether to adjust the initial reaction temperature, thereby actively adjusting the catalyst dosage and the initial reaction temperature. Temperature is used to compensate for the impact of raw material fluctuations on the reaction process from the source, avoiding uneven crosslinking networks caused by raw material differences. Subsequently, a prepolymerization reaction is carried out according to the adjusted catalyst dosage and initial reaction temperature, and near-infrared spectral data is collected to extract the absorption peak intensity at the characteristic wavenumber of isocyanate groups. An absorption peak intensity sequence within the time window is constructed, and the reaction uniformity is calculated. The reaction uniformity is compared with the preset reaction uniformity to determine whether to implement speed-up adjustment. Simultaneously, the absorption peak intensity decay rate is compared with the preset decay rate to determine whether to adjust the reaction time, thereby ensuring that the reaction always proceeds under optimal conditions. Finally, degassing is performed to obtain the product. This invention achieves compensation for raw material fluctuations and correction of preparation process deviations through multi-parameter synergistic optimization, significantly improving the batch stability and consistency of hot melt adhesive quality.

[0017] Furthermore, this invention obtains hydroxyl value deviation and isocyanate group deviation by processing the hydroxyl value index and a preset hydroxyl value index, and the isocyanate group index and a preset isocyanate group index, respectively, to eliminate the influence of dimensions; and determines the increase in catalyst dosage based on the hydroxyl value deviation and the hydroxyl value deviation threshold, and determines the increase in initial reaction temperature based on the isocyanate group deviation and the isocyanate group deviation threshold; thereby realizing a quantitative control mechanism, accurately compensating for batch fluctuations of raw materials, avoiding reaction runaway caused by ignoring raw material differences, and preventing new problems caused by overcompensation, thus ensuring that each batch of reaction starts under optimal initial conditions.

[0018] Furthermore, this invention also acquires near-infrared spectra at a fixed sampling frequency, extracts the intensity of characteristic wavenumber absorption peaks, constructs an intensity sequence within a time window, and calculates the standard deviation to obtain the reaction uniformity. When the reaction uniformity is greater than or equal to a preset reaction uniformity threshold, an acceleration is initiated; otherwise, it is not. The magnitude of the acceleration adjustment is determined based on the uniformity deviation. This achieves precise perception and control of the mixing state, ensuring that the acceleration is only initiated when the mixing is truly uneven, avoiding ineffective adjustment, and thus maintaining the reaction process in a uniform mixing state, providing a prerequisite for the full progress of subsequent cross-linking reactions.

[0019] Furthermore, this invention extends the reaction time only when the absorption peak intensity decay rate is less than a preset decay rate threshold, and does not extend it otherwise. The extension of the reaction time is determined based on the difference between the preset decay rate and the measured decay rate. This achieves closed-loop control of the reaction process, avoiding reaction lag due to raw material fluctuations or process disturbances. It also ensures sufficient cross-linking by dynamically extending the reaction time, thereby avoiding performance defects caused by incomplete reaction. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating a method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to an embodiment of the present invention. Figure 2 This is a logic decision diagram for determining the corresponding raw material type in an embodiment of the present invention; Figure 3 This is a logic diagram for determining whether to adjust the catalyst dosage or the initial reaction temperature in an embodiment of the present invention. Figure 4 This is a logic diagram for determining whether to perform speed-up adjustment and whether to adjust the response time in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0024] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Please see Figure 1 The diagram shown is a flowchart of a method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to an embodiment of the present invention. The preparation method includes at least the following: S1: Obtain the hydroxyl value index of the polyol component and the isocyanate group index of the isocyanate; S2: Determine the corresponding raw material type based on the hydroxyl value index and isocyanate group index, respectively, and the corresponding preset index thresholds; S3: Determine the corresponding deviation threshold based on the type of raw materials, and determine whether to adjust the amount of catalyst based on the hydroxyl value deviation and the hydroxyl value deviation threshold, or determine whether to adjust the initial reaction temperature based on the isocyanate group deviation and the isocyanate group deviation threshold. S4: To determine the amount of catalyst to be adjusted, the adjustment range of the catalyst amount is determined based on the difference between the hydroxyl value deviation and the hydroxyl value deviation threshold. S5: If the initial reaction temperature is to be adjusted, the adjustment range of the initial reaction temperature is determined based on the difference between the isocyanate group deviation degree and the isocyanate group deviation degree threshold. S6: Determine the corresponding reaction time based on the catalyst dosage and initial reaction temperature to carry out the prepolymerization reaction; S7: Determine the absorption peak intensity of the characteristic wavenumber of the isocyanate group based on several near-infrared spectral data of the mixture in the prepolymerization reaction, so as to construct the absorption peak intensity sequence within the preset time window and determine the corresponding reaction uniformity. S8: Determine whether to perform speed-up adjustment based on reaction uniformity and preset reaction uniformity, and determine whether to adjust reaction time based on absorption peak intensity decay rate and preset absorption peak decay rate; S9: After the prepolymerization reaction is completed, the mixture is degassed to obtain an insulating, heat-resistant, and flame-retardant hot melt adhesive.

[0026] In the preparation of moisture-curing polyurethane hot melt adhesives, the hydroxyl groups in the polyol component undergo a stepwise addition polymerization reaction with the isocyanate groups in the isocyanate to form urethane bonds and a cross-linked network. The extent, rate, and final cross-linking density of the reaction directly determine the adhesive strength, heat resistance, flame retardancy, and insulation properties of the adhesive. The hydroxyl value of the polyol reflects the concentration of hydroxyl groups; the higher the hydroxyl value, the more hydroxyl groups are provided per unit mass of polyol, the more isocyanate is required, and the higher the reactivity. The isocyanate group content of the isocyanate determines the number of active groups participating in the reaction. Therefore, the hydroxyl value and isocyanate group content of the raw materials are key parameters affecting reaction stoichiometry and product performance.

[0027] In actual production, slight fluctuations in hydroxyl value and isocyanate group content are inevitable between different batches of polyols and isocyanates. If a fixed catalyst dosage and reaction temperature are used, a high hydroxyl value may lead to an excessively rapid reaction, over-crosslinking, or even gelation; a low hydroxyl value may result in incomplete reaction and insufficient crosslinking. Similarly, a high isocyanate group content will make the system too rigid and brittle, while a low content will result in insufficient reactivity and slow curing. Therefore, it is necessary to determine the degree of deviation between the hydroxyl value and isocyanate group content of the raw materials and the corresponding standard contents, and to compensate for raw material fluctuations at the source, ensuring that the reaction of each batch proceeds under optimal conditions.

[0028] The hydroxyl value of the polyol components was determined to obtain the hydroxyl index OH, expressed in mgKOH / g, using an industry-standard titration method. The isocyanate content of the isocyanates was determined to obtain the isocyanate group index NCO, expressed as a percentage by mass (%), using an industry-standard di-n-butylamine method.

[0029] Please see Figure 2The diagram shown illustrates the logic for determining the corresponding raw material type in this embodiment of the invention. The detected hydroxyl value index (OH) is compared with a preset hydroxyl value index (OHth), and the isocyanate group index (NCO) is compared with a preset isocyanate group index (NCOth). The corresponding raw material type is determined based on the comparison results. The preset hydroxyl value index threshold (OHth) and the preset isocyanate group index threshold (NCOth) are determined statistically based on historical production data of qualified batches. Specifically, batches with excellent overall performance of the final product are selected from the historical database of the production management system, and the corresponding polyol hydroxyl value data set and isocyanate group content data set are extracted. The arithmetic mean of the two data sets is calculated and used as the benchmark value for the preset threshold. For example, if the average polyol hydroxyl value is 56 mgKOH / g, then OHth is set to 56; if the average isocyanate group content is 6.5%, then NCOth is set to 6.5%.

[0030] Specifically, if OH≥OHth and NCO<NCOth, it indicates that the polyol activity is too high, while the isocyanate group content is normal or too low. It is necessary to increase the amount of catalyst to balance the reaction rate and prevent the reaction from being too fast due to the high hydroxyl value. At the same time, the catalyst can also promote the reaction to compensate for the slight deficiency of NCO. Therefore, the raw material type is set to high hydroxyl value type. If OH < OHth and NCO ≥ NCOth, it indicates that the isocyanate group content is too high, while the polyol activity is normal or too low. It is necessary to increase the initial reaction temperature to increase the reaction activity and promote the full reaction of NCO. In this case, the raw material type is set to high isocyanate group type. If OH≥OHth and NCO≥NCOth, it indicates that both values ​​are too high, and it is necessary to increase the amount of catalyst and the initial reaction temperature at the same time. The raw material type should be set as a double-abnormal raw material. If OH < OHth and NCO < NCOth, it indicates that both values ​​are within the normal range and no adjustment is needed. The raw material type should be set to standard.

[0031] It is understandable that any batch of materials will have normal random fluctuations. The deviation can be calculated and the result of comparing the deviation with the deviation threshold can be used to determine whether to implement an adjustment plan. The adjustment procedure will only be initiated when the deviation exceeds the deviation threshold. In actual production, the impact mechanism of abnormal patterns of different raw materials on the reaction is different. Therefore, it is necessary to set different deviation thresholds for different abnormality types and adopt differentiated adjustment strategies.

[0032] In this example, to quantify the degree of deviation of raw materials from the standard, hydroxyl value deviation ΔOH and isocyanate group deviation ΔNCO are defined, and corresponding deviation thresholds are set for different raw material types: high hydroxyl value type corresponds to the hydroxyl value deviation threshold ΔOHth, high isocyanate group type corresponds to the isocyanate group deviation threshold ΔNCOth, and dual-abnormality type uses both of the above thresholds. For high hydroxyl value types, the hydroxyl value index OH exceeds the preset hydroxyl value index OHth, and the hydroxyl value deviation ΔOH needs to be calculated. The specific calculation formula is: ΔOH=(OH-OHth) / OHth. At the same time, the isocyanate group index NCO is lower than NCOth, and there is no need to adjust the temperature. Therefore, the isocyanate group deviation ΔNCO=0. For high isocyanate group type, the isocyanate group index NCO exceeds NCOth, and the isocyanate group deviation ΔNCO needs to be calculated. The specific calculation formula is: ΔNCO=(NCO-NCOth) / NCOth. At the same time, the hydroxyl value index OH is lower than OHth, which does not constitute a need to adjust the amount of catalyst. Therefore, the hydroxyl value deviation ΔOH=0. For the dual-abnormal type, ΔOH and ΔNCO need to be calculated simultaneously. The calculation formula for ΔOH is the same as that for the high hydroxyl type, and the calculation formula for ΔNCO is the same as that for the high isocyanate group type.

[0033] For standard raw materials, there is no deviation that needs to be compensated, therefore ΔOH=0, ΔNCO=0.

[0034] The deviation threshold is determined based on statistical analysis of historical production data. Specifically, the method involves filtering all high-hydroxyl-value production records from the historical database of the production management system, extracting the corresponding hydroxyl-value deviation data sets, and statistically analyzing the product pass rate within different ΔOH intervals. The critical point at which the pass rate begins to significantly decrease is set as the hydroxyl-value deviation threshold ΔOHth. For example, if statistics show that the product pass rate remains above 95% when ΔOH ≤ 0.03, then ΔOHth = 0.03 is set.

[0035] Similarly, production records for all high isocyanate groups are filtered from the historical database, and the corresponding high isocyanate group deviation data sets are extracted. The product pass rate within different ΔNCO ranges is then calculated. The critical point at which the pass rate begins to decrease significantly is set as the isocyanate group deviation threshold ΔNCOth. For example, when ΔNCO ≤ 0.04, the product pass rate remains above 95%, so ΔNCOth = 0.04 is set.

[0036] For the double-abnormality type, the deviation thresholds for ΔOH and ΔNCO are the same as those for ΔOHth and ΔNCOth mentioned above, respectively; For standard applications that do not involve deviation thresholds.

[0037] Understandably, by detecting the hydroxyl value of the polyol components and the isocyanate group content of the isocyanate, the batch fluctuations of the raw materials were quantified. Based on the test results, the catalyst dosage and initial reaction temperature were adjusted to improve the formation quality of the polyurethane crosslinking network. When the hydroxyl value is too high, the amount of catalyst should be increased appropriately to promote the full reaction between the hydroxyl group and the isocyanate group, improve the conversion rate of the isocyanate group, and avoid insufficient crosslinking density due to incomplete reaction. The uniform distribution of crosslinking density directly improves the heat resistance (increased heat distortion temperature) and insulation (increased volume resistivity) of the hot melt adhesive, while preventing unreacted groups from absorbing moisture or degrading during long-term use, thus ensuring the long-term stability of insulation performance.

[0038] When the isocyanate group content is too high, the initial reaction temperature should be appropriately increased to enhance reaction activity and promote the full participation of excess isocyanate groups in crosslinking, thus avoiding the residue of free isocyanate groups. Residual isocyanate groups may react with moisture during subsequent use to form urea groups, disrupting the uniformity of the colloidal structure and leading to decreased insulation performance and reduced heat resistance.

[0039] For high-performance raw materials, the catalyst and temperature are adjusted simultaneously to improve the formation of the cross-linked network structure, providing a stable matrix environment for the uniform dispersion of flame retardants, thereby giving full play to the synergistic effect of flame retardants and ensuring the reliability of flame retardant performance.

[0040] Please see Figure 3 The diagram shown illustrates the logic for determining whether to adjust the catalyst dosage or the initial reaction temperature in an embodiment of the present invention. Based on the raw material type and the calculated deviation, combined with the corresponding deviation threshold, the system determines whether to adjust the catalyst dosage or the initial reaction temperature, and the corresponding adjustment range.

[0041] For high hydroxyl value catalysts, if ΔOH ≥ ΔOHth, then the catalyst dosage C needs to be increased. The increase in catalyst dosage C, ΔC, is determined based on the difference between ΔOH and ΔOHth, and the calculation formula is: ΔC = kC·(ΔOH - ΔOHth), where kC is the catalyst adjustment coefficient, with units of "parts / unit deviation". This coefficient is pre-calibrated based on equipment response characteristics and process requirements, and can be obtained as kC = 0.5 through regression analysis of historical data. If ΔOH < ΔOHth, then the catalyst dosage C is not adjusted.

[0042] For high isocyanate group type, if ΔNCO≥ΔNCOth, it is determined that the initial reaction temperature T0 needs to be increased. The increase in the initial reaction temperature T0 ΔT is determined based on the difference between ΔNCO and ΔNCOth, and the calculation formula is: ΔT=kT·(ΔNCO-ΔNCOth), where kT is the temperature adjustment coefficient, and the unit is "℃ / unit deviation". Through experimental calibration, kT can be set to 5 for example. If ΔNCO < ΔNCOth, then the initial reaction temperature T0 is not adjusted.

[0043] For the double anomaly type, the comparisons are performed as described above. If ΔOH ≥ ΔOHth, ΔC is determined based on the difference between ΔOH and ΔOHth, with the specific formula being: ΔC = kC·(ΔOH - ΔOHth); if ΔNCO ≥ ΔNCOth, ΔT is determined based on the difference between ΔNCO and ΔNCOth, with the specific formula being: ΔT = kT·(ΔNCO - ΔNCOth). For the standard model, no feedforward adjustment is performed; preset values ​​for catalyst dosage C0 and initial reaction temperature T0 are used. These preset values ​​are determined based on historically optimal process parameters. Specifically, the method involves selecting batches with excellent overall final product performance from the historical database of the production management system, and extracting the corresponding catalyst dosage and initial reaction temperature data sets. The arithmetic mean of the two data sets is calculated and used as the preset baseline value. For example, if the average catalyst dosage is 0.8 parts, then C0 is set to 0.8 parts; if the average initial reaction temperature is 85℃, then T0 is set to 85℃.

[0044] In one specific embodiment, the prepolymerization reaction is carried out in a reactor equipped with stirring, heating and vacuum devices by setting the reaction time according to the adjusted catalyst dosage C (C=C0+ΔC) and reaction temperature T (T=T0+ΔT).

[0045] Specifically, polyol components (including polyether polyols, polyester polyols, polycarbonate polyols, etc.) are added to the reactor according to the formula, heated to a set temperature (e.g., 80°C), isocyanate is added, and the corresponding catalyst dosage C is added. The reaction is carried out under stirring, with the reaction temperature controlled at the corresponding temperature T. Based on the raw material type determination, the adjusted catalyst dosage C, and the reaction temperature T, the corresponding initial reaction time t0 is determined. The initial reaction time t0 is a standard reaction time determined based on historical production data. From the historical database of the production management system, batches using standard processes and with excellent final product performance are selected. The actual reaction time data set of these batches is extracted, and the arithmetic mean of the reaction time data set is calculated as the initial reaction time. For example, t0 is set to 120 minutes.

[0046] It is understandable that increasing the catalyst dosage or raising the temperature will accelerate the reaction rate. Therefore, the reaction time needs to be shortened accordingly to ensure the consistency of the reaction degree. The reaction time t is determined based on historical data statistical analysis, and an empirical relationship model is established between the catalyst dosage correction coefficient C0 / C and the temperature correction coefficient T0 / T and the reaction time. For example, the product form is used for estimation, and the specific formula for calculating the reaction time t is: t = t0·C0 / C·T0 / T, where C0 / C is the catalyst dosage correction coefficient and T0 / T is the initial reaction temperature correction coefficient.

[0047] For the standard type, the initial reaction time is used directly, i.e., t=t0.

[0048] For high hydroxyl value type where only the amount of catalyst C is adjusted, the reaction time is: t = t0·C0 / (C0+ΔC). For the high isocyanate group type where only the initial reaction temperature is adjusted, the reaction time is corrected as: t = t0·T0 / (T0 + ΔT); For the double-abnormal type, the reaction time is: t = t0·C0 / C·T0 / T.

[0049] In one specific embodiment, a near-infrared spectral probe mounted on the reactor is used to collect near-infrared spectral data of the mixture in real time at a fixed sampling frequency (once per minute). Near-infrared spectroscopy can reflect the absorption characteristics of specific chemical groups in a substance. Isocyanate groups (-NCO) have characteristic absorption peaks in the near-infrared spectral region. By performing spectral scanning on a pure isocyanate sample, the location of its maximum absorption peak is determined. Near this wavenumber, the absorption of polyols and other components is weak, which can be used as the quantitative characteristic wavenumber of the NCO group. Furthermore, from the near-infrared spectral data at each sampling time, [the following parameters can be extracted]. absorption peak intensity at According to Beer-Lambert's law, absorbance is directly proportional to the concentration of NCO groups, therefore... Changes in NCO concentration directly reflect changes in NCO concentration, i.e., the reaction progress; during the reaction, the uniformity of mixing directly affects the consistency of the reaction. If mixing is uneven, local NCO concentrations will fluctuate over time, leading to… It fluctuates. Therefore, through analysis... The degree of fluctuation within a short time window can be used to assess the uniformity of mixing.

[0050] In this embodiment, the sliding window method is used to continuously monitor the reaction uniformity in real time, and the absorption peak intensity is collected at a fixed sampling frequency f. For each new data point acquired, a window sequence is constructed by taking all sampling points within the time interval ΔΓ prior to that time. Specifically, a preset time window length ΔΓ (10 minutes) is set. At time Γ, the absorption peak intensity values ​​of all sampling points within the time interval ΔΓ prior to that time are taken to form a sequence. The sequence length is n = ΔΓ·f, where f is the sampling frequency (times / minute). The arithmetic mean and standard deviation U of the sequence are then calculated. U represents the uniformity of the reaction at time Γ, and the standard deviation U reflects the dispersion of the data relative to the mean. When the mixture is uniform, the difference in NCO concentration measured at different times is small. When the mixture is stable, the standard deviation is small; when the mixture is uneven, the concentration of NCO groups fluctuates greatly, resulting in a larger standard deviation.

[0051] It is understandable that the reaction uniformity and decay rate in the prepolymerization reaction directly characterize the mixing uniformity and reaction degree during the reaction process: When the reaction uniformity exceeds the standard, speed adjustment is implemented to enhance shear and turbulence, promoting the uniform dispersion of flame retardants in the polyurethane matrix. If flame retardants agglomerate, the local concentration may be too high or too low, potentially leading to localized failure during combustion. By adjusting the speed, the flame retardant achieves uniform distribution in the early stages of the reaction, fully maximizing its flame-retardant effect.

[0052] When the decay rate is too low, the reaction time is extended to ensure that the isocyanate groups are fully consumed and the reaction degree reaches the target, thereby improving the cross-linking network and enhancing the heat resistance (increased heat distortion temperature) and mechanical properties (increased peel strength) of the hot melt adhesive. At the same time, the improved cross-linking network can better fix the flame retardant, preventing it from migrating or precipitating at high temperatures and ensuring the durability of the flame retardant performance.

[0053] Through real-time monitoring and feedback control, the entire reaction process is always maintained in an optimal state, avoiding microstructural defects caused by uneven local mixing or incomplete reaction. By obtaining a more uniform and dense cross-linked network structure, the insulation, heat resistance and flame retardant properties of the hot melt adhesive remain highly consistent between batches.

[0054] Please see Figure 4 As shown, this is a logic diagram for determining whether to perform speed-up adjustment and whether to adjust the reaction time in an embodiment of the present invention. Specifically, the calculated reaction uniformity Ut is compared with the preset reaction uniformity Uth, and the initial stirring speed R0 is adjusted based on the comparison result. The preset reaction uniformity threshold Uth is determined based on statistical data from historical qualified batches. Specifically, batches that meet final product performance standards and exhibit good mixing during the reaction process are selected from the historical database. The reaction uniformity data set of these batches during the stable reaction phase is extracted, and their 95th percentile is calculated as Uth. For example, Uth is set to 0.05.

[0055] The initial stirring speed R0 is determined based on historical production data. Specifically, it involves selecting batches with excellent final product performance from the historical database of the production management system, extracting the stirring speed data set of these batches at the initial stage of the reaction, and calculating their arithmetic mean as the initial stirring speed. For example, R0 can be set to 200 revolutions per minute.

[0056] If Ut ≥ Uth, then a speed increase adjustment is required. The magnitude of the speed increase adjustment, ΔR, is determined based on the uniformity deviation, and the specific calculation formula is: ΔR = kR·(Ut - Uth), where kR is the speed adjustment coefficient, and the unit is "revolutions per minute per standard deviation". This coefficient is pre-calibrated through the equipment response characteristics. For example, in the experiment, it was determined that increasing the speed by 100 revolutions per minute can reduce the standard deviation by approximately 0.01, so kR can be set to 100.

[0057] If Ut < Uth, then the speed increase adjustment is not performed, and the stirring speed is maintained at R0.

[0058] In this embodiment, the absorption peak intensity gradually decreases over time, reflecting the rate at which NCO groups are consumed. The decay rate of the absorption peak intensity within a preset time window length ΔΓ is then calculated using the following formula: ,in, The absorption peak intensity is at the beginning of the window. The intensity is given by ΔΓ, where ΔΓ is the time window, and Rt is the absorption peak intensity decay rate at the current moment. A positive value indicates a decrease. The unit is: .

[0059] Understandably, Rt represents the rate of NCO group consumption at the current moment, directly reflecting the kinetic state of the chemical reaction. A larger Rt indicates a faster NCO group consumption rate and a more vigorous reaction, potentially due to factors such as sufficient catalyst, suitable reaction temperature, and high reactant activity. Conversely, a smaller Rt indicates a slower NCO group consumption rate and a more sluggish reaction, possibly due to insufficient catalyst, low reaction temperature, low reactant activity, or the reaction being nearing completion with a very low NCO concentration.

[0060] Specifically, the comparison between the absorption peak intensity decay rate Rt and the preset absorption peak decay rate Rth determines whether to adjust the reaction time. The preset decay rate threshold Rth is determined based on historical qualified batch data. Specifically, it involves selecting batches from a historical database that have normal reaction processes and qualified final product performance, extracting their decay rate data in the later stages of the reaction, and calculating their average value as Rth. For example, a specific setting can be provided. .

[0061] If Rt < Rth, then the reaction time needs to be extended. The extension amount ΔRt is determined based on the difference between Rth and Rt, specifically using the formula: ΔRt = α·(Rth - Rt), where α is the time adjustment coefficient, measured in minutes per unit rate. α is determined through process experience; for example, for every minute the rate is lower than the required adjustment amount, the adjustment factor is α. If the reaction needs to be extended by 30 minutes, then set α=30 minutes.

[0062] If Rt≥Rth, then the reaction time is not extended.

[0063] In one specific embodiment, after the prepolymerization reaction is completed, the mixture is degassed. Degasting is typically performed for 30 minutes under vacuum conditions <0.67 kPa and a temperature of 80–90°C to remove bubbles generated during the reaction and avoid affecting the colloidal properties. After degasing, the material is discharged to obtain an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical and electrical applications.

[0064] In this embodiment, the polyol component includes polyether polyol, first polyester polyol, second polyester polyol, first polycarbonate polyol, second polycarbonate polyol, and polycarbonate polyether polyol, wherein, The average molecular weight of the polyether polyol is 4000-6500, and the functionality is 3. The first polyester polyol has an average molecular weight of 4000-5000 and a functionality of 2. The second polyester polyol has an average molecular weight of 2500-3000 and a functionality of 2. The first polycarbonate polyol has an average molecular weight of 1500-3000 and a functionality of 2. The average molecular weight of the second polycarbonate polyol is 3500-6000, and its functionality is 2. The average molecular weight of polycarbonate polyether polyol is 3000-5500, and the functionality is 3. An insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical and electrical applications is prepared from the following raw materials in parts by weight: The composition includes 5-15 parts of polyether polyol, 8-12 parts of the first polyester polyol, 5-10 parts of the second polyester polyol, 5-8 parts of the first polycarbonate polyol, 5-10 parts of the second polycarbonate polyol, 5-10 parts of polycarbonate polyether polyol, 20-30 parts of isocyanate (such as TDI, MDI, etc.), and 0.5-1 part of catalyst (such as organotin, tertiary amine).

[0065] In this embodiment, the following raw materials are also included in parts by weight, wherein, The epoxy resin (liquid epoxy resin, epoxy equivalent 100-150 eq / 100g) is 1-5 parts; The amount of polyacrylic acid resin (molecular weight 2000-5000) is 1-7 parts; The coupling agent (such as silane coupling agent or titanate coupling agent) is 0.5 to 3 parts; The cross-linking agent (such as trimethylolpropane) is 1 to 3 parts; The amount of flame retardant (such as at least two of the following: halogen-free phosphorus flame retardants, organophosphate flame retardants, or phosphorus-nitrogen intumescent flame retardants) is 1 to 12 parts.

[0066] Parts by weight is a dimensionless unit that expresses the relative mass ratio between components.

[0067] In other embodiments, flame retardants such as OP935, OP-550, and ExolitAP423 can be mixed in a 1:1:1 ratio to obtain a flame retardant and added as a raw material. The combination of multiple flame retardants can exert a synergistic effect, improve flame retardant efficiency, and meet the UL94 (flame retardant rating) V-0 level.

[0068] To better illustrate the manufacturing process of the present invention, the present invention will be further described below with reference to specific embodiments.

[0069] Example 1: Weigh the raw materials according to the following weight proportions: 10 parts polyether polyol, 10 parts first polyester polyol, 8 parts second polyester polyol, 6 parts first polycarbonate polyol, 8 parts second polycarbonate polyol, 8 parts polycarbonate polyether polyol, 2 parts epoxy resin, 5 parts polyacrylic acid resin, 25 parts isocyanate (TDI), 1.5 parts coupling agent, 0.8 parts catalyst (dibutyltin dilaurate), 2 parts crosslinking agent (trimethylolpropane), 8 parts flame retardant (halogen-free phosphorus flame retardant, organophosphate flame retardant and phosphorus-nitrogen intumescent flame retardant mixed in a 1:1:1 ratio); The hydroxyl value of the polyol mixture was determined to be OH = 55 mg KOH / g; the NCO content of the isocyanate was determined to be 6.3%.

[0070] Since OH < OHth and NCO < NCOth, the raw material type is determined to be standard. The catalyst dosage is set to the preset value of C0 = 0.8 parts, the initial reaction temperature is set to T0 = 85℃, and the initial reaction time is set to t0 = 120 minutes.

[0071] The prepolymerization reaction is carried out according to the selected parameters, with an initial stirring speed of R0 = 200 rpm.

[0072] During the reaction, the intensity of the characteristic absorption peak of NCO was monitored in real time using near-infrared spectroscopy. At 60 minutes of reaction, the absorption peak intensity sequence over the most recent 10 minutes was calculated, and the reaction uniformity was found to be Ut = 0.04 < Uth, indicating uniform mixing and no need for speed-up adjustment. At 110 minutes of reaction, the decay rate was calculated to be Rt = 0.052 > Rth, indicating a normal reaction rate and no need to extend the reaction time. The reaction was terminated at the initial reaction time t0 = 120 minutes, followed by 30 minutes of degassing, and then the product was discharged as hot melt adhesive.

[0073] Example 2: Weigh the raw materials according to the following weight proportions: 5 parts polyether polyol, 8 parts first polyester polyol, 5 parts second polyester polyol, 5 parts first polycarbonate polyol, 5 parts second polycarbonate polyol, 5 parts polycarbonate polyether polyol, 1 part epoxy resin, 1 part polyacrylic acid resin, 20 parts isocyanate (TDI), 0.5 parts coupling agent, 0.5 parts catalyst (dibutyltin dilaurate), 1 part crosslinking agent (trimethylolpropane), 5 parts flame retardant (halogen-free phosphorus flame retardant and organophosphate flame retardant mixed in a 1:1 ratio); The measured values ​​were OH = 58 mg KOH / g and NCO = 6.2%. Since OH ≥ OHth and NCO < NCOth, it was determined to be a high hydroxyl value type.

[0074] The calculated hydroxyl value deviation ΔOH≈0.0357>ΔOHth indicates that the catalyst dosage needs to be increased. The calculated catalyst increase ΔC=0.00285 parts, rounded to 0.003 parts, results in an actual catalyst dosage of C=0.803 parts, and the initial reaction temperature is T0=85℃.

[0075] The calculated reaction time is approximately 119.6 minutes.

[0076] After the reaction started, the initial stirring speed was 200 rpm, and the system continuously monitored Ut and Rt. At 50 minutes into the reaction, Ut = 0.06 > Uth, indicating the need to activate speed regulation. The calculated speed increase ΔR = 1 rpm was then set to increase the stirring speed to 201 rpm. The reaction concluded after 119.6 minutes, followed by degassing and discharge.

[0077] Example 3: Weigh the raw materials according to the following weight proportions: 15 parts polyether polyol, 12 parts first polyester polyol, 10 parts second polyester polyol, 8 parts first polycarbonate polyol, 10 parts second polycarbonate polyol, 10 parts polycarbonate polyether polyol, 5 parts epoxy resin, 7 parts polyacrylic acid resin, 30 parts isocyanate (TDI), 3 parts coupling agent, 1.0 part catalyst (dibutyltin dilaurate), 3 parts crosslinking agent (trimethylolpropane), 12 parts flame retardant (organophosphate flame retardant and phosphorus nitrogen intumescent flame retardant mixed in a 1:1 ratio); The measured OH concentration was 55 mg KOH / g, and NCO concentration was 6.8%, classifying it as a high isocyanate group type. The isocyanate group deviation ΔNCO = 0.0462 > ΔNCOth, indicating a need to increase the initial reaction temperature T0. The calculated ΔT = 0.031℃, which is taken as 0.03℃, resulting in an actual initial reaction temperature T = 85.03℃. The catalyst dosage was maintained at 0.8 parts. The calculated reaction time t ≈ 119.96 minutes.

[0078] After the reaction started, the initial stirring speed was 200 rpm, and the system was continuously monitored. At 115 minutes into the reaction, the calculated decay rate Rt = 0.043 < Rth, indicating a need to extend the initial reaction time. The calculated extension amount ΔRt = 0.21 minutes, and the reaction end time was adjusted to 120.15 minutes. After the reaction, the material was degassed and discharged.

[0079] In Comparative Example 4, the same raw materials as in Example 2 were used, but without raw material detection or feedforward adjustment. A fixed catalyst dosage C0 = 0.8 parts, a fixed initial reaction temperature T0 = 85°C, and a fixed reaction time t0 = 120 minutes were directly adopted. No online monitoring or feedback control was performed during the reaction.

[0080] Compared with Example 5, the same raw materials as in Example 2 were used, and complete feedforward control was performed (catalyst dosage was adjusted to 0.803 parts, reaction time was 119.6 minutes). However, near-infrared monitoring was not performed during the reaction, and no speed-up adjustment or reaction time extension was performed. The stirring speed was fixed at 200 rpm, and the reaction ended at the calculated time of 119.6 minutes.

[0081] In Comparative Example 6, the same raw materials as in Example 3 were used, and complete feedforward control was performed (temperature adjusted to 85.03℃, reaction time 119.96 minutes). Near-infrared monitoring was not performed during the reaction, the reaction time was not extended, the stirring speed was fixed at 200 rpm, and the reaction was completed in 120 minutes.

[0082] Performance testing and evaluation: The performance of the hot melt adhesives prepared in the above examples was tested, including: Peel strength (N / cm): Tested according to GB / T2791-1995, the sample is aluminum-aluminum bond, and the tensile speed is 100mm / min.

[0083] The sample thickness was 1 mm, and the test voltage was 500 V.

[0084] Flame retardancy rating: Tested according to UL94 standard, with a sample thickness of 1.6 mm, and rated as V-0, V-1 or V-2.

[0085] Heat distortion temperature (°C): Tested according to GB / T1634-2004, load 1.80MPa.

[0086] The test results are shown in Table 1.

[0087] Table 1 Performance test results of each embodiment and control example.

[0088] As shown in Table 1, Examples 1 to 3, which fully implement the method of this invention, achieve excellent overall performance regardless of whether they use standard or fluctuating raw materials, through feedforward control and process feedback. This demonstrates the adaptive capability of this invention to raw material fluctuations and process disturbances. Comparative Example 4 lacks feedforward control and fails to compensate for the excessively rapid reaction caused by a high hydroxyl value, resulting in incomplete reaction and decreased peel strength, flame retardancy rating, and heat distortion temperature. Comparative Example 5, although it includes feedforward compensation, lacks process feedback and fails to correct the uneven mixing during preparation, resulting in performance still lower than Example 2 with complete control. Comparative Example 6 only includes feedforward temperature compensation and lacks process feedback, failing to correct the excessively slow reaction rate, and its performance also declines. In summary, the method of this invention achieves precise compensation for batch fluctuations in raw materials through raw material characteristic detection and feedforward control. Through near-infrared spectroscopy online monitoring and real-time feedback control, it achieves dynamic optimization of mixing uniformity and reaction rate during the reaction process, significantly improving product consistency and overall performance.

[0089] All technologies not mentioned in the above embodiments are applicable to existing technologies. It is understood that no specific limitation is made to any preset parameter or critical parameter in the embodiments of the present invention, and the above values ​​are not limited thereto. Those skilled in the art can adjust the preset parameters or critical parameters accordingly based on actual needs, analysis of historical data, or equipment usage.

[0090] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing an insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors, characterized in that, include: Obtain the hydroxyl value index of the polyol component and the isocyanate group index of the isocyanate; The corresponding raw material type is determined based on the hydroxyl value index and the isocyanate group index, respectively, and the corresponding preset index thresholds. Based on the type of raw material, determine the corresponding deviation threshold, and based on the hydroxyl value deviation and the hydroxyl value deviation threshold, determine whether to adjust the catalyst dosage or based on the isocyanate group deviation and the isocyanate group deviation threshold, determine whether to adjust the initial reaction temperature. If it is determined that the amount of catalyst to be adjusted should be adjusted, the adjustment range of the amount of catalyst should be determined based on the difference between the hydroxyl value deviation and the hydroxyl value deviation threshold. If it is determined that the initial reaction temperature should be adjusted, the adjustment range of the initial reaction temperature is determined based on the difference between the isocyanate group deviation degree and the isocyanate group deviation threshold degree. The corresponding reaction time is determined based on the catalyst dosage and the initial reaction temperature to carry out the prepolymerization reaction; The absorption peak intensity of the isocyanate group characteristic wavenumber was determined based on several near-infrared spectral data of the mixture in the prepolymerization reaction, so as to construct the absorption peak intensity sequence within a preset time window and determine the corresponding reaction uniformity. Whether to perform speed-up adjustment is determined based on the reaction uniformity and the preset reaction uniformity, and whether to adjust the reaction time is determined based on the absorption peak intensity decay rate and the preset absorption peak decay rate.

2. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 1, characterized in that, The amount of catalyst is increased based on the comparison results where the hydroxyl value deviation is greater than or equal to the hydroxyl value deviation threshold. The initial reaction temperature is increased based on the comparison results where the isocyanate group deviation is greater than or equal to the isocyanate group deviation threshold. The preset index threshold includes a preset hydroxyl value index and a preset isocyanate group index. The hydroxyl value deviation is obtained by processing the hydroxyl value index and the preset hydroxyl value index, and the isocyanate group deviation is obtained by processing the isocyanate group index and the preset isocyanate group index.

3. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 2, characterized in that, The increase in the amount of catalyst is determined based on the difference between the hydroxyl value deviation and the hydroxyl value deviation threshold. The increase in the initial reaction temperature is determined based on the difference between the isocyanate group deviation and the isocyanate group deviation threshold.

4. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 1, characterized in that, The process of determining the corresponding reaction uniformity includes: The near-infrared spectral data of the mixture are collected in real time based on a fixed sampling frequency, and the absorption peak intensities corresponding to the characteristic wavenumbers of the isocyanate groups in several near-infrared spectral data are extracted, and an absorption peak intensity sequence within a preset time window is constructed. The reaction uniformity is determined based on the standard deviation of the absorption peak intensity sequence.

5. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 4, characterized in that, The process of determining whether to implement growth rate adjustment includes: The speed increase adjustment is determined based on the comparison result that the reaction uniformity is greater than or equal to the preset reaction uniformity.

6. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 5, characterized in that, The process of determining the execution speed adjustment includes: The growth rate of the growth rate adjustment is determined based on the uniformity deviation, and the growth rate is positively correlated with the uniformity deviation. The uniformity deviation is determined based on the difference between the reaction uniformity and the preset reaction uniformity.

7. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 1, characterized in that, The process of determining whether to adjust the reaction time includes: The reaction time is adjusted based on the comparison results of the absorption peak intensity decay rate being less than the preset absorption peak decay rate.

8. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 7, characterized in that, The process of determining the adjustment of the reaction time includes: The extension of the reaction time is determined based on the difference in the decay rate, and the extension is positively correlated with the difference in the decay rate. The decay rate difference is determined based on the difference between the decay rate of the preset absorption peak and the decay rate of the absorption peak intensity.

9. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 2, characterized in that, The process of determining the corresponding raw material type includes: Based on the comparison results of the hydroxyl value index being greater than or equal to the preset hydroxyl value index and the isocyanate group index being less than the preset isocyanate group index, the raw material type is determined to be high hydroxyl value type. Based on the comparison results of the hydroxyl value index being less than the preset hydroxyl value index and the isocyanate group index being greater than or equal to the preset isocyanate group index, the raw material type is determined to be high isocyanate group type. Based on the comparison results of the hydroxyl value index being greater than or equal to the preset hydroxyl value index and the isocyanate group index being greater than or equal to the preset isocyanate group index, the raw material type is determined to be a dual-abnormal raw material. Based on the comparison results of the hydroxyl value index being less than the preset hydroxyl value index and the isocyanate group index being less than the preset isocyanate group index, the raw material type is determined to be a standard raw material.

10. The method for preparing the insulating, heat-resistant, and flame-retardant hot melt adhesive for mechanical motors according to claim 1, characterized in that, The insulating, heat-resistant, and flame-retardant hot melt adhesive is prepared from the following raw materials in parts by weight: The polyol component includes 5-15 parts of polyether polyol, 8-12 parts of first polyester polyol, 5-10 parts of second polyester polyol, 5-8 parts of first polycarbonate polyol, 5-10 parts of second polycarbonate polyol, and 5-10 parts of polycarbonate polyether polyol. 20 to 30 parts of the isocyanate, and 0.5 to 1 part of the catalyst.

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