A quick detection method for quality of anti-yellowing agent product based on melting point apparatus

Abstract

The present application relates to the technical field of melting point detection, and in particular to a quick detection method for the quality of anti-yellowing agent products based on a melting point apparatus. The method comprises: using the melting point apparatus to quickly heat the anti-yellowing agent sample, collecting the furnace temperature sequence and the transmitted light intensity sequence during the heating process, calculating the instantaneous phase change factor at each moment according to the light intensity change rate and the reference light intensity, constructing a dynamic thermal hysteresis compensation model based on the instantaneous phase change factor to nonlinearly correct the furnace temperature, and inverting the real sample temperature sequence. The initial melting point and the full melting point of the anti-yellowing agent sample are determined through feature point recognition, and the product purity score is calculated in combination with the theoretical melting point. The method introduces a phase change endothermic feedback mechanism based on the light intensity change rate, effectively eliminates the dynamic thermal hysteresis error under high heating rate, and improves the timeliness and accuracy of the quality detection of anti-yellowing agent products.

Description

Technical Field

[0001] This invention relates to the field of melting point detection technology, and in particular to a rapid method for detecting the quality of anti-yellowing agents based on a melting point apparatus. Background Technology

[0002] HN-150, an anti-yellowing agent, is a key chemical additive whose purity directly determines the anti-yellowing performance of downstream polyurethane materials. Melting point and melting range are the most critical physical indicators for detecting its purity. HN-150 typically appears as a white crystalline powder and is highly sensitive to temperature changes. Currently, laboratories primarily use a capillary photoelectric melting point apparatus for testing. To ensure accuracy, standard operating procedures usually require heating at an extremely low rate near the melting point, relying on a photoelectric sensor to monitor changes in sample transmittance to determine the initial melting and full melting points, thereby assessing product quality.

[0003] However, existing detection technologies use slow heating, resulting in excessively long testing times, typically exceeding 15 minutes. This leads to extremely low testing efficiency, failing to meet the timeliness requirements of large-volume factory testing. To improve efficiency, if the heating rate is significantly increased, the sample temperature almost stagnates due to the dramatic endothermic phase transition that occurs when the anti-yellowing agent HN-150 melts, while the furnace sensor temperature continues to rise. This difference in physical properties causes the sensor temperature to be much higher than the actual sample temperature, resulting in severe thermal hysteresis. Existing linear correction methods cannot capture this nonlinear dynamic physical process, leading to significantly overestimation of the results from rapid detection.

[0004] Furthermore, since the samples are in powder form, the difference in the degree of compaction between different batches of samples will change their thermal conductivity, resulting in inconsistent thermal hysteresis characteristics, which are difficult to correct with a uniform standard constant. Although existing equipment attempts to correct the error by subtracting a fixed constant, linear correction methods are not very effective for substances like anti-yellowing agents that have obvious endothermic phase change characteristics.

[0005] Therefore, there is an urgent need for a method that can eliminate nonlinear thermal hysteresis errors at high heating rates and restore the true melting process in order to accurately test the product quality of anti-yellowing agents. Summary of the Invention

[0006] To address the problems of low detection efficiency due to low heating rates and inaccurate results due to severe thermal hysteresis caused by phase change endothermic reactions at high heating rates in the detection of anti-yellowing agents, this invention proposes a rapid detection method for anti-yellowing agent product quality based on a melting point apparatus, comprising:

[0007] The anti-yellowing agent sample was rapidly heated using a melting point apparatus. The furnace temperature and transmitted light intensity were collected at each moment during the heating process to obtain the furnace temperature sequence and transmitted light intensity sequence. Based on the transmitted light intensity sequence, the all-solid reference light intensity and the all-liquid reference light intensity were determined, and the rate of change of light intensity at each moment was calculated.

[0008] The instantaneous phase transition factor is calculated based on the light intensity change rate, the all-solid-state reference light intensity, and the all-liquid-state reference light intensity to characterize the heat absorption degree of the anti-yellowing agent sample.

[0009] A dynamic thermal hysteresis compensation model is constructed based on the instantaneous phase change factor. The furnace temperature at that moment is nonlinearly corrected using the dynamic thermal hysteresis compensation model to invert and restore the true sample temperature of the anti-yellowing agent sample at each moment, so as to obtain the true sample temperature sequence.

[0010] The initial melting point and total melting point of the anti-yellowing agent sample are determined by identifying feature points in the temperature sequence and transmitted light intensity sequence of the real sample.

[0011] The theoretical melting point of the anti-yellowing agent sample is obtained, and the product purity score is calculated based on the initial melting point, the total melting point, and the theoretical melting point, thereby achieving rapid detection of the anti-yellowing agent product quality.

[0012] This technical solution introduces a linkage analysis mechanism of light and heat. Traditional temperature correction often only considers the heating rate, providing a fixed correction value. However, at the critical moment of sample melting, due to the absorption of latent heat of phase change, the rate of heat absorption inside the sample changes drastically. A fixed correction value cannot cope with this dynamic change. By monitoring the rate of change of transmitted light intensity, the microscopic rhythm of sample melting is keenly captured. The faster the light intensity changes, the more intense the melting and the more heat absorbed. This characteristic is reflected by calculating the instantaneous phase change factor, allowing real-time sensing of the amount of heat absorbed by the sample. Furthermore, using a dynamic thermal hysteresis compensation model, the temperature compensation is automatically increased at the moment of most intense melting, while maintaining the basic compensation during non-melting periods. This dynamic correction restores the temperature that should exist due to heat absorption during melting from inflated furnace temperature data, restoring the true temperature of the sample during the melting process. Finally, the purity score of the sample is calculated based on the restored true temperature, improving the timeliness and accuracy of quality monitoring.

[0013] Preferably, after collecting the furnace temperature and transmitted light intensity at each moment during the heating process, the following preprocessing operation is also performed: a preset filtering window is set, and at each moment, the furnace temperature and transmitted light intensity at that moment are subjected to moving average filtering according to the filtering window to achieve smooth preprocessing of the furnace temperature and transmitted light intensity at that moment.

[0014] Preferably, the method for determining the all-solid reference light intensity and the all-liquid reference light intensity based on the transmitted light intensity sequence is as follows: the heating process is divided into an initial stage and a stable stage based on the transmitted light intensity sequence; the average value of the transmitted light intensity at all times in the initial stage is taken as the all-solid reference light intensity; and the average value of the transmitted light intensity at all times in the stable stage is taken as the all-liquid reference light intensity.

[0015] Preferably, the instantaneous phase transition factor is calculated based on the light intensity change rate, the all-solid-state reference light intensity, and the all-liquid-state reference light intensity, according to the following relationship:

[0016]

[0017] In the formula, for The instantaneous phase transition factor at time t, for The intensity of transmitted light at any given moment. As the all-solid-state reference light intensity, As the reference light intensity in the fully liquid state, This is a preset numerical stability constant used to prevent the denominator from being zero. These are preset weighting coefficients used to amplify the influence of the rate of change of light intensity. for Rate of change of light intensity over time It is the absolute value symbol.

[0018] This technical solution constructs an instantaneous phase transition factor, which not only focuses on the numerical value of the transmitted light intensity itself, but also introduces the dynamic index of the light intensity change rate. It can keenly capture the moment when melting is most intense and heat absorption is strongest. When the phase transition factor increases, it clearly indicates that the sample is currently in a state of high thermal resistance or intense heat absorption, providing a precise physical basis for subsequent nonlinear temperature compensation.

[0019] Preferably, the rate of change of light intensity is determined as follows: the transmitted light intensity at each moment is subtracted from the transmitted light intensity at the previous moment, and then divided by the time interval between the current moment and the previous moment to obtain the rate of change of light intensity at that moment.

[0020] Preferably, a dynamic thermal hysteresis compensation model is constructed based on the instantaneous phase change factor. This model is then used to nonlinearly correct the furnace temperature at that moment, thereby reconstructing the true sample temperature of the anti-yellowing agent sample at each moment. This process is based on the following relationship:

[0021]

[0022] In the formula, For the anti-yellowing agent sample in The actual sample temperature at any given time. for Furnace temperature at all times The heating rate for rapidly heating the anti-yellowing agent sample, This is the inherent fundamental lag time constant of the melting point apparatus. The preset basic thermal resistance constant, This is the preset phase change endothermic gain coefficient. for The instantaneous phase transition factor at a given moment.

[0023] This technical solution uses a dynamic thermal hysteresis compensation model to dynamically adjust the compensation intensity using an instantaneous phase change factor: basic linear compensation is performed in the non-melting region, and the compensation amount is greatly increased through nonlinear terms in the melting endothermic region. This approach can restore the physical melting process on the calculated real temperature curve, thereby offsetting the dynamic thermal hysteresis error caused by rapid heating, making the calculation results approximate the real physical state under slow heating.

[0024] Preferably, the initial melting point and total melting point of the anti-yellowing agent sample are determined by identifying feature points in the actual sample temperature sequence and the transmitted light intensity sequence, including:

[0025] In the transmitted light intensity sequence, the transmitted light intensity reaches At this point, the actual sample temperature corresponding to the first characteristic moment is recorded as the initial melting point, and the transmitted light intensity reaches [value missing]. At this point, the actual sample temperature corresponding to the second characteristic moment is recorded as the total melting point, where... As the all-solid-state reference light intensity, The reference light intensity is for the entire liquid state.

[0026] Preferably, the product purity score is calculated based on the initial melting point, the total melting point, and the theoretical melting point using the following formula:

[0027]

[0028] In the formula, Rate the product purity. The preset penalty coefficient, This refers to the temperature value of the full melting point. This is the temperature value of the initial melting point. The temperature value represents the theoretical standard melting point of the anti-yellowing agent sample. It is a logarithmic function.

[0029] This technical solution, by combining transmitted light intensity and corrected true temperature, can accurately pinpoint the initial melting point and the full melting point. It introduces a scoring formula that includes a natural logarithmic penalty term, which not only considers the melting range width but also applies a weighted penalty specifically for the high-temperature melting range. This comprehensive scoring mechanism can more objectively and sensitively reflect the actual quality of the anti-yellowing agent, realizing a fully automated closed loop from data acquisition to quality rating, and meeting the dual requirements of efficiency and precision in industrial settings.

[0030] Preferably, after calculating the product purity score, the method further includes: obtaining a preset quality grading threshold table, comparing the product purity score with the thresholds in the quality grading threshold table, determining the quality grade of the anti-yellowing agent sample, and outputting the result.

[0031] Preferably, the anti-yellowing agent sample is rapidly heated using a melting point apparatus, and the furnace temperature and transmitted light intensity are collected at each moment during the heating process. This includes: grinding the anti-yellowing agent sample and loading it into a capillary tube and compacting it; setting the heating rate of the melting point apparatus to 5.0℃ / min; and after starting the heating, using a photoelectric sensor to synchronously collect the furnace temperature and transmitted light intensity at each moment.

[0032] The present invention has the following effects:

[0033] This solution establishes a phase change endothermic feedback mechanism by introducing an instantaneous phase change factor based on the rate of change of light intensity and a dynamic thermal hysteresis compensation model. This mechanism can evaluate the endothermic intensity of the sample in real time and perform nonlinear temperature correction at high heating rates, accurately restoring the real melting process of the sample. This eliminates the dynamic thermal hysteresis error in rapid detection and improves the timeliness and accuracy of product quality control in industrial production sites. Attached Figure Description

[0034] Figure 1 This is a flowchart of the method of the present invention;

[0035] Figure 2 This is a graph showing the trend of transmitted light intensity during the melting process of the anti-yellowing agent in this invention;

[0036] Figure 3 This is a comparison chart of the temperature compensation effects of the present invention and existing technologies. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0038] This invention discloses a rapid testing method for the quality of anti-yellowing agents based on a melting point apparatus, referring to... Figure 1 This includes steps S1-S4:

[0039] S1: The anti-yellowing agent sample was rapidly heated using a melting point apparatus. The furnace temperature and transmitted light intensity were collected at each moment during the heating process to obtain the furnace temperature sequence and transmitted light intensity sequence, and then preprocessed.

[0040] First, grind the anti-yellowing agent HN-150 sample and load it into a capillary tube, controlling the filling height to approximately 3 mm and compacting it. Then, set the heating rate of the melting point apparatus. The rate is 5.0℃ / min, which is typically five times the rate of conventional standard methods. After heating is started, a photoelectric sensor is used to sample the data at a certain frequency. That is, the sampling time interval Simultaneously record furnace temperature and transmitted light intensity.

[0041] Because the acquired photoelectric signals are easily affected by the movement of tiny particles inside the sample, producing spike noise, direct use will affect the stability of subsequent calculations. Therefore, it is necessary to perform moving average filtering on the transmitted light intensity, including: setting the filtering window to 5 sampling times, for... Time, from Time's up The average value calculated from all transmitted light intensities collected at each time point is used as... The intensity of transmitted light at any given moment.

[0042] After preprocessing the furnace temperature and transmitted light intensity at all times during the heating process, furnace temperature sequence and transmitted light intensity sequence are constructed respectively. In this way, by filtering and smoothing the dataset, a more accurate dataset can be obtained, effectively eliminating the interference of instantaneous noise and providing a stable signal source for subsequent calculations based on the rate of change of light intensity.

[0043] S2: Determine the all-solid reference light intensity and the all-liquid reference light intensity based on the transmitted light intensity sequence, and calculate the instantaneous phase transition factor by combining the light intensity change rate at each moment to characterize the heat absorption degree of the anti-yellowing agent sample.

[0044] After obtaining a pure and smooth light intensity sequence, it was considered that simply knowing the magnitude of the light intensity was insufficient to determine the degree of thermal hysteresis, as thermal hysteresis is determined by the rate of heat absorption. During the rapid melting stage, the sample absorbs a large amount of heat, resulting in the largest deviation between the temperature and the sensor reading; while after slow melting or complete melting, the deviation is smaller. The magnitude of thermal hysteresis mainly depends on thermal resistance and the amount of heat absorbed. Solid powders have high thermal resistance and absorb a large amount of heat during melting, while liquids have relatively low thermal resistance. Changes in light intensity directly reflect the collapse rate of the crystal structure, i.e., the phase transition rate.

[0045] This step aims to construct an index that can assess the intensity of melting in real time. When the index increases, it indicates that the sample is undergoing a violent phase transition, with strong heat absorption and high thermal resistance. At this time, the temperature difference is the largest, and the subsequent temperature compensation model needs to increase the compensation strength. When the index decreases, it indicates that the heat absorption of the sample is weakened or stopped, and it is in a stable solid preheating stage or liquid heating stage. The subsequent temperature compensation model needs to reduce the compensation strength or not compensate at all.

[0046] First, determine the all-solid-state reference light intensity and the all-liquid-state reference light intensity:

[0047] The heating process is divided into an initial stage and a stable stage based on the transmitted light intensity sequence. Specifically, considering historical heating experience, the transmitted light intensity of the anti-yellowing agent sample usually shows a stable trend 30 seconds after the start of heating. Therefore, the first 30 seconds are considered the initial stage, and the period from 30 seconds to the end of heating is considered the stable stage.

[0048] The average transmitted light intensity at all times during the initial stage is taken as the all-solid-state reference light intensity, and the average transmitted light intensity at all times during the stable stage is taken as the all-liquid-state reference light intensity.

[0049] Then, calculate the rate of change of light intensity by subtracting the transmitted light intensity of the previous moment from the transmitted light intensity at each moment, and then dividing by the time interval between the current moment and the previous moment to obtain the rate of change of light intensity at that moment.

[0050] Next, determine the instantaneous phase transition factor:

[0051]

[0052] In the formula, for The instantaneous phase transition factor at time t is a dimensionless value; a larger value indicates stronger heat absorption. for The intensity of transmitted light at any given moment. The light intensity is a solid-state reference, reflecting the ability of the solid powder to block light (low light transmittance) in the initial stage of heating. The reference light intensity is for the entire liquid state, reflecting the light transmission capability (or high light transmittance) of the liquid sample at the end of the heating process. , and The units of measurement are all lux. This is a preset numerical stability constant, set to 1, used to prevent the denominator from being 0. This is a preset weighting coefficient, with a value of 0.8, used to amplify the influence of the rate of change of light intensity. for The rate of change of light intensity over time, measured in lux per second. It is the absolute value symbol.

[0053] In this relation, the first term The transmitted light intensity represents the normalized transmitted light intensity, reflecting the melting process of the anti-yellowing agent sample. As the anti-yellowing agent transitions from a solid to a liquid state, the transmittance gradually increases from low to high, indicating the progress of melting. from Towards As the value approaches 1, it not only represents the current light transmittance but also essentially characterizes the melting process (percentage of phase transition). The second term... It is a dynamic enhancement term that reflects how fast the sample melts. The larger the value, the more abrupt the change in transmittance, indicating that the crystal is collapsing.

[0054] The melting process and melting speed are combined by multiplication, taking into account the physical facts: as melting progresses, the faster the melting speed, the larger the instantaneous phase change factor, which means that the anti-yellowing agent sample absorbs more heat and has a greater thermal hysteresis. When the sample has not yet started to melt or has already completely melted, the instantaneous phase change factor is smaller, which means that the anti-yellowing agent sample absorbs less heat and has a smaller thermal hysteresis. When the anti-yellowing agent sample is in the middle of the melting process and the crystal collapses rapidly, both factors increase simultaneously, causing the instantaneous phase change factor to surge. Through this nonlinear weighting, the heat absorption intensity is accurately quantified, and the high thermal hysteresis range is accurately identified.

[0055] It should be noted that all formulas in this invention are empirical formulas, and the physical parameters involved in the formulas are all calculated using their values ​​in the International System of Units (SI) in a dimensionless manner.

[0056] In one example, suppose in time:

[0057] Known , , , Sampling interval Then the rate of change of light intensity is: Calculate the instantaneous phase transition factor .

[0058] Thus, by constructing a transient phase change factor, the invisible endothermic phase change process inside the anti-yellowing agent sample can be transformed into a visible numerical index, when the sample is in the intense melting stage. This will increase significantly, indicating that subsequent steps require greater temperature compensation.

[0059] S3: Based on the instantaneous phase change factor, a dynamic thermal hysteresis compensation model is constructed. The furnace temperature at that moment is nonlinearly corrected using the dynamic thermal hysteresis compensation model to invert and restore the true sample temperature of the anti-yellowing agent sample at each moment, so as to obtain the true sample temperature sequence.

[0060] After quantifying the instantaneous heat absorption of the anti-yellowing agent sample, it was considered that existing correction methods typically only subtract a fixed temperature value for linear correction, assuming that the thermal hysteresis is constant. However, according to thermodynamic laws, the true temperature difference consists of two parts: the basic heat transfer temperature difference and the phase change endothermic temperature difference. During melting, the sample absorbs latent heat, and the temperature rise stops, while the sensor temperature continues to rise. At this time, the temperature difference between the temperature collected by the furnace sensor and the true temperature of the sample will dynamically widen. A fixed correction value cannot simulate this dynamic process, resulting in a corrected temperature that is not only numerically higher but also distorted in form.

[0061] Therefore, this step introduces a nonlinear compensation term that is positively correlated with the instantaneous phase change factor to construct a dynamic thermal hysteresis compensation model. The dynamic thermal hysteresis compensation model is then used to nonlinearly correct the furnace temperature at that moment, with the aim of retrieving and restoring the true sample temperature of the anti-yellowing agent sample.

[0062] Specifically, it is based on the following relation:

[0063]

[0064] In the formula, For the anti-yellowing agent sample in The actual sample temperature at any given time. for Furnace temperature at all times and The unit of measurement is Celsius. The heating rate for rapidly heating the anti-yellowing agent sample is 5. The unit of measurement is degrees Celsius per second. This is the inherent basic hysteresis time constant of the melting point apparatus, with a typical value of 0.8 min. The preset basic thermal resistance constant is set to 1. The preset phase change endothermic gain coefficient is set to 2.5. for The instantaneous phase transition factor at time t is used as a square root function to smooth the compensation curve.

[0065] In this relation, This represents the total temperature difference caused by thermal hysteresis, which is the total amount of temperature compensation that needs to be made up. This represents the fundamental linear thermal hysteresis caused by heating rate and instrument thermal resistance when no phase transition occurs. The effect of phase transition is introduced, when The large size indicates that the anti-yellowing agent sample melted violently. Significantly increased, leading to Increase. The furnace temperature collected by the sensor is corrected through subtraction.

[0066] When the anti-yellowing agent sample is in the solid heating period The amount is very small, and the total compensation is basically constant. Follow A linear increase, once it enters the melting period, The surge led to a rapid increase in total compensation. The rate of increase is forcibly reduced, and even a temporary horizontal plateau or depression is formed on the curve. This is the true physical manifestation of a substance absorbing latent heat. By introducing the nonlinear adjustment of the phase change factor, adaptive compensation for dynamic thermal hysteresis is achieved, and the effect of restoring the true temperature curve of slow heating is achieved at high heating rates.

[0067] In one example, the sample data from step S2 is as follows:

[0068] Assuming furnace temperature ℃, ;

[0069] but Total compensation: ;

[0070] Actual temperature: ℃, if no drastic phase transition occurs at this point, If it is very small, the compensation amount is approximately ℃, at this time As can be seen from the temperature, when the phase transition is intense, the compensation amount increases significantly, from 4.0 to 28.942, thus forming a plateau or depression on the curve, which accurately reproduces the physical endothermic phenomenon during melting.

[0071] Thus, by using a dynamic thermal hysteresis compensation model, the real temperature curve under slow heating can be reproduced during rapid heating without the need for expensive hardware (such as infrared thermal imagers), effectively eliminating dynamic thermal hysteresis.

[0072] After obtaining the actual sample temperature of the anti-yellowing agent sample at each moment, the actual sample temperatures at all moments are combined into an actual sample temperature sequence.

[0073] S4: The initial melting point and total melting point of the anti-yellowing agent sample are determined by the temperature sequence and transmitted light intensity sequence of the real sample. Based on the initial melting point, total melting point and theoretical melting point, the product purity score is calculated, thereby realizing rapid detection of the quality of the anti-yellowing agent product.

[0074] Therefore, this step aims to establish a comprehensive scoring mechanism that analyzes the full melting point and initial melting point of the anti-yellowing agent sample based on the actual sample temperature sequence and transmitted light intensity sequence, generating an intuitive product purity score and enabling rapid detection of product quality.

[0075] First, determine the initial melting point and total melting point of the anti-yellowing agent sample: in the transmitted light intensity sequence, the transmitted light intensity reaches... At this point, the actual sample temperature corresponding to the first characteristic moment is recorded as the initial melting point, and the transmitted light intensity reaches [value missing]. At this point, the actual sample temperature corresponding to the second characteristic moment is recorded as the total melting point, where... As the all-solid-state reference light intensity, The reference light intensity is set for the entire liquid state. This setting can eliminate the interference of signal noise on feature point recognition and conforms to the general statistical standard used in industry for defining the initial melting and full melting of materials with a wide melting range, that is, eliminating the first and last 10% of the nonlinear tail region and locking in the core temperature range of the phase transition.

[0076] Then, calculate the product purity score:

[0077] ；

[0078] In the formula, The purity score for a product is a dimensionless numerical value ranging from 0 to 100. The preset penalty coefficient is 500. This refers to the temperature value of the full melting point. This is the temperature value of the initial melting point. and The units of measurement are all in degrees Celsius. The temperature values ​​represent the theoretical standard melting point of the anti-yellowing agent sample. The theoretical standard melting point of anti-yellowing agent HN-150 is 152 degrees Celsius. It is a logarithmic function used to evaluate the widening of the melting range at high temperatures.

[0079] In this relation, This indicates the relative melting range width, reflecting the amount of impurities. The more impurities, the wider the melting range; a higher value for this item results in a greater deduction of points. (The last item...) It is a high-temperature penalty term, utilizing the monotonically increasing property of the logarithmic function.

[0080] The melting range width and high temperature level are combined using a multiplicative method for scoring. When the sample purity is very high, the melting range is extremely short, the molecular weight is close to zero, the deduction is minimal, and the score is close to 100. When the sample contains impurities, the melting range widens, especially if the impurities cause the full melting point to be affected. Abnormally high (common in the deterioration of anti-yellowing agents). This will further amplify the deductions, meaning that for the same melting range, if it occurs in a higher temperature range, more points will be deducted. Through this weighted design, a dual assessment of product purity and thermal stability is achieved, resulting in an objective and cautionary quality score.

[0081] In one example, assume that it is known ℃, ℃, ℃; Calculate the melting range difference: Melting range ratio: Logarithmic terms: Deductions: Product purity rating: .

[0082] Thus, this scoring mechanism not only considers the melting range width but also introduces a logarithmic penalty for absolute temperature, enabling the scoring results to more comprehensively reflect the impurity content and thermal stability of the product, providing an objective quality basis for product delivery.

[0083] Finally, after calculating the product purity score, the process also includes: obtaining a preset quality grading threshold table, comparing the product purity score with the thresholds in the quality grading threshold table, determining the quality grade of the anti-yellowing agent sample, and outputting the result. For example, 80 to 100 points is excellent, with a quality grade of Level 1; 60 to 80 points is average, with a quality grade of Level 2; and below 60 points is unqualified, with a quality grade of Level 3.

[0084] To visually demonstrate the effectiveness of the technical solution of this invention, combined with Figure 2 and Figure 3 The figure illustrates the dynamic characteristics of the transmitted light intensity sequence over time during rapid heating. Initially, the curve is low and stable, corresponding to the dominant region of the all-solid-state reference light intensity in the technical solution. This indicates the anti-yellowing agent sample is in the solid powder region, with a complete crystal structure and blocked light. As heating progresses, the curve shows an S-shaped rise, corresponding to the melting phase transition region in the technical solution. Within this region, the transmitted light intensity increases rapidly, and the rate of change of light intensity increases significantly, indicating that the sample is undergoing a violent endothermic phase transition. Later in the curve, the value reaches a high level and remains stable, corresponding to the dominant region of the all-liquid reference light intensity, meaning the sample is in a liquid state and has completely melted. The moment corresponding to the initial melting point marks the effective start of the phase transition, and the moment corresponding to the full melting point marks the end of the main phase transition. Figure 3The paper intuitively demonstrates the effectiveness of the dynamic thermal hysteresis compensation model proposed in this invention in eliminating errors caused by rapid heating. Existing technologies, with fixed corrections, only linearly shift the sensor temperature, reducing the numerical value but completely losing the concave characteristics during melting and failing to reflect the nonlinear temperature difference caused by phase change endothermic heating. The curve corresponding to the dynamically corrected temperature in this invention closely coincides with the true reference value for slow heating. This curve is obtained by nonlinearly correcting the furnace temperature using the dynamic thermal hysteresis compensation model. In the phase change region, it exhibits a clear concave characteristic, proving that when a drastic change in light intensity is detected, this invention automatically increases the temperature compensation by increasing the instantaneous phase change factor, thereby accurately reconstructing the true physical melting process from the artificially inflated furnace temperature and effectively solving the dynamic thermal hysteresis problem.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rapid testing method for the quality of anti-yellowing agents based on a melting point apparatus, characterized in that, include: The anti-yellowing agent sample was rapidly heated using a melting point apparatus. The furnace temperature and transmitted light intensity were collected at each moment during the heating process to obtain the furnace temperature sequence and transmitted light intensity sequence. Based on the transmitted light intensity sequence, the all-solid reference light intensity and the all-liquid reference light intensity were determined, and the rate of change of light intensity at each moment was calculated. The instantaneous phase transition factor was calculated based on the light intensity change rate, the all-solid-state reference light intensity, and the all-liquid-state reference light intensity to characterize the endothermic degree of the anti-yellowing agent sample. A dynamic thermal hysteresis compensation model is constructed based on the instantaneous phase change factor. The furnace temperature at that moment is nonlinearly corrected using the dynamic thermal hysteresis compensation model to invert and restore the true sample temperature of the anti-yellowing agent sample at each moment, so as to obtain the true sample temperature sequence. The initial melting point and total melting point of the anti-yellowing agent sample were determined by identifying feature points in the temperature sequence and transmitted light intensity sequence of the real sample. The theoretical melting point of the anti-yellowing agent sample is obtained, and the product purity score is calculated based on the initial melting point, the total melting point, and the theoretical melting point, thereby enabling rapid detection of the quality of the anti-yellowing agent product. The method for determining the all-solid-state reference light intensity and the all-liquid-state reference light intensity based on the transmitted light intensity sequence is as follows: The heating process is divided into an initial stage and a steady stage based on the transmitted light intensity sequence. The average transmitted light intensity at all times in the initial stage is taken as the all-solid reference light intensity, and the average transmitted light intensity at all times in the steady stage is taken as the all-liquid reference light intensity. The instantaneous phase transition factor is based on the following relationship: In the formula, for The instantaneous phase transition factor at time t, for The intensity of transmitted light at any given moment. As the all-solid-state reference light intensity, As a reference light intensity in a fully liquid state, This is a preset numerical stability constant used to prevent the denominator from being zero. These are preset weighting coefficients used to amplify the influence of the rate of change of light intensity. for Rate of change of light intensity over time It is the absolute value symbol; The actual sample temperature of the anti-yellowing agent sample at each moment is based on the following relationship: In the formula, For the anti-yellowing agent sample in The actual sample temperature at any given time. for Furnace temperature at all times The heating rate for rapidly heating the anti-yellowing agent sample, This is the inherent fundamental lag time constant of the melting point apparatus. The preset basic thermal resistance constant, This is the preset phase change endothermic gain coefficient. for The instantaneous phase transition factor at a given moment.

2. The rapid testing method for anti-yellowing agent product quality according to claim 1, characterized in that, After collecting the furnace temperature and transmitted light intensity at each moment during the heating process, the following preprocessing operations are performed: A preset filtering window is used. At each time point, a moving average filtering process is performed on the furnace temperature and transmitted light intensity at that time according to the filtering window to achieve smooth preprocessing of the furnace temperature and transmitted light intensity at that time.

3. The rapid testing method for the quality of anti-yellowing agents according to claim 1, characterized in that, The rate of change of light intensity is determined based on the following method: The rate of change of light intensity at each moment is obtained by subtracting the transmitted light intensity of the previous moment from the transmitted light intensity at each moment and then dividing by the time interval between the current moment and the previous moment.

4. The rapid testing method for the quality of anti-yellowing agents according to claim 1, characterized in that, By identifying feature points in the temperature and transmitted light intensity sequences of real samples, the initial melting point and total melting point of the anti-yellowing agent sample were determined, including: In the transmitted light intensity sequence, the transmitted light intensity reaches At this point, the actual sample temperature corresponding to the first characteristic moment is recorded as the initial melting point, and the transmitted light intensity reaches [value missing]. At this point, the actual sample temperature corresponding to the second characteristic moment is recorded as the total melting point, where... As the all-solid-state reference light intensity, The reference light intensity is for the entire liquid state.

5. The rapid testing method for the quality of anti-yellowing agents according to claim 1, characterized in that, The product purity score is calculated based on the initial melting point, total melting point, and theoretical melting point, using the following relationship: ； In the formula, Rate the product purity. The preset penalty coefficient, This refers to the temperature value of the full melting point. This is the temperature value of the initial melting point. The temperature value representing the theoretical standard melting point of the anti-yellowing agent sample. It is a logarithmic function.

6. The rapid testing method for the quality of anti-yellowing agents according to claim 5, characterized in that, After calculating the product purity score, the following is also included: Obtain the preset quality grading threshold table, compare the product purity score with the threshold in the quality grading threshold table, determine the quality grade of the anti-yellowing agent sample, and output it.

7. The rapid testing method for the quality of anti-yellowing agents according to claim 1, characterized in that, The anti-yellowing agent sample was rapidly heated using a melting point apparatus, and the furnace temperature and transmitted light intensity were collected at each moment during the heating process. This included grinding the anti-yellowing agent sample, loading it into a capillary tube and compacting it, setting the heating rate of the melting point apparatus to 5.0℃ / min, and then using a photoelectric sensor to synchronously collect the furnace temperature and transmitted light intensity at each moment after starting the heating.

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