A method for achieving a skin feel uv coating on a cosmetic package

Abstract

This invention relates to the field of cosmetic packaging technology, specifically disclosing a method for achieving a skin-feel UV coating on cosmetic packaging. The method includes: acquiring historical processing test data and conducting migration tests; using two-dimensional skin-feel oil separation comparison analysis to determine the curing mismatch of the current skin-feel UV coating; if curing mismatch exists, extracting the effective thickness-energy set, constructing a thickness-energy regression mapping model to determine the thickness curing energy set; then, based on curing reaction kinetics, calculating the temperature effect coefficient of curing temperature on curing energy; combining this with the theoretical curing temperature range to obtain the temperature curing energy set; finally, through thickness-temperature cross-validation, obtaining the final curing energy set; and after effect verification analysis, determining the final curing energy. This achieves optimal matching of different coating thicknesses, curing temperatures, and curing parameters, effectively avoiding problems such as excessive migration of substances and abnormal color, and improving the coating performance compliance rate and production stability.

Description

Technical Field

[0001] This invention relates to the field of cosmetic packaging technology, and more specifically to a method for achieving a skin-feeling UV coating on cosmetic packaging. Background Technology

[0002] As the cosmetics industry develops towards high-end and refined products, the appearance, texture, and safety performance of cosmetic packaging are receiving increasing attention. Skin-feel UV coatings, with their advantages such as solvent-free production, fast curing speed, delicate and skin-friendly surface, scratch resistance, and prominent matte texture, have been widely used in the field of high-end cosmetic packaging and have broad market application prospects.

[0003] However, in the actual production and application of skin-feel UV coatings for cosmetic packaging, existing methods have significant technical shortcomings, failing to effectively solve the coating curing mismatch problem, resulting in low coating performance compliance rates and poor production stability. Firstly, the compatibility between curing parameters and coating thickness is insufficient. Existing methods lack a correlation mapping model between coating thickness and curing energy, using fixed curing energy parameters, which may lead to both excessive migration of substances and abnormal color. Secondly, there is a lack of a quantitative correlation mechanism between curing temperature and curing energy. Existing skin-feel UV coating methods do not study the intrinsic relationship between curing temperature and curing energy based on curing reaction kinetics, nor do they calculate the temperature efficiency coefficient to clarify the compensation or reduction of curing energy per unit temperature change. Relying solely on operator experience to adjust curing temperature and energy parameters may lead to unstable curing effects at different curing temperatures and coating thicknesses, resulting in low coating performance compliance rates and requiring repeated testing and adjustments, severely restricting the high-quality, large-scale application of skin-feel UV coatings in the cosmetic packaging field.

[0004] Therefore, the present invention provides a method for achieving a skin-feeling UV coating on cosmetic packaging. Summary of the Invention

[0005] The purpose of this invention is to provide a method for achieving a skin-feeling UV coating on cosmetic packaging, in order to solve the problems mentioned above.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for achieving a skin-feel UV coating on cosmetic packaging includes: Migration tests were conducted using processing test data to determine the total migration amount of the skin-feel UV coating. Two-dimensional skin-feel oil separation comparison analysis was used to determine whether there was a curing mismatch in the skin-feel UV coating. If curing mismatch exists, extract the effective thickness-energy set contained in the processing test data, and construct a thickness-energy regression mapping model through the correlation mapping analysis between coating thickness and curing energy to determine the thickness curing energy set; By correlating and analyzing the curing temperature and curing energy contained in the processing test data, the temperature effect coefficient of curing temperature on curing energy is obtained, and the set of curing energy at different temperatures is calculated and determined. By cross-validation analysis of the thickness curing energy set and the temperature curing energy set, the final curing energy set of the skin-feel UV coating is determined, and the effect verification analysis of the curing energy is carried out to determine the final curing energy of the skin-feel UV coating.

[0007] Furthermore, the process for determining the total migration amount of the skin-feel UV coating is as follows: The processing test data includes: the coating thickness, curing temperature, curing energy, and coating color difference value of the skin-feel UV coating; Based on the migration test of skin-feel UV coating, the total mass of migratable substances is extracted, the surface area of ​​the sample is measured, and the ratio of the total mass of migratable substances to the surface area of ​​the sample is calculated to obtain the total migration amount of skin-feel UV coating.

[0008] Furthermore, the process of determining whether there is a curing mismatch in the skin-feel UV coating through two-dimensional skin-feel oil separation comparison analysis is as follows: The two-dimensional skin-feel oil separation comparison analysis includes: migration dimension comparison and color difference dimension comparison; The migration dimension comparison process is as follows: if the total migration amount is not within the preset standard range, the migration dimension comparison is deemed to have failed. The process of color difference dimension comparison is as follows: if the coating color difference value is not within the preset standard range, the color difference dimension comparison is deemed to have failed. If both the migration dimension comparison and the color difference dimension comparison fail, it is determined that there is a curing mismatch in the skin-feel UV coating.

[0009] Furthermore, the process of extracting the effective thickness-energy set contained in the processing test data is as follows: Based on the processing test data, the coating thickness and curing energy of each batch were extracted. The coating thickness and curing energy of the same batch are combined to obtain the original thickness-energy group, and each original thickness-energy group is effectively tested: If both the migration dimension comparison and the color difference dimension comparison of the original thickness-energy group pass, then the original thickness-energy group is marked as the effective thickness-energy group, and all effective thickness-energy groups are integrated to obtain the effective thickness-energy group set.

[0010] Furthermore, through the correlation mapping analysis between coating thickness and curing energy, the process of constructing a thickness-energy regression mapping model is as follows: Based on the effective thickness-energy set, the coating thickness and curing energy are extracted separately and then time-series integrated to obtain the thickness time series and energy time series. The absolute value of the Pearson correlation coefficient between the thickness time series and the energy time series is calculated to obtain the correlation coefficient. If the correlation coefficient is greater than or equal to the linear correlation coefficient, a univariate polynomial regression model is constructed, the thickness time series and the energy time series are substituted into it, and the least squares method is used to fit the model to obtain the thickness-energy regression mapping model. If the correlation coefficient is less than the linear correlation coefficient, construct nonlinear models of bivariate linear, higher-order polynomial, exponential, power function and trigonometric function respectively, use the least squares method for fitting, and calculate the determination coefficient of each nonlinear model. Take the nonlinear model with the largest determination coefficient as the thickness-energy regression mapping model.

[0011] Furthermore, the process of determining the thickness-curing energy set is as follows: A standard range for coating thickness is defined, and each coating thickness in the standard range is substituted into the thickness-energy regression mapping model to obtain the curing energy of the corresponding skin-feel UV coating. The results are then integrated to obtain the set of thickness curing energies.

[0012] Furthermore, the process of obtaining the temperature efficiency coefficient of curing temperature on curing energy through correlation calculation and analysis is as follows: The gas constant, activation energy and pre-exponential factor of the crosslinking and curing reaction of the skin-feeling UV coating resin were obtained, and the rate constant benchmark and the rate constant corresponding to each curing temperature were calculated respectively. Based on the effective thickness-energy set, the curing temperature of the same batch as the curing energy and coating thickness is extracted and integrated to obtain the curing temperature sequence; Calculate the ratio of each rate constant to the rate constant reference, and use it as the curing efficiency influence coefficient; The mean of the energy time series is calculated to obtain the solidification energy baseline; Based on any curing efficiency influence coefficient, the ratio of the curing energy benchmark to the curing efficiency influence coefficient is calculated to obtain the theoretical curing energy at the corresponding curing temperature. All theoretical curing energies are then integrated to obtain the theoretical curing energy sequence. The ratio of the difference between adjacent theoretical curing energies in the theoretical curing energy sequence to the difference between adjacent curing temperatures in the corresponding curing temperature sequence is calculated to obtain the undetermined temperature efficiency coefficient. Calculate the mean of all undetermined temperature efficiency coefficients to obtain the temperature efficiency coefficient of curing temperature on curing energy.

[0013] Furthermore, the process of calculating the rate constant baseline and the rate constant corresponding to each curing temperature is as follows: The arithmetic mean of the curing temperature series is calculated as the curing temperature reference. The curing temperature reference and each curing temperature in the curing temperature sequence are converted into thermodynamic temperatures. Then, the gas constant, the activation energy of the crosslinking curing reaction of the skin-feel UV coating resin, and the pre-exponential factor are respectively combined and substituted into the Arrhenius equation to obtain the rate constant reference and the rate constant corresponding to each curing temperature.

[0014] Furthermore, the calculation determined the temperature-curing energy collection process as follows: Based on any theoretical curing temperature within the theoretical curing temperature range of the skin-feeling UV coating, the product of the theoretical curing temperature and the temperature efficiency coefficient is processed to obtain the curing energy corresponding to the theoretical curing temperature. By integrating the curing energies corresponding to all theoretical curing temperatures, a set of temperature-curing energies is obtained.

[0015] Furthermore, the final curing energy set of the skin-feel UV coating is determined, and the effect verification analysis of the curing energy value is performed. The process of determining the final curing energy of the skin-feel UV coating is as follows: The thickness curing energy set and the temperature curing energy set are processed according to the principle of merging similar values ​​by data reduction to obtain the final curing energy set of the skin-feel UV coating; For any curing energy in the final curing energy set, the migration amount of the skin-feel UV coating is tested, and the total migration amount and coating color difference value are extracted. The ratio of the difference between the total migration amount corresponding to the curing energy and the lower limit of the standard range of total migration amount to the lower limit is calculated to obtain the migration optimization rate. The color difference optimization rate is obtained by calculating the ratio of the difference between the coating color difference value corresponding to the curing energy and the mean value of the coating color difference standard range to the mean value. The sum of migration optimization rate and color difference optimization rate is used as the selection evaluation value, and the curing energy corresponding to the maximum selection evaluation value is used as the final curing energy of the skin-feel UV coating.

[0016] The beneficial effects of this invention are: Benefit 1: It solves the problem of insufficient compatibility between coating thickness and curing energy, and avoids the dual hidden dangers of excessive migration of substances and abnormal color. By determining the set of curing energy that is compatible with the standard range of coating thickness, skin-feel UV coatings of different thicknesses can obtain the appropriate curing energy, avoiding the problems of excessive total migration and oil seepage caused by insufficient curing.

[0017] Benefit 2: Establishing a correlation mechanism between curing temperature and curing energy to improve the stability of curing effect; by calculating the temperature effect coefficient of curing temperature on curing energy, the set of curing energy that matches the theoretical curing temperature range is determined, and then the final set of curing energy is obtained through cross-verification of thickness and temperature. This ensures that the curing energy matches the coating thickness and the curing temperature, thereby improving the coating performance compliance rate. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a flowchart illustrating the steps involved in achieving a skin-feeling UV coating on cosmetic packaging. Figure 2 This is a logic diagram illustrating a method for achieving a skin-feeling UV coating on cosmetic packaging. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0021] Please see Figures 1-2 As shown, this invention is a method for achieving a skin-feel UV coating on cosmetic packaging. This invention primarily addresses the problem of unstable curing effects caused by thickness fluctuations leading to excessive migration of substances and abnormal color during the large-scale production of skin-feel UV coatings for cosmetic packaging. By detecting and judging curing mismatches, a thickness-energy regression mapping model is constructed, and the temperature efficiency coefficient is calculated. Through cross-validation and effect verification, the final curing energy is determined, ultimately avoiding related hidden dangers and improving the coating performance compliance rate and production stability. The method includes the following steps: Step 1: Obtain historical processing test data of skin-feel UV coating on cosmetic packaging, and conduct migration test on the skin-feel UV coating on cosmetic packaging to determine the total migration amount of the skin-feel UV coating. Through two-dimensional skin-feel oil separation comparison analysis, determine whether there is curing mismatch of the skin-feel UV coating. In step one, the historical processing and testing data of the skin-feel UV coating for cosmetic packaging refers to the processing and testing data of the skin-feel UV coating for cosmetic packaging within the historical statistical period, including but not limited to: the coating thickness, curing temperature, curing energy and coating color difference value of the skin-feel UV coating. The historical statistical duration refers to the time period from the start of production of the current skin-feel UV coating for cosmetic packaging to the present moment. The processing test data can be obtained by: measuring the coating thickness of the skin-feel UV coating using an eddy current thickness gauge; measuring the instantaneous surface temperature of the coating inside the curing machine, i.e., the curing temperature, using an infrared thermometer; and measuring the energy value during the UV curing process using a handheld UV energy meter, with the unit being mJ / cm². 2 The color difference value of the coating is measured by a spectrophotometer; In step one, the migration amount of the skin-feel UV coating on the cosmetic packaging is tested to determine the total migration amount of the skin-feel UV coating. Cut the skin-feel UV coating area of ​​the cosmetic packaging to be tested into a standard-sized sample, clean the surface and dry to constant weight; Select a food simulation solution (water) suitable for cosmetic packaging, and set the soaking temperature (50℃) and time (24h). The soaking solution was evaporated, dried, and weighed to constant weight. The total mass of migratable substances was determined by gravimetric method. Measure the sample surface area and calculate the ratio of the total mass of migratable substances to the sample surface area to obtain the total migration amount of the skin-feel UV coating (total migration per unit area of ​​the sample surface area corresponding to the skin-feel UV coating, in μg / cm²). 2 ); In step one, the two-dimensional skin-feel oil separation comparison analysis refers to comparing the measured values ​​of the two indicators with the corresponding preset standard ranges using the total migration amount and coating color difference value of the skin-feel UV coating as two judgment dimensions, thereby judging the degree of coating curing crosslinking, the risk of oil separation and seepage, and the process compatibility. In step one, the process of two-dimensional skin-feel oil separation comparison analysis is as follows: Migration dimension comparison: The total migration amount of the skin-feel UV coating is compared with the preset total migration amount standard range: If the total migration of the skin-feeling UV coating is within the preset total migration standard range, it indicates that the content of migratable substances in the coating is compliant, the curing and cross-linking are sufficient, there is no obvious risk of oil separation or exudation, and the migration dimension comparison is passed. If the total migration amount of the skin-feel UV coating is not within the preset total migration amount standard range, it indicates that the coating is not cured enough, the crosslinking density is too low, and there are curing mismatch problems such as small molecule migration and oil seepage. The migration dimension comparison fails. Color difference comparison: Compare the coating color difference value with the preset coating color difference standard range. If the coating color difference value is within the preset coating color difference standard range, it indicates that the coating is cured evenly, the process matching is good, the color and curing state meet the requirements, and the color difference dimension comparison is passed. If the coating color difference value is not within the preset coating color difference standard range, it indicates that the coating curing is uneven, the degree of cross-linking is abnormal, the curing state is mismatched with the process requirements, and the color difference dimension comparison fails. The preset total migration standard range and the preset coating color difference standard range are set according to the color difference control requirements for the total migration limit of migratable substances in HG / T 5778-2020 "Ultraviolet (UV) Curable Coatings for Cosmetic Packaging Materials".

[0022] In step one, the process of determining whether there is a curing mismatch in the skin-feel UV coating is as follows: If both the migration dimension comparison and the color difference dimension comparison fail, it indicates that the coating has problems with small molecule migration and oil seepage, as well as uneven curing, abnormal color, and severe insufficient curing crosslinking. It is determined that there is a curing mismatch in the skin-feel UV coating. If both the migration dimension comparison and the color difference dimension comparison pass, it means that the content of the migratable substances in the coating is compliant, the curing is uniform and sufficient, there is no oil seepage or abnormal color, the curing crosslinking state and process matching meet the requirements, and it is determined that there is no curing mismatch of the skin-feel UV coating. It should be noted that if the migration dimension comparison and the color difference dimension comparison pass, but the other fails, it means that the coating only has a single dimension of performance deviation and does not have serious migration oil separation and uneven curing problems at the same time. The processing parameters of the skin-feel UV coating should be adjusted accordingly and the test should be re-tested and verified. Then, the two-dimensional skin-feel oil separation comparison analysis should be carried out again to determine whether there is a curing mismatch of the skin-feel UV coating.

[0023] Step 2: If a curing mismatch is determined to exist in the skin-feel UV coating, extract the effective thickness-energy set, and construct a thickness-energy regression mapping model through the correlation mapping analysis between coating thickness and curing energy to determine the thickness curing energy set; In step two, the effective thickness-energy set refers to the set of all qualified thickness-curing energy data sets obtained by combining the coating thickness and curing energy of each batch of coatings one by one based on the processing test data of the skin-feel UV coating of historical cosmetic packaging. After effectively inspecting and eliminating any invalid groups that fail the migration dimension comparison or color difference dimension comparison, the set of all qualified thickness-curing energy data sets is obtained. In step two, the process of extracting the effective thickness-energy set is as follows: Based on historical processing test data of UV coatings for skin feel on cosmetic packaging: The coating thickness and curing energy of each batch were extracted separately; The coating thickness and curing energy of the same batch are combined to form the original thickness-energy group; Effective verification was performed on each original thickness-energy group: If either the migration dimension comparison or the color difference dimension comparison of the original thickness-energy group fails, the original thickness-energy group will be discarded. If both the migration dimension comparison and the color difference dimension comparison of the original thickness-energy group pass, then the original thickness-energy group is marked as the effective thickness-energy group, and all effective thickness-energy groups are integrated to obtain the effective thickness-energy group set. In step two, the correlation mapping analysis between coating thickness and curing energy refers to: extracting the thickness time series and energy time series based on the effective thickness-energy set, determining whether there is a linear correlation between the two by calculating the Pearson correlation coefficient, and fitting the coating thickness and curing energy with univariate polynomial regression if there is a linear correlation, and fitting multiple nonlinear models and selecting the optimal model if there is no linear correlation, thereby analyzing the correlation between coating thickness and curing energy and constructing the corresponding mapping relationship between the two. In step two, the process of constructing the thickness-energy regression mapping model is as follows: Based on effective thickness-energy settling: The coating thickness and curing energy were extracted separately and then integrated to obtain the thickness time series and the energy time series. Calculate the Pearson correlation coefficient between the thickness time series and the energy time series, and take the absolute value to obtain the correlation coefficient; If the correlation coefficient is greater than or equal to the linear correlation coefficient (preferably 0.7, a commonly used industry standard for determining linear correlation), it indicates that there is a linear correlation between the coating thickness and curing energy of the skin-feel UV coating. A univariate polynomial regression model was constructed by substituting the thickness time series and the energy time series according to the correspondence of the same batch, and fitting them by the least squares method to obtain the thickness-energy regression mapping model. If the correlation coefficient is less than the linear correlation coefficient, it indicates that there is no linear relationship between the coating thickness of the skin-feel UV coating and the curing energy. Nonlinear models were constructed respectively: bivariate linear model, higher-order polynomial model, exponential model, power function model and trigonometric function model; The least squares method was used for fitting, the determination coefficient of the nonlinear model was calculated, and the nonlinear model corresponding to the maximum value of the determination coefficient was taken as the thickness-energy regression mapping model. In step two, the process of determining the thickness curing energy set is as follows: The standard range for coating thickness is set based on the requirement in HG / T 5778-2020 that "the surface temperature of the substrate is controlled at 20-30℃ to avoid deformation of plastics such as PET / PMMA, and the temperature fluctuation during the curing process is ≤±2℃ to ensure uniform coating thickness (deviation ≤±1μm)". Based on any coating thickness within the standard range of coating thickness, substitute it into the thickness-energy regression mapping model to obtain the curing energy of the corresponding skin-feel UV coating; By integrating the curing energies corresponding to the standard range of coating thickness, a set of thickness curing energies is obtained; It should be noted that the physical significance of the thickness curing energy set is that this set is a set of compliant curing energies that are compatible with the standard thickness range of skin-feel UV coatings for cosmetic packaging. Its physical essence is that within this energy set, skin-feel UV coatings of different thicknesses can achieve full and uniform cross-linking curing. This ensures that the coating meets the core performance requirements of the standard, such as skin feel, adhesion, and scratch resistance. It also ensures that the total migration and color difference of the coating meet the preset standards from the energy dimension, avoiding curing mismatch problems.

[0024] Step 3: Based on the curing reaction kinetics, the temperature effect coefficient of curing temperature on curing energy is obtained through correlation calculation and analysis of curing temperature and curing energy. Combined with the theoretical curing temperature range of skin-feel UV coating, the temperature curing energy set is calculated. In step three, the curing reaction kinetics refers to: based on the Arrhenius equation as the core theoretical foundation, studying the quantitative regulation law of the curing temperature on the reaction rate constant in the crosslinking curing reaction of skin-feel UV coating resin, as well as the influence mechanism of the rate constant change on the coating curing efficiency, revealing the quantitative correlation between curing temperature and curing energy for compensation or reduction, and a kinetic theory system that can calculate the required curing energy compensation value by using known curing temperature and resin activation energy theory. In step three, the correlation calculation and analysis between curing temperature and curing energy refers to the following process: based on the Arrhenius equation, combined with the curing temperature sequence and energy time sequence extracted from the effective thickness-energy set, the curing efficiency influence coefficient is derived by calculating the curing temperature benchmark, rate constant benchmark, and curing energy benchmark, and then the undetermined temperature efficiency coefficient is calculated and the average value is taken to obtain the final temperature efficiency coefficient. This process determines the compensation or reduction correlation between curing temperature and curing energy and establishes a quantitative correspondence between the two. In step three, the calculation process for the temperature efficiency coefficient of curing temperature on curing energy is as follows: The indefinite integral expression of the Arrhenius equation is: ; Where k refers to the rate constant of the crosslinking and curing reaction of the skin-feel UV coating resin (unit: s). -1 The larger the k value, the faster the curing reaction rate and the higher the cross-linking and curing efficiency of the coating. A refers to the pre-exponential factor (unit: s) -1 ), which are the inherent physical property parameters of the skin-feel UV coating resin, which can be obtained by retrieving them from the physical property manual of the supplier of the skin-feel UV coating resin; This refers to the activation energy (unit: kJ / mol) of the cross-linking and curing reaction of the skin-feel UV coating resin. It is the minimum energy required for the resin to undergo cross-linking and curing. It is an inherent physical property parameter and can be obtained from the physical property manual of the supplier of the skin-feel UV coating resin. R refers to the gas constant, which is a fixed value of 8.314 J / (mol·K). T: Curing temperature (unit: K, thermodynamic temperature, conversion formula is T=273.15+t, t is the temperature in Celsius); Based on the effective thickness-energy set, the curing energy and the curing temperature of the corresponding batch of coating thickness are extracted; The extracted curing temperatures are integrated to obtain a curing temperature sequence, and the arithmetic mean of the curing temperature sequence is calculated as the curing temperature reference. The curing temperature reference is converted into a thermodynamic temperature, and combined with the gas constant, the activation energy of the crosslinking and curing reaction of the skin-feel UV coating resin, and the pre-exponential factor are substituted into the Arrhenius equation to obtain the rate constant reference. Based on any curing temperature in the curing temperature sequence, the curing temperature is converted into a thermodynamic temperature, and combined with the gas constant, the activation energy of the crosslinking curing reaction of the skin-feel UV coating resin, and the pre-exponential factor, it is substituted into the Arrhenius equation to obtain the rate constant at that curing temperature. Calculate the ratio of the rate constant at each curing temperature to the rate constant baseline to obtain the curing efficiency influence coefficient; Based on energy time series: The mean of the energy time series is calculated to obtain the solidification energy baseline; Based on any curing efficiency influence coefficient, calculate the ratio of the curing energy benchmark to the curing efficiency influence coefficient to obtain the theoretical curing energy at the corresponding curing temperature; By integrating the theoretical solidification energies, a theoretical solidification energy sequence is obtained; The difference between adjacent theoretical curing energies in the theoretical curing energy sequence is calculated and compared with the difference between adjacent curing temperatures in the corresponding curing temperature sequence to obtain the undetermined temperature efficiency coefficient. Calculate the mean of all undetermined temperature efficiency coefficients to obtain the temperature efficiency coefficient of curing temperature on curing energy; It should be noted that the physical meaning of the curing efficiency influence coefficient is: the ratio of the resin crosslinking curing reaction rate constant at the test curing temperature to the rate constant at the reference temperature, which represents the extent to which the curing efficiency of the coating is improved or reduced by the temperature compared to the reference temperature; the physical meaning of the temperature efficiency coefficient of curing temperature to curing energy is: the average change in theoretical curing energy corresponding to a unit change in curing temperature, which reflects the extent to which the curing energy required for the coating to meet the standard is compensated or reduced for every 1°C change in curing temperature.

[0025] The calculation logic of the temperature efficiency coefficient of curing temperature on curing energy is as follows: extract the original data set of actual production temperature and curing energy, calculate the curing reaction baseline rate at the average temperature of the production line, obtain the curing efficiency improvement or attenuation ratio of each temperature relative to the baseline temperature, derive the theoretical energy value required for the coating to achieve standard curing at different temperatures, obtain the energy adjustment range corresponding to a single set of temperature changes, and finally take the average value to obtain the average amount of curing energy that needs to be compensated or reduced for every 1°C change in temperature (i.e., the temperature efficiency coefficient).

[0026] In step three, the process of obtaining the theoretical curing temperature range of the skin-feel UV coating is as follows: The theoretical curing temperature range for the skin-feel UV coating is set according to the curing performance requirements in Clause 4.4.6 of HG / T 5778-2020. In step three, the process of calculating the temperature curing energy set is as follows: Based on any theoretical curing temperature within the theoretical curing temperature range of the skin-feel UV coating: The curing energy corresponding to the theoretical curing temperature is obtained by multiplying the theoretical curing temperature by the temperature efficiency coefficient of the curing energy. By integrating all curing energies, a set of temperature curing energies is obtained; It should be noted that the physical meaning of the temperature curing energy set is that this set is a collection of compliant curing energies that correspond one-to-one with each temperature in the theoretical curing temperature range of the skin-feel UV coating. Each curing energy in the set corresponds to a temperature value within the theoretical curing temperature range, and this curing energy can ensure that the skin-feel UV coating achieves full cross-linking curing at the corresponding temperature, meeting the performance requirements such as total migration and color difference, ensuring curing matching under different temperature conditions, and avoiding curing mismatch problems.

[0027] Step 4: Based on the thickness curing energy set and the temperature curing energy set, the final curing energy set of the skin-feel UV coating is obtained through thickness-temperature cross-validation analysis. The effect verification analysis of the curing energy value is then performed to determine the final curing energy of the skin-feel UV coating. In step four, the final curing energy set of the skin-feel UV coating is obtained through thickness-temperature cross-validation analysis as follows: Based on the set of thickness curing energy and the set of temperature curing energy, the two sets are processed by the principle of merging similar values ​​to reduce the data, so as to obtain the final set of curing energy for the skin-feel UV coating. The principle of merging similar values ​​in data reduction refers to setting a standard for the numerical difference (preferably 0.1 mJ / cm²) for discrete energy values ​​in two sets. 2 When the difference between any two curing energies in the thickness curing energy set and the temperature curing energy set does not exceed this standard (for example, 3.50 mJ / cm), 2 With 3.58mJ / cm 2 4.22 mJ / cm 2 With 4.29 mJ / cm 2 The solidification energies that are similarly discrete are grouped into the same effective range and regarded as the similar intersection of the two sets. For solidification energies that are discrete with completely identical values, they are directly included in the intersection. It should be noted that if the intersection of the thickness curing energy set and the temperature curing energy set is empty, it indicates that there is a parameter mismatch problem in the currently set coating thickness standard range, theoretical curing temperature range, or temperature efficiency coefficient calculation. This results in no overlap between the thickness-adapted curing energy and the temperature-adapted curing energy. In this case, it is necessary to readjust the coating thickness standard range and the theoretical curing temperature range, or recalculate the temperature efficiency coefficient, optimize the thickness-energy regression mapping model, recalculate the two energy sets, and find the intersection again until a valid intersection is obtained. This ensures that the final curing energy range can meet the dual adaptation requirements of coating thickness and curing temperature, and guarantees that the skin-feel UV coating cures to the standard.

[0028] In step four, the process of verifying and analyzing the effect of curing energy value and determining the final curing energy of the skin-feel UV coating is as follows: Based on any curing energy from the final curing energy set of the skin-feel UV coating: The migration amount of the skin-feel UV coating was tested (the test environment was the same as that for the migration amount test of the skin-feel UV coating on cosmetic packaging, only the curing energy was different), and the total migration amount and coating color difference value of the skin-feel UV coating after the test were extracted. The color difference values ​​of each coating and the total migration amount are integrated separately to obtain the color difference sequence and the total migration sequence for effect verification. Any total migration amount in the total migration sequence based on effect verification: Calculate the difference between the total migration amount and the lower limit of the standard range of the total migration amount, and then perform a ratio operation between the difference and the lower limit of the standard range of the total migration amount to obtain the migration optimization rate; The reason for selecting the lower limit of the total migration standard range is that the lower the total migration, the less migratable substances there are, and the lower the risk of oil precipitation and seepage. Therefore, the closer it is to the lower limit of the standard, the higher the compliance and safety.

[0029] Color difference value of any coating in the color difference sequence based on effect verification: Calculate the difference between the coating color difference value and the mean of the coating color difference standard range, and then perform a ratio calculation between the difference and the mean of the coating color difference standard range to obtain the color difference optimization rate; The reason for selecting the average value of the standard range of coating color difference is that the core requirement of coating color difference is uniform color. The preset standard range is the qualified range, and the median value is the most ideal color state within the range. If it deviates from the median value, whether it is too high or too low, there will be problems of uneven color and uneven curing. Therefore, the closer it is to the median value, the better the appearance and curing uniformity.

[0030] Based on any curing energy from the final curing energy set of the skin-feel UV coating: The sum of the migration optimization rate and the color difference optimization rate is calculated to obtain the evaluation value for the optimal curing energy. The curing energy corresponding to the maximum selected evaluation value is taken as the final curing energy of the skin-feel UV coating; It should be noted that if the migration optimization rate and color difference optimization rate are negative, that is, the migration dimension comparison and color difference dimension comparison are not satisfied, they are directly eliminated and will not affect the selection of the final curing energy; if there are two corresponding curing energies for the maximum selection evaluation value, the smaller one is selected as the final curing energy, considering energy consumption performance.

[0031] The working principle of this invention is as follows: First, by combining historical processing test data and migration amount tests with two-dimensional skin-feel oil separation comparison analysis, it is determined whether there is a curing mismatch. If so, effective data is extracted to construct a thickness-energy regression mapping model, and the temperature effect coefficient is calculated based on curing reaction kinetics to obtain the curing energy set for suitable thickness and temperature. Then, through cross-validation and effect verification, the optimal final curing energy is determined, ultimately achieving precise matching of curing parameters under different working conditions, avoiding problems such as excessive migration of substances and abnormal color, and improving the coating performance compliance rate and production stability.

[0032] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for achieving a skin-feel UV coating on cosmetic packaging, characterized in that: include: Migration tests were conducted using processing test data to determine the total migration amount of the skin-feel UV coating. Two-dimensional skin-feel oil separation comparison analysis was used to determine whether there was a curing mismatch in the skin-feel UV coating. If curing mismatch exists, extract the effective thickness-energy set contained in the processing test data, and construct a thickness-energy regression mapping model through the correlation mapping analysis between coating thickness and curing energy to determine the thickness curing energy set; By correlating and analyzing the curing temperature and curing energy contained in the processing test data, the temperature effect coefficient of curing temperature on curing energy is obtained, and the set of curing energy at different temperatures is calculated and determined. By cross-validation analysis of the thickness curing energy set and the temperature curing energy set, the final curing energy set of the skin-feel UV coating is determined, and the effect verification analysis of the curing energy is carried out to determine the final curing energy of the skin-feel UV coating.

2. The method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The process for determining the total migration of the skin-feel UV coating is as follows: The processing test data includes: the coating thickness, curing temperature, curing energy, and coating color difference value of the skin-feel UV coating; Based on the migration test of skin-feel UV coating, the total mass of migratable substances is extracted, the surface area of ​​the sample is measured, and the ratio of the total mass of migratable substances to the surface area of ​​the sample is calculated to obtain the total migration amount of skin-feel UV coating.

3. The method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The process of determining whether there is a curing mismatch in the skin-feel UV coating through two-dimensional skin-feel oil separation comparison analysis is as follows: The two-dimensional skin-feel oil separation comparison analysis includes: migration dimension comparison and color difference dimension comparison; The migration dimension comparison process is as follows: if the total migration amount is not within the preset standard range, the migration dimension comparison is deemed to have failed. The process of color difference dimension comparison is as follows: if the coating color difference value is not within the preset standard range, the color difference dimension comparison is deemed to have failed. If both the migration dimension comparison and the color difference dimension comparison fail, it is determined that there is a curing mismatch in the skin-feel UV coating.

4. The method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The process of extracting the effective thickness-energy set contained in the processing test data is as follows: Based on the processing test data, the coating thickness and curing energy of each batch were extracted. The coating thickness and curing energy of the same batch are combined to obtain the original thickness-energy group, and each original thickness-energy group is effectively tested: If both the migration dimension comparison and the color difference dimension comparison of the original thickness-energy group pass, then the original thickness-energy group is marked as the effective thickness-energy group, and all effective thickness-energy groups are integrated to obtain the effective thickness-energy group set.

5. The method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The process of constructing a thickness-energy regression mapping model through correlation mapping analysis between coating thickness and curing energy is as follows: Based on the effective thickness-energy set, the coating thickness and curing energy are extracted separately and then time-series integrated to obtain the thickness time series and energy time series. The absolute value of the Pearson correlation coefficient between the thickness time series and the energy time series is calculated to obtain the correlation coefficient. If the correlation coefficient is greater than or equal to the linear correlation coefficient, a univariate polynomial regression model is constructed, the thickness time series and the energy time series are substituted into it, and the least squares method is used to fit the model to obtain the thickness-energy regression mapping model. If the correlation coefficient is less than the linear correlation coefficient, construct nonlinear models of bivariate linear, higher-order polynomial, exponential, power function and trigonometric function respectively, use the least squares method for fitting, and calculate the determination coefficient of each nonlinear model. Take the nonlinear model with the largest determination coefficient as the thickness-energy regression mapping model.

6. The method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The process of determining the thickness curing energy set is as follows: A standard range for coating thickness is defined, and each coating thickness in the standard range is substituted into the thickness-energy regression mapping model to obtain the curing energy of the corresponding skin-feel UV coating. The results are then integrated to obtain the set of thickness curing energies.

7. The method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The process of obtaining the temperature efficiency coefficient of curing temperature on curing energy through correlation calculation and analysis is as follows: The gas constant, activation energy and pre-exponential factor of the crosslinking and curing reaction of the skin-feeling UV coating resin were obtained, and the rate constant benchmark and the rate constant corresponding to each curing temperature were calculated respectively. Based on the effective thickness-energy set, the curing temperature of the same batch as the curing energy and coating thickness is extracted and integrated to obtain the curing temperature sequence; Calculate the ratio of each rate constant to the rate constant reference, and use it as the curing efficiency influence coefficient; The mean of the energy time series is calculated to obtain the solidification energy baseline; Based on any curing efficiency influence coefficient, the ratio of the curing energy benchmark to the curing efficiency influence coefficient is calculated to obtain the theoretical curing energy at the corresponding curing temperature. All theoretical curing energies are then integrated to obtain the theoretical curing energy sequence. The ratio of the difference between adjacent theoretical curing energies in the theoretical curing energy sequence to the difference between adjacent curing temperatures in the corresponding curing temperature sequence is calculated to obtain the undetermined temperature efficiency coefficient. Calculate the mean of all undetermined temperature efficiency coefficients to obtain the temperature efficiency coefficient of curing temperature on curing energy.

8. A method for achieving a skin-feel UV coating on cosmetic packaging according to claim 7, characterized in that: The process of calculating the baseline rate constant and the rate constant corresponding to each curing temperature is as follows: The arithmetic mean of the curing temperature series is calculated as the curing temperature reference. The curing temperature reference and each curing temperature in the curing temperature sequence are converted into thermodynamic temperatures. Then, the gas constant, the activation energy of the crosslinking curing reaction of the skin-feel UV coating resin, and the pre-exponential factor are respectively combined and substituted into the Arrhenius equation to obtain the rate constant reference and the rate constant corresponding to each curing temperature.

9. A method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The calculation process for determining the temperature-curing energy set is as follows: Based on any theoretical curing temperature within the theoretical curing temperature range of the skin-feeling UV coating, the product of the theoretical curing temperature and the temperature efficiency coefficient is processed to obtain the curing energy corresponding to the theoretical curing temperature. By integrating the curing energies corresponding to all theoretical curing temperatures, a set of temperature-curing energies is obtained.

10. A method for achieving a skin-feel UV coating on cosmetic packaging according to claim 1, characterized in that: The final curing energy set of the skin-feel UV coating is determined, and the effect verification analysis of the curing energy value is performed. The process of determining the final curing energy of the skin-feel UV coating is as follows: The thickness curing energy set and the temperature curing energy set are processed according to the principle of merging similar values ​​by data reduction to obtain the final curing energy set of the skin-feel UV coating; For any curing energy in the final curing energy set, the migration amount of the skin-feel UV coating is tested, and the total migration amount and coating color difference value are extracted. The ratio of the difference between the total migration amount corresponding to the curing energy and the lower limit of the standard range of total migration amount to the lower limit is calculated to obtain the migration optimization rate. The color difference optimization rate is obtained by calculating the ratio of the difference between the coating color difference value corresponding to the curing energy and the mean value of the coating color difference standard range to the mean value. The sum of migration optimization rate and color difference optimization rate is used as the selection evaluation value, and the curing energy corresponding to the maximum selection evaluation value is used as the final curing energy of the skin-feel UV coating.

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