A method for constructing a component analysis model of a spandex and glue polyester blended fabric

Abstract

The application provides a component analysis model construction method for a spandex and polyester blended fabric, and relates to the textile detection technical field.In view of the problem of large deviation of the test result in the prior art, the spandex fiber sample is dissolved and treated by using an ethanol / sodium hydroxide mixed solvent, and a spandex mass change correction coefficient is obtained by testing; the same blended fabric sample is tested in parallel by using the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method, the measured spandex mass fraction is obtained by using the ethanol / sodium hydroxide test method, and the measured polyester fiber mass fraction is obtained by using the 75% sulfuric acid test method; the measured spandex mass fraction is corrected according to the spandex mass change correction coefficient; the real spandex mass fraction and the gum content are obtained based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction; and the component analysis model is constructed by linearly fitting the corrected measured spandex mass fraction and the real spandex mass fraction.The application has high test result accuracy.

Description

Technical Field

[0001] This invention relates to the field of textile testing technology, and in particular to a method for constructing a composition analysis model for a blend of PVC-coated polyester and spandex fabrics. Background Technology

[0002] Blended polyester and spandex fabrics combine the crispness, abrasion resistance, and wrinkle resistance of polyester fibers with the high elasticity of spandex, making them widely used in sportswear, functional clothing, and other fields. They are currently the mainstream elastic fabric with the largest usage and widest applicability in the textile industry. To ensure product quality and accurate fiber content labeling, standardized and high-precision quantitative analysis of the composition of these fabrics is a crucial technical support for production quality control and product testing.

[0003] Currently, the traditional 75% sulfuric acid method is commonly used for quantitative analysis of the composition of polyester and spandex blended fabrics. This method calculates the content by selectively dissolving one component and is a standard testing method in the industry. However, in actual testing of sizing polyester and spandex blended fabrics, the sizing components on the fabric surface or inside the fabric dissolve along with the fibers and participate in the calculation of mass change, leading to significant deviations in the spandex content test results.

[0004] Therefore, developing a method for constructing a composition analysis model for blended polyester and spandex fabrics is of great significance for improving the accuracy of test results. Summary of the Invention

[0005] To address the problem of significant deviations in test results in existing technologies, this invention proposes a method for constructing a composition analysis model for blended polyester and spandex fabrics, specifically including the following steps: S1. The spandex fiber sample was dissolved using a mixed solvent of ethanol / sodium hydroxide, and the correction coefficient for the mass change of spandex was calculated. S2. The composition of the blended polyester and spandex fabric is divided into three parts: polyester fiber, spandex and rubber. The same blended fabric samples are tested in parallel using the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method. The measured mass fraction of spandex is obtained by the ethanol / sodium hydroxide test method, and the measured mass fraction of polyester fiber is obtained by the 75% sulfuric acid test method. S3. Correct the measured spandex mass fraction according to the spandex mass change correction coefficient; S4. Based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubber content are calculated. S5. Linearly fit the corrected measured spandex mass fraction with the true spandex mass fraction to construct a composition analysis model for blended polyester and spandex fabrics.

[0006] Furthermore, in step S1, the spandex fiber sample is dissolved using a mixed solvent of ethanol / sodium hydroxide, and the correction coefficient for the mass change of spandex is calculated. This includes: drying the spandex fiber sample to constant weight and cooling it, and weighing the dry weight before dissolution; dissolving the spandex fiber sample by shaking using a mixed solvent of ethanol / sodium hydroxide, washing, drying, cooling, and weighing the remaining fiber after dissolution; and calculating the correction coefficient for the mass change of spandex based on the dry weight of the spandex fiber before and after dissolution.

[0007] Furthermore, the formula for calculating the correction factor for spandex mass change is as follows: ; Where d represents the correction coefficient for the change in spandex mass, m0 represents the dry weight of spandex fiber before dissolution, and m1 represents the dry weight of spandex fiber after dissolution.

[0008] Furthermore, in step S2, the same blended fabric sample is tested in parallel using the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method, respectively. This includes: dividing the PVC-coated polyester and spandex blended fabric sample into two equal parts; dissolving, washing, drying and weighing one part of the sample using the ethanol / sodium hydroxide test method; and dissolving, washing, drying and weighing the other part of the sample using the 75% sulfuric acid test method.

[0009] Furthermore, in step S3, the measured spandex mass fraction is corrected according to the spandex mass change correction coefficient, which includes multiplying the measured spandex mass fraction by the spandex mass change correction coefficient to obtain the corrected measured spandex mass fraction.

[0010] Furthermore, in step S4, the actual mass fraction of spandex and the glue content are calculated based on the measured mass fraction of polyester fiber and the corrected measured mass fraction of spandex, including: calculating the actual mass fraction of spandex by normalizing the component proportion based on the measured mass fraction of polyester fiber and the corrected measured mass fraction of spandex, and calculating the glue content by subtracting the total content.

[0011] Furthermore, the formula for calculating the true mass fraction of spandex is as follows: ; in, This indicates the actual mass fraction of spandex. This indicates the corrected measured spandex mass fraction. This indicates the measured mass fraction of polyester fiber.

[0012] Furthermore, the formula for calculating the rubber content is: ; in, This indicates the rubber content.

[0013] Furthermore, in step S5, the corrected measured spandex mass fraction and the true spandex mass fraction are linearly fitted to construct a composition analysis model for blended polyester and spandex fabrics. This includes: collecting multiple sets of blended fabric samples with different glue contents, obtaining the corrected measured spandex mass fraction and the true spandex mass fraction for each set according to steps S1-S4; and using the least squares method to perform univariate linear regression fitting on the two sets of data to obtain the composition analysis model for blended polyester and spandex fabrics.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses an ethanol / sodium hydroxide mixed solvent to dissolve spandex fiber samples and calculates the spandex mass change correction coefficient. The composition of the rubbery-impregnated polyester / spandex blended fabric is divided into three parts: polyester fiber, spandex, and rubbery. Parallel tests are performed on the same blended fabric samples using both the ethanol / sodium hydroxide method and the 75% sulfuric acid method. The measured spandex mass fraction is obtained using the ethanol / sodium hydroxide method, and the measured polyester fiber mass fraction is obtained using the 75% sulfuric acid method. The measured spandex mass fraction is corrected according to the spandex mass change correction coefficient. Based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubbery content are calculated. A linear fit is performed between the corrected measured spandex mass fraction and the true spandex mass fraction to construct a compositional analysis model for the rubbery-impregnated polyester / spandex blended fabric. By determining the spandex mass change correction coefficient and correcting the test values, the accuracy of the basic data is improved. By constructing a three-component system and calculating the true spandex mass fraction and rubbery content, quantitative characterization and error tracing of rubbery interference are achieved. A dedicated calibration model for spandex mass fraction was established by fitting the least squares method, which reduced the detection deviation caused by glue interference, making the spandex content detection results closer to the true value and improving the accuracy of the test results. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart of a method for constructing a composition analysis model for a polyester and spandex blended fabric provided in an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0018] The specific embodiments of the present invention will be described below.

[0019] To address the issue of significant deviations in test results in existing technologies, this invention employs an ethanol / sodium hydroxide mixed solvent to dissolve spandex fiber samples, obtaining a correction coefficient for spandex mass variation. Parallel tests are then conducted on the same blended fabric samples using both the ethanol / sodium hydroxide method and the 75% sulfuric acid method. The ethanol / sodium hydroxide method yields the measured spandex mass fraction, while the 75% sulfuric acid method yields the measured polyester fiber mass fraction. The measured spandex mass fraction is corrected using the correction coefficient. Based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubber content are obtained. A linear fit is then performed between the corrected measured spandex mass fraction and the true spandex mass fraction to construct a component analysis model. This invention provides highly accurate test results.

[0020] This invention provides a method for constructing a composition analysis model for blended polyester and spandex fabrics. Figure 1 This is a flowchart of a method for constructing a composition analysis model for a polyester / spandex blended fabric provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the specific steps include the following: S1. The spandex fiber sample was dissolved using a mixed solvent of ethanol and sodium hydroxide, and the correction coefficient for the mass change of spandex was calculated.

[0021] The ethanol / sodium hydroxide mixed solvent is prepared by mixing anhydrous ethanol and sodium hydroxide in a fixed ratio. It is a mixed reagent used for the selective dissolution of spandex fibers. For example, the ratio of anhydrous ethanol to sodium hydroxide is 200 mL / 16 g. The spandex fiber sample is a pure spandex standard sample with a specification of 77.8 dtex, used to determine the mass correction factor. The spandex mass change correction factor is a correction factor that reflects the degree of mass change of spandex fibers after dissolution, washing, and drying in the ethanol / sodium hydroxide solvent. It is used to compensate for the trace mass loss of spandex during the test, making the test results closer to the true value.

[0022] Specifically, the spandex fiber sample was dissolved using a mixed solvent of ethanol / sodium hydroxide, and the correction coefficient for the mass change of spandex was calculated. This included: drying the spandex fiber sample to constant weight and cooling it, and weighing the dry weight before dissolution; dissolving the spandex fiber sample by shaking with the mixed solvent of ethanol / sodium hydroxide, washing, drying, cooling and weighing the remaining fiber after dissolution; and calculating the correction coefficient for the mass change of spandex based on the dry weight of the spandex fiber before and after dissolution.

[0023] The spandex fiber sample was dried to constant weight in a rapid eight-basket oven at (105±3)℃. After being removed and cooled to room temperature in a desiccator, the initial dry weight (i.e., dry weight before dissolution) was measured using an AL204 electronic balance with an accuracy of 0.001g. The sample was then transferred to a stoppered Erlenmeyer flask, and 100mL of a 200mL / 16g ethanol / sodium hydroxide mixed solvent was added to immerse the sample. The flask was sealed and placed in a 70℃ constant temperature water bath shaker for 15 minutes. After the reaction, the mixture was filtered into a pre-weighed glass frit crucible. After draining the liquid by gravity, a vacuum pump was started to remove the residual solvent. The remaining spandex fiber in the crucible was repeatedly washed with distilled water, and the liquid was drained after each wash. The crucible and the remaining fiber were dried, cooled, and weighed again to obtain the dry weight after dissolution.

[0024] The formula for calculating the correction factor for spandex mass change is: ; Where d represents the correction coefficient for the change in spandex mass, m0 represents the dry weight of spandex fiber before dissolution, and m1 represents the dry weight of spandex fiber after dissolution.

[0025] Based on the above-mentioned test and calculation method for the spandex mass change correction coefficient, the spandex mass change correction coefficient obtained by dissolving spandex fiber with a specification of 77.8 dtex is shown in Table 1.

[0026] Table 1 Correction coefficients for spandex mass variation By standardizing and unifying the drying, dissolving, washing, weighing, and coefficient calculation steps, the mass change pattern of spandex fiber during the testing process is accurately determined, and a stable and reliable correction coefficient for spandex mass change is obtained. This coefficient is used to correct subsequent test data, eliminate systematic errors caused by experimental operations and solvents, and improve the accuracy and consistency of spandex content detection.

[0027] S2. The composition of the blended polyester and spandex fabric is divided into three parts: polyester fiber, spandex and rubber. Parallel tests are performed on the same blended fabric samples using the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method. The measured mass fraction of spandex is obtained by the ethanol / sodium hydroxide test method, and the measured mass fraction of polyester fiber is obtained by the 75% sulfuric acid test method.

[0028] Glue-coated polyester and spandex blended fabrics refer to textiles with a coating or adhesive layer, composed of polyester fibers, spandex, and adhesive. Parallel testing refers to simultaneously testing the same sample under identical conditions using two different methods to ensure complete consistency of the sample baseline in the two sets of data, eliminating interference from sampling differences.

[0029] Specifically, parallel tests were conducted on the same blended fabric samples using the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method, including: dividing the sizing polyester and spandex blended fabric samples into two equal parts; dissolving, washing, drying and weighing one part of the sample using the ethanol / sodium hydroxide test method; and dissolving, washing, drying and weighing the other part of the sample using the 75% sulfuric acid test method.

[0030] The sample of the polyester-spandex blended fabric with uniform composition was divided into two parallel samples. One sample was subjected to dissolution, washing, drying and weighing in sequence using the ethanol / sodium hydroxide test method. The other sample was subjected to dissolution, washing, drying and weighing in the same procedure using the 75% sulfuric acid test method to obtain two sets of comparable test data.

[0031] By dividing the same sample into two equal parts and testing them separately using two different methods, it is possible to ensure that the test samples are from the same source and that the test conditions are comparable, thus avoiding systematic errors caused by sample differences.

[0032] S3. Correct the measured spandex mass fraction according to the spandex mass change correction coefficient.

[0033] Specifically, this involves multiplying the measured spandex mass fraction by the spandex mass change correction factor to obtain the corrected measured spandex mass fraction.

[0034] The measured spandex mass fraction refers to the uncorrected spandex mass fraction obtained directly using the ethanol / sodium hydroxide test method. The corrected measured spandex mass fraction refers to the spandex mass fraction that is corrected for the spandex mass change by the spandex mass change correction factor, resulting in a spandex mass fraction that is closer to the true state.

[0035] The measured spandex mass fraction obtained by the ethanol / sodium hydroxide test method is multiplied by a pre-determined correction factor for spandex mass change. This correction factor compensates for the mass loss of spandex during the dissolution process, yielding the corrected measured spandex mass fraction. Correcting the measured value using the spandex mass change correction factor effectively eliminates systematic errors caused by trace mass losses during the dissolution, washing, and drying processes of spandex fibers, thus improving the accuracy of spandex mass fraction testing.

[0036] For example, 28 groups of rubbery blended fabric samples were divided into two parts according to the above equal division rules. Both parts were dried to constant weight in an oven at (105±3)℃, cooled to room temperature, and weighed using an electronic balance with an accuracy of 0.001g. The first part of the sample was operated according to the ethanol / sodium hydroxide method: 100mL of a mixed solvent of ethanol / sodium hydroxide with a ratio of 200mL / 16g was added, and the mixture was shaken in a constant temperature water bath at 70℃ for 15min. The mixture was then filtered into a glass frit crucible with a known dry weight. After gravity drainage and vacuum suction, the residual fibers were repeatedly washed with distilled water. After each washing, the residual liquid was suctioned out. Finally, the sample was dried, cooled, and weighed. The corrected measured spandex mass fraction was calculated using the spandex mass change correction coefficient. The second sample was prepared according to the 75% sulfuric acid method: 100 mL of 75% sulfuric acid solution was added, and the sample was shaken in a constant temperature water bath at 50±5℃ for 60 min. After filtration with a known filter, the remaining fibers were washed once with sulfuric acid of the same temperature and concentration, and then thoroughly washed with distilled water. After drying and cooling, the sample was weighed, and the measured polyester fiber mass fraction was calculated.

[0037] Parallel testing eliminates the baseline deviation caused by uneven glue content and fiber distribution in different samples, making the two sets of data directly comparable. At the same time, there is no need to add an extra step of separate glue testing. The measured value can be obtained through just one parallel test, avoiding the loss of fiber through repeated fiber processing in traditional step-by-step testing and reducing the introduction of errors in the operation process.

[0038] S4. Based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubber content are calculated.

[0039] The true mass fraction of spandex refers to the actual mass fraction of spandex in the fabric after removing the interference of sizing agents. Sizing refers to the mass fraction of sizing agents in a blend of sizing polyester and spandex, used to quantitatively characterize the degree of sizing interference.

[0040] Specifically, based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubber content are calculated, including: based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction is calculated by normalizing the component proportions, and the rubber content is calculated by subtracting the total content.

[0041] Component proportion normalization refers to the calculation method that uses the corrected ratio of the measured spandex mass fraction to the measured polyester fiber mass fraction to obtain the true mass fraction of spandex. Total content deduction method. The total content deduction method uses 100% as a baseline and deducts the corrected measured spandex mass fraction and the measured polyester fiber mass fraction to obtain the proportion of rubber.

[0042] The formula for calculating the true mass fraction of spandex is: ; in, This indicates the actual mass fraction of spandex. This indicates the corrected measured spandex mass fraction. This indicates the measured mass fraction of polyester fiber.

[0043] The formula for calculating the rubber content is: ; in, This indicates the rubber content.

[0044] The above calculation rules do not require separate separation and weighing of the adhesive beforehand. They can output two core parameters simultaneously based solely on existing test data, simplifying the detection process for adhesive-containing fabrics. The detection time for a single sample is reduced by more than 40%. At the same time, the normalization process avoids the inclusion of adhesive in fiber loss, accurately obtaining the true mass fraction of spandex and quantitatively characterizing the degree of adhesive interference.

[0045] S5. Linearly fit the corrected measured spandex mass fraction with the true spandex mass fraction to construct a composition analysis model for blended polyester and spandex fabrics.

[0046] Specifically, this includes: collecting multiple sets of blended fabric samples with different sizing rates, obtaining the corrected measured spandex mass fraction and the true spandex mass fraction for each set according to steps S1-S4; and using the least squares method to perform univariate linear regression fitting on the two sets of data to obtain the composition analysis model of sizing polyester and spandex blended fabrics.

[0047] Univariate linear regression fitting refers to the process of finding the optimal linear equation y=ax+b using the corrected measured spandex mass fraction as the independent variable x and the actual spandex mass fraction as the dependent variable y. The core is to determine the coefficients a and b that best fit the data trend by minimizing the sum of squared residuals between the predicted and actual values ​​of all data points. a is the slope and b is the intercept.

[0048] For example, 28 groups of polyester and spandex blended fabric samples with different sizing rates were collected. Each group was tested separately: each sample was divided into two equal parts, and parallel tests were performed using the ethanol / sodium hydroxide method and the 75% sulfuric acid method, respectively. The measured spandex value using the ethanol / sodium hydroxide method was corrected using a spandex mass change correction coefficient to obtain the corrected measured spandex mass fraction. The true spandex mass fraction of each group was calculated using the component proportion normalization formula, and the paired data of the corrected measured spandex mass fraction and the true spandex mass fraction of all groups were summarized. A univariate linear regression was performed on these paired data using the least squares method to obtain the fitted equation y = 0.04 + 1.05x, the coefficient of determination R of this model. 2The correlation coefficient reached 0.99, and the Pearson correlation coefficient was 0.99, indicating a highly significant linear positive correlation between the corrected measured spandex mass fraction and the true spandex mass fraction.

[0049] By establishing a highly correlated linear correction model, the corrected measured spandex mass fraction can be directly converted into the true spandex mass fraction, effectively offsetting the detection deviation caused by the rubber, improving the accuracy and stability of the detection results, and enabling rapid output of accurate results in a single test, simplifying the operation process and improving detection efficiency.

[0050] In this embodiment, spandex fiber samples were dissolved using an ethanol / sodium hydroxide mixed solvent, and the spandex mass change correction coefficient was calculated. The composition of the rubbery-impregnated polyester and spandex blended fabric was divided into three parts: polyester fiber, spandex, and rubbery. Parallel tests were performed on the same blended fabric samples using both the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method. The measured spandex mass fraction was obtained using the ethanol / sodium hydroxide test method, and the measured polyester fiber mass fraction was obtained using the 75% sulfuric acid test method. The measured spandex mass fraction was corrected according to the spandex mass change correction coefficient. Based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubbery content were calculated. The corrected measured spandex mass fraction and the true spandex mass fraction were linearly fitted to construct a composition analysis model for the rubbery-impregnated polyester and spandex blended fabric. By determining the spandex mass change correction coefficient and correcting the test values, the accuracy of the basic data was improved. By constructing a three-component system and calculating the true spandex mass fraction and rubbery content, quantitative characterization and error tracing of rubbery interference were achieved. A dedicated calibration model for spandex mass fraction was established by fitting the least squares method, which reduced the detection deviation caused by glue interference, making the spandex content detection results closer to the true value and improving the accuracy of the test results.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a compositional analysis model for PVC-coated polyester and spandex blended fabrics, characterized in that, include: S1. The spandex fiber sample was dissolved using a mixed solvent of ethanol / sodium hydroxide, and the correction coefficient for the mass change of spandex was calculated. S2. The composition of the blended polyester and spandex fabric is divided into three parts: polyester fiber, spandex and rubber. The same blended fabric samples are tested in parallel using the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method. The measured mass fraction of spandex is obtained by the ethanol / sodium hydroxide test method, and the measured mass fraction of polyester fiber is obtained by the 75% sulfuric acid test method. S3. Correct the measured spandex mass fraction according to the spandex mass change correction coefficient; S4. Based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubber content are calculated. S5. Linearly fit the corrected measured spandex mass fraction with the true spandex mass fraction to construct a composition analysis model for blended polyester and spandex fabrics.

2. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 1, characterized in that, In step S1, the spandex fiber sample is dissolved using a mixed solvent of ethanol and sodium hydroxide, and the correction coefficient for the mass change of the spandex is calculated, including: The spandex fiber sample was dried to constant weight and cooled, and its dry weight before dissolution was measured. The spandex fiber sample was dissolved by shaking using a mixed solvent of ethanol / sodium hydroxide. The remaining fibers after dissolution were washed, dried, cooled, and weighed. The correction factor for the change in spandex mass is calculated based on the dry weight of spandex fiber before and after dissolution.

3. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 2, characterized in that, The formula for calculating the correction factor for spandex mass change is: ； Where d represents the correction coefficient for the change in spandex mass, m0 represents the dry weight of spandex fiber before dissolution, and m1 represents the dry weight of spandex fiber after dissolution.

4. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 1, characterized in that, In step S2, parallel tests are performed on the same blended fabric samples using the ethanol / sodium hydroxide test method and the 75% sulfuric acid test method, respectively, including: The sample of the blended polyester and spandex fabric was divided into two equal parts. One sample was dissolved, washed, dried, and weighed using the ethanol / sodium hydroxide test method. Another sample was dissolved, washed, dried, and weighed using the 75% sulfuric acid test method.

5. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 1, characterized in that, In step S3, the measured spandex mass fraction is corrected according to the spandex mass change correction coefficient, including: Multiply the measured spandex mass fraction by the spandex mass change correction factor to obtain the corrected measured spandex mass fraction.

6. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 1, characterized in that, In step S4, based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction and rubber content are calculated, including: Based on the measured polyester fiber mass fraction and the corrected measured spandex mass fraction, the true spandex mass fraction was calculated by normalizing the component proportions, and the rubber content was calculated by subtracting the total content.

7. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 6, characterized in that, The formula for calculating the true mass fraction of spandex is: ； in, This indicates the actual mass fraction of spandex. This indicates the corrected measured spandex mass fraction. This indicates the measured mass fraction of polyester fiber.

8. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 6, characterized in that, The formula for calculating the rubber content is: ； in, This indicates the rubber content.

9. The method for constructing a composition analysis model for PVC-coated polyester and spandex blended fabrics according to claim 1, characterized in that, In step S5, the corrected measured spandex mass fraction is linearly fitted to the true spandex mass fraction to construct a composition analysis model for blended polyester and spandex fabrics, including: Multiple sets of blended fabric samples with different rubber contents were collected, and the corrected measured spandex mass fraction and the true spandex mass fraction for each set were obtained according to steps S1-S4. The least squares method was used to perform univariate linear regression fitting on the two sets of data to obtain the composition analysis model of the polyester-spandex blended fabric.

Images