Quantitative analysis method of polyester composite fiber and acetate fiber mixture

Abstract

The application discloses a quantitative analysis method of a mixture of polyester composite fibers and acetate fibers, and comprises the following steps: weighing and drying a mixture of skin-core low-melting-point polyester composite fibers and acetate fibers or triacetate fibers; cooling the dried mixture; weighing the cooled mixture; dissolving the acetate fibers or triacetate fibers in the weighed mixture; separating the skin-core low-melting-point polyester composite fibers in the dissolved mixture; and calculating the mass percentage of the skin-core low-melting-point polyester composite fibers in the mixture. The analysis result is accurate and reliable, the analysis process is efficient and simple, and the quantitative analysis cost is low.

Description

Technical Field

[0001] This invention relates to the field of quantitative analysis technology of polyester composite fibers, and particularly to a quantitative analysis method for mixtures of polyester composite fibers and acetate fibers. Background Technology

[0002] Core-sheath type low-melting-point polyester composite fiber is a composite fiber consisting of a sheath layer covering a core layer. The sheath layer is made of low-melting-point polyester (LMPET) with a melting point of 80℃~180℃, while the core layer is made of ordinary polyester (HMPET) with a melting point of 255℃~260℃. It is a new type of physically modified fiber developed in recent years. Its chemical properties differ from ordinary polyester fibers. Ordinary polyester fibers are insoluble in dichloromethane, 75% sulfuric acid, and dimethylformamide, while core-sheath type low-melting-point polyester composite fibers are partially soluble in these reagents.

[0003] For mixtures of core-sheath type low-melting-point polyester composite fibers with acetate or triacetate fibers, the manual separation method according to GB / T2910.1-2009 is time-consuming, labor-intensive, and inefficient, and not all samples are suitable for this method. The hydrochloric acid method according to GB / T 37630-2019 requires 60 minutes to dissolve acetate fibers and 70 minutes to dissolve triacetate fibers, both of which are too time-consuming and inefficient. The 20% hydrochloric acid method in Part 5 of GB / T 38015-2019, with test conditions of (70±2)°C for 30 minutes, is only applicable to acetate fibers and not triacetate fibers, and also has a long dissolution time. The 75% formic acid method in Part 10 of GB / T 38015-2019 uses organic reagents that are highly toxic and corrosive, posing a risk of operational instability. GB / T The glacial acetic acid method described in 2910.14-2009 is complex and requires 60 minutes to dissolve, making it time-consuming, labor-intensive, and inefficient.

[0004] Furthermore, because core-sheath type low-melting-point polyester composite fibers are a relatively new type of physically modified fiber developed in recent years, many testing institutions lack experience in the qualitative identification of core-sheath type low-melting-point polyester composite fibers, and may incorrectly classify them as ordinary polyester fibers. For mixtures of core-sheath type low-melting-point polyester composite fibers with acetate or triacetate fibers, quantitative analysis may incorrectly rely on the sulfuric acid method of GB / T2910.11-2009 to dissolve the acetate or triacetate fibers. However, sulfuric acid will also dissolve the sheath fibers of the core-sheath type low-melting-point polyester composite fibers, leading to erroneous quantitative results. Similarly, for mixtures of core-sheath type low-melting-point polyester composite fibers with triacetate fibers, the dichloromethane method of GB / T2910.10-2009 may be incorrectly used to dissolve the triacetate fibers. Dichloromethane will also dissolve the sheath fibers of the core-sheath type low-melting-point polyester composite fibers, resulting in erroneous quantitative results. Summary of the Invention

[0005] According to embodiments of the present invention, a quantitative analysis method for a mixture of polyester composite fibers and acetate fibers is provided, for quantitatively analyzing the mass percentage of core-sheath type low-melting-point polyester composite fibers in a mixture of core-sheath type low-melting-point polyester composite fibers and acetate fibers or triacetate fibers, comprising the following steps:

[0006] Weigh out a mixture of core-sheath type low-melting-point polyester composite fiber and acetate fiber or triacetate fiber and dry it;

[0007] The mixture after cooling and drying;

[0008] Weigh the cooled mixture;

[0009] Dissolve the acetate or triacetate fibers in the weighed mixture;

[0010] Separate the core-sheath type low-melting-point polyester composite fibers from the dissolved mixture;

[0011] Calculate the mass percentage of core-sheath type low-melting-point polyester composite fibers in the mixture.

[0012] Furthermore, the mixture is dried in an oven at a temperature of 102°C to 108°C.

[0013] Furthermore, the mixture is cooled in a dryer equipped with silica gel.

[0014] Furthermore, the mixture was weighed within 2 minutes of cooling.

[0015] Furthermore, the specific method for dissolving the acetate fiber or triacetate fiber in the weighed mixture is as follows: place the weighed mixture into an Erlenmeyer flask, add 100 ml of 20% hydrochloric acid solution per gram of mixture, and then place the Erlenmeyer flask into a water bath shaker for shaking.

[0016] Furthermore, place the Erlenmeyer flask in a water bath shaker at 78℃~82℃ and shake for 20 minutes, or place the Erlenmeyer flask in a water bath shaker at 68℃~72℃ and shake for 40 minutes.

[0017] Furthermore, the specific method for separating the core-sheath type low-melting-point polyester composite fibers from the dissolved mixture is as follows: use a dry glass core crucible of known mass to pump out the liquid or filter it with a filter screen.

[0018] Furthermore, the separated core-sheath type low-melting-point polyester composite fibers need to be washed at least 3 times with a 20% hydrochloric acid solution at 78℃~82℃, then washed at least 4 times with water at 78℃~82℃, then neutralized at least 2 times with a dilute ammonia solution, and finally thoroughly washed with water.

[0019] Furthermore, when calculating the mass percentage of core-sheath type low-melting-point polyester composite fiber in the mixture, the test result is expressed as the average of two tests. If the absolute difference between the results obtained from the two tests is greater than 1%, a third test should be conducted, and the test result is expressed as the average of the three tests.

[0020] The quantitative analysis method for the mixture of polyester composite fibers and acetate fibers according to embodiments of the present invention provides accurate and reliable analytical results, efficient and simple analytical process, and low cost of quantitative analysis.

[0021] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0022] Figure 1 This is a flowchart of a quantitative analysis method for a mixture of polyester composite fibers and acetate fibers according to an embodiment of the present invention. Detailed Implementation

[0023] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, further illustrating the present invention.

[0024] First, combine Figure 1 This invention describes a quantitative analysis method for a mixture of polyester composite fibers and acetate fibers according to embodiments of the present invention. This method is used to quantitatively analyze the mass percentage of core-sheath type low-melting-point polyester composite fibers in a mixture of core-sheath type low-melting-point polyester composite fibers and acetate fibers or triacetate fibers, and has a wide range of applications.

[0025] like Figure 1 As shown, the quantitative analysis method for a mixture of polyester composite fibers and acetate fibers according to an embodiment of the present invention includes the following steps:

[0026] S1: Weigh out the mixture of core-sheath type low melting point polyester composite fiber and acetate fiber or triacetate fiber and dry it;

[0027] S2: The mixture after cooling and drying;

[0028] S3: Weigh the cooled mixture;

[0029] S4: Dissolve the acetate fiber or triacetate fiber in the weighed mixture;

[0030] S5: Core-sheath type low-melting-point polyester composite fibers separated from the dissolved mixture;

[0031] S6: Calculate the mass percentage of core-sheath type low-melting-point polyester composite fibers in the mixture.

[0032] Next, place the weighed mixture into a weighing bottle, and dry it together with the bottle cap in an oven at a temperature of 102°C to 108°C for 1 to 2 hours.

[0033] Furthermore, the dried mixture is quickly placed into a desiccator with silica gel for cooling for 20–30 minutes.

[0034] Next, the cooled mixture is removed from the dryer and weighed within 2 minutes.

[0035] Furthermore, the specific method for dissolving acetate fiber or triacetate fiber in the weighed mixture is as follows: Place the weighed mixture into an Erlenmeyer flask, add 100 ml of 20% hydrochloric acid solution per gram of mixture, stopper the flask with a glass stopper, shake the Erlenmeyer flask to wet the mixture, and then place the Erlenmeyer flask in a water bath shaker and shake at a frequency of 80 to 100 times per minute to ensure that the reagent can completely dissolve the acetate fiber or triacetate fiber, ultimately leaving only the core-sheath type low melting point polyester composite fiber.

[0036] Furthermore, the Erlenmeyer flask is placed in a water bath shaker at 78°C–82°C and shaken for 20 minutes, or in a water bath shaker at 68°C–72°C and shaken for 40 minutes. In this embodiment, placing the Erlenmeyer flask in a water bath shaker at 80°C for 20 minutes is the optimal dissolution condition.

[0037] The chemical solubility properties of core-sheath type low-melting-point polyester composite fibers are shown in Table 1, and the solubility conditions of acetate fibers and triacetate fibers are shown in Table 2 and Table 3, respectively.

[0038] Table 1 Chemical solubility properties of core-sheath type low-melting-point polyester composite fibers

[0039]

[0040]

[0041] Table 1 shows that 75% sulfuric acid, N,N-dimethylformamide, dichloromethane, and concentrated nitric acid at room temperature can partially dissolve core-sheath type low-melting-point polyester composite fibers. Microscopic observation of the residue after dissolution revealed that the dissolved portion was the sheath layer of the core-sheath type low-melting-point polyester composite fiber. Therefore, when core-sheath type low-melting-point polyester composite fibers are blended with acetate or triacetate fibers, the sulfuric acid method according to GB / T 2910.11 cannot accurately quantify the composition, and when core-sheath type low-melting-point polyester composite fibers are blended with triacetate fibers, the dichloromethane method according to GB / T 2910.10 cannot accurately quantify the composition.

[0042] Table 2. Determination of the dissolution conditions for acetate cellulose

[0043]

[0044] Table 2 shows that acetate fiber can be dissolved by 20% hydrochloric acid at 70℃ for 30 min; 80℃ for 20 min; and 90℃ for 10 min. The optimal dissolution conditions are 80℃ for 20 min.

[0045] Table 3. Determination of Triacetyl Cellulose Dissolution Conditions (Experiment)

[0046]

[0047] Table 3 shows that triacetate fiber can be dissolved by 20% hydrochloric acid at 70℃ for 40 min, 80℃ for 20 min, and 90℃ for 10 min. The optimal dissolution conditions are 80℃ for 20 min.

[0048] Therefore, the optimal dissolution conditions for using 20% ​​hydrochloric acid to dissolve acetate or triacetate fibers are 80°C for 20 minutes, with the temperature of the water bath shaker fluctuating by 2°C.

[0049] Preparation of 20% hydrochloric acid solution: Take 1000mL of concentrated hydrochloric acid (20℃, density 1.19g / mL) and slowly add it to 800mL of distilled water. After cooling to 20℃, add more distilled water to correct the density to 1.095g / mL. The concentration should be controlled between 19.5% and 20.5%.

[0050] Furthermore, the specific method for separating the core-sheath type low-melting-point polyester composite fibers from the dissolved mixture is as follows: use a dry glass sand core crucible of known mass to pump out the liquid or filter it with a filter screen. When using a filter screen, rinse it directly with clean water and rub it if necessary to separate the dissolved substances from the core-sheath type low-melting-point polyester composite fibers.

[0051] Furthermore, the separated core-sheath type low-melting-point polyester composite fibers need to be washed at least 3 times with a 20% hydrochloric acid solution at 78℃~82℃, then washed at least 4 times with water at 78℃~82℃, then neutralized at least 2 times with a dilute ammonia solution, and finally thoroughly washed with water.

[0052] Preparation of dilute ammonia solution: Take 80 mL of concentrated ammonia solution (density 0.880 g / mL) and dilute with water to 1000 mL.

[0053] Furthermore, when calculating the mass percentage of core-sheath type low-melting-point polyester composite fiber in the mixture, the test result is expressed as the average of two tests. If the absolute difference between the results obtained from the two tests is greater than 1%, a third test should be conducted. The test result is expressed as the average of the three tests. The test result is calculated to two decimal places and rounded to one decimal place. The numerical rounding is performed in accordance with GB 8170. The fiber content is then calculated (the d value of core-sheath type low-melting-point polyester composite fiber is 1.00).

[0054] When the difference between two test results exceeds 1%, the cause of the difference needs to be analyzed. This could be due to uneven distribution of sample components, errors in weighing or calculation, or incomplete dissolution of acetate or triacetate fibers. The sample component distribution can be assessed by observing the consistency of yarn and fabric structure in different parts of the original sample. If there are errors in the calculated data, recalculate and check again. To confirm whether the acetate or triacetate fibers are incompletely dissolved, visual inspection or microscopic examination can be used to check if the remaining material after dissolution is clean.

[0055] The d-values ​​of core-sheath type low-melting-point polyester composite fibers dissolved in 20% hydrochloric acid solution at (80±2)℃ for 20 minutes are shown in Table 4.

[0056] Table 4. d-values ​​of core-sheath type low-melting-point polyester composite fibers (20% hydrochloric acid method)

[0057]

[0058] As shown in Table 4, the correction factor for dissolving core-sheath type low-melting-point polyester composite fibers in 20% hydrochloric acid solution at (80±2)℃ for 20 minutes is 1.00.

[0059] Samples were prepared by manually mixing core-sheath type low-melting-point polyester composite fibers with acetate fibers and triacetate fibers. Pure core-sheath type low-melting-point polyester composite fibers, pure acetate fibers, and pure triacetate fibers were used as laboratory test samples. A certain mass of each was weighed and manually mixed to prepare mixed samples of core-sheath type low-melting-point polyester composite fibers and acetate fibers, and mixed samples of core-sheath type low-melting-point polyester composite fibers and triacetate fibers. Five samples of each type of mixed sample were prepared, and the mixing ratio was used as the design value.

[0060] Five groups of samples from each of the two mixtures were dissolved in a 20% hydrochloric acid solution at (80±2)℃ for 20 minutes using the method described in this invention. The proportions of the core-sheath type low-melting-point polyester composite fiber, acetate fiber, and triacetate fiber were tested. The test results are shown in Tables 5 and 6, respectively.

[0061] Table 5. Test results of core-sheath type low-melting-point polyester composite fibers and acetate fibers

[0062]

[0063] Table 6. Test Results of Core-Sheath Type Low Melting Point Polyester Composite Fiber and Triacetate Fiber

[0064]

[0065]

[0066] As shown in Tables 5 and 6, the absolute deviation of the ratio prepared by this method compared with that prepared by hand is less than 1%, which proves that when the core-sheath type low melting point polyester composite fiber is blended with acetate fiber or triacetate fiber, it can be dissolved in 20% hydrochloric acid solution at (80±2)℃ for 20 minutes, and accurate results can be obtained by calculation.

[0067] The following example uses a piece of black woven fabric to test its fiber content:

[0068] Example 1: A piece of black woven fabric is characterized as a blend of core-sheath type low melting point polyester composite fiber and acetate fiber. Its fiber content is determined by chemical dissolution method.

[0069] According to the test steps of the present invention, two samples with a mass of about 1g each were cut off and dried in an oven at (105±3)℃. Then they were cooled and weighed. The mass of sample 1 was 0.9016g and the mass of sample 2 was 0.9234g.

[0070] Place the two prepared samples into an Erlenmeyer flask, add 100 mL of 20% hydrochloric acid solution to each gram of sample, stopper the flask, and shake it to wet the sample. Then place the Erlenmeyer flask in a water bath shaker at (80±2)℃ and shake for 20 min at a frequency of 80 to 100 times per min.

[0071] Use a glass frit crucible of known dry weight to drain the liquid or filter it with a filter screen (when using a filter screen, rinse directly with clean water, and rub if necessary to separate the dissolved substances from the core-sheath type low melting point polyester composite fibers). Wash the remaining fibers 3 times (or more) with a small amount of 20% hydrochloric acid solution at (80±2)℃, then wash 4 to 5 times (or more) with water at (80±2)℃, neutralize with dilute ammonia solution at least 2 times, and then wash thoroughly with water.

[0072] The remaining fibers are dried, cooled, and weighed.

[0073] The mass of the residue in sample 1 was 0.6213 g, and the mass of the residue in sample 2 was 0.6324 g.

[0074] The calculation and representation of the results are in accordance with GB / T 2910.1, and the d value of core-sheath type low melting point polyester composite fiber is 1.00.

[0075] Final results: core-sheath type low melting point polyester composite fiber 67.3%; acetate fiber 32.7% (based on standard moisture regain).

[0076] Example 2: In Example 1, the same piece of black woven fabric was identified as a blend of core-sheath type low-melting-point polyester composite fiber and acetate fiber. Its fiber content was determined by manual dissection method.

[0077] According to GB / T 2910.1, two samples were taken separately, and the core-sheath type low-melting-point polyester composite fiber and acetate fiber were separated by manual separation method. The samples were then dried, cooled, and weighed. The mass of the core-sheath type low-melting-point polyester composite fiber in sample 1 was 0.6843 g, and the mass of the acetate fiber was 0.3087 g. The mass of the core-sheath type low-melting-point polyester composite fiber in sample 2 was 0.6781 g, and the mass of the acetate fiber was 0.2978 g.

[0078] The calculation and representation of the results shall be in accordance with GB / T 2910.1. The final result is as follows:

[0079] Core-sheath type low melting point polyester composite fiber 67.8%; acetate fiber 32.2% (combined with standard moisture regain).

[0080] Example 3: In Example 1, the same piece of black woven fabric was identified as a blend of core-sheath type low-melting-point polyester composite fiber and acetate fiber. Its fiber content was obtained by dissolving it using the 75% sulfuric acid method according to GB / T 2910.11-2009.

[0081] Two samples, each weighing approximately 1g, were placed in an oven at (105±3)℃ to dry. After drying, they were cooled and weighed. The mass of sample 1 was 0.8795g and the mass of sample 2 was 0.9456g.

[0082] Place the prepared sample into an Erlenmeyer flask, add 200 mL of 75% sulfuric acid solution per gram of sample, stopper the flask with a glass stopper, shake the flask to fully wet the sample, and then keep the flask at 50℃±5℃ for 1 hour, shaking it once every 10 minutes.

[0083] Filter the residue into a glass frit crucible, drain under vacuum, and then add a small amount of sulfuric acid to clean the flask. Drain under vacuum again, add fresh sulfuric acid solution to the crucible to clean the residue, drain by gravity for at least 1 minute, and then drain under vacuum again. Wash several times with cold water, neutralize twice with dilute ammonia, and then wash with cold water. Each time, drain by gravity first, then drain under vacuum.

[0084] Finally, the remaining fibers were dried, cooled, and weighed. The mass of the residue in sample 1 was 0.3922g, and the mass of the residue in sample 2 was 0.4254g.

[0085] The calculation and representation of the results are in accordance with GB / T 2910.1, and the d value of core-sheath type low melting point polyester composite fiber is 1.00.

[0086] Final results: core-sheath type low melting point polyester composite fiber 43.2%; acetate fiber 56.8% (combined with standard moisture regain).

[0087] Example 4: A piece of white woven fabric is characterized as a blend of core-sheath type low-melting-point polyester composite fiber and triacetate fiber. Its fiber content is determined by chemical dissolution method.

[0088] According to the test steps of the present invention, two samples with a mass of about 1g each were cut off and dried in an oven at (105±3)℃. Then they were cooled and weighed. The mass of sample 1 was 0.9516g and the mass of sample 2 was 0.9309g.

[0089] Place the two prepared samples into an Erlenmeyer flask, add 100 mL of 20% hydrochloric acid solution to each gram of sample, stopper the flask, and shake it to wet the sample. Then place the Erlenmeyer flask in a water bath shaker at (80±2)℃ and shake for 20 min at a frequency of 80 to 100 times per min.

[0090] Use a glass frit crucible of known dry weight to drain the liquid or filter it with a filter screen (when using a filter screen, rinse directly with clean water, and rub if necessary to separate the dissolved substances from the core-sheath type low melting point polyester composite fibers). Wash the remaining fibers 3 times (or more) with a small amount of 20% hydrochloric acid solution at (80±2)℃, then wash 4 to 5 times (or more) with water at (80±2)℃, neutralize with dilute ammonia solution at least 2 times, and then wash thoroughly with water.

[0091] The remaining fibers were dried, cooled, and weighed. The mass of the residue in sample 1 was 0.8034 g, and the mass of the residue in sample 2 was 0.7865 g.

[0092] The calculation and representation of the results are in accordance with GB / T 2910.1, and the d value of core-sheath type low melting point polyester composite fiber is 1.00.

[0093] Final results: core-sheath type low melting point polyester composite fiber 84.1%; triacetate fiber 15.9% (combined with standard moisture regain).

[0094] Example 5: In Example 4, the same piece of white woven fabric was identified as a blend of core-sheath type low-melting-point polyester composite fiber and triacetate fiber. Its fiber content was determined by manual dissection method.

[0095] According to GB / T 2910.1, two samples were taken separately, and the core-sheath type low-melting-point polyester composite fiber and triacetate fiber were separated by manual separation method. The samples were then dried, cooled, and weighed. The mass of the core-sheath type low-melting-point polyester composite fiber in sample 1 was 0.7947 g, and the mass of the triacetate fiber was 0.1480 g. The mass of the core-sheath type low-melting-point polyester composite fiber in sample 2 was 0.6276 g, and the mass of the triacetate fiber was 0.1169 g.

[0096] The calculation and representation of the results shall be in accordance with GB / T 2910.1. The final result is as follows:

[0097] Core-sheath type low melting point polyester composite fiber 83.9%; triacetate fiber 16.1% (combined with standard moisture regain).

[0098] Example 6: In Example 4, the same white woven fabric was identified as a blend of core-sheath type low-melting-point polyester composite fiber and triacetate fiber. Its fiber content was obtained by dissolving it in dichloromethane according to GB / T 2910.10-2009.

[0099] Two samples, each weighing approximately 1g, were placed in an oven at (105±3)℃ to dry. After drying, they were cooled and weighed. The mass of sample 1 was 0.8027g and the mass of sample 2 was 0.8549g.

[0100] Place the prepared sample into an Erlenmeyer flask, add 100 mL of dichloromethane (41) per gram of sample, stopper the flask, shake the flask to fully wet the sample, and let it stand for 30 minutes, shaking it once every 10 minutes.

[0101] Filter the liquid using a glass frit crucible. Add 60 mL of dichloromethane to the residue in the Erlenmeyer flask, shake by hand, and filter it into the crucible. Wash the residue into the crucible with a small amount of dichloromethane. Vacuum the liquid out, then fill the crucible with dichloromethane and drain by gravity.

[0102] Finally, vacuum suction was performed, followed by washing with hot water. The crucible and residue were then dried, cooled, and weighed. The mass of the residue in sample 1 was 0.5080 g, and the mass of the residue in sample 2 was 0.5369 g.

[0103] The calculation and representation of the results are in accordance with GB / T 2910.1, and the d value of core-sheath type low melting point polyester composite fiber is 1.01.

[0104] Final results: core-sheath type low melting point polyester composite fiber 63.0%; triacetate fiber 37.0% (combined with standard moisture regain).

[0105] Table 7 Comparison of results from various methods and manual separation methods for quantitative analysis of core-sheath type low-melting-point polyester composite fibers and acetate fibers.

[0106]

[0107] Table 8 Comparison of results from various quantitative methods and manual separation methods for core-sheath type low-melting-point polyester composite fibers and triacetate fibers.

[0108]

[0109]

[0110] Conclusion: In typical testing procedures, technicians often mistake core-sheath type low-melting-point polyester composite fibers for ordinary polyester fibers. When these fibers are blended with acetate or triacetate fibers, the preferred methods are usually the 75% sulfuric acid method and the dichloromethane method. Tables 7 and 8 show that both the 75% sulfuric acid method and the dichloromethane method yield incorrect content results. However, using this method, dissolving the fibers in a 20% hydrochloric acid solution at (80±2)℃ for 20 minutes allows for accurate quantification of the blended products of core-sheath type low-melting-point polyester composite fibers with acetate or triacetate fibers.

[0111] Above, refer to Figure 1 A quantitative analysis method for a mixture of polyester composite fibers and acetate fibers according to embodiments of the present invention is described. The analysis results are accurate and reliable, the analysis process is efficient and simple, and the quantitative analysis cost is low.

[0112] It should be noted that, in this specification, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes that element.

[0113] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A quantitative analysis method for a mixture of polyester composite fibers and acetate fibers, used for quantitatively analyzing the mass percentage of core-sheath type low-melting-point polyester composite fibers in a mixture of core-sheath type low-melting-point polyester composite fibers and acetate fibers or triacetate fibers, characterized in that... It includes the following steps: Weigh the mixture of the core-sheath type low-melting-point polyester composite fiber and the acetate fiber or the triacetate fiber and dry it; The mixture after cooling and drying; Weigh the cooled mixture; Dissolve the acetate fiber or the triacetate fiber in the mixture after weighing; Separate the core-sheath type low-melting-point polyester composite fibers from the dissolved mixture; Calculate the mass percentage of the core-sheath type low-melting-point polyester composite fiber in the mixture; The specific method for dissolving the acetate fiber or triacetate fiber in the weighed mixture is as follows: the weighed mixture is placed in an Erlenmeyer flask, 100 ml of 20% hydrochloric acid solution is added for every gram of the mixture, and then the Erlenmeyer flask is placed in a water bath shaker and shaken; the Erlenmeyer flask is placed in the water bath shaker at 78°C~82°C and shaken for 20 minutes or the Erlenmeyer flask is placed in the water bath shaker at 68°C~72°C and shaken for 40 minutes.

2. The quantitative analysis method for a mixture of polyester composite fibers and acetate fibers as described in claim 1, characterized in that, The mixture is dried in an oven at a temperature of 102°C to 108°C.

3. The quantitative analysis method for a mixture of polyester composite fibers and acetate fibers as described in claim 1, characterized in that, The mixture is cooled in a dryer equipped with silica gel.

4. The quantitative analysis method for a mixture of polyester composite fibers and acetate fibers as described in claim 1, characterized in that, The mixture was weighed within 2 minutes of cooling.

5. The quantitative analysis method for a mixture of polyester composite fibers and acetate fibers as described in claim 1, characterized in that, The specific method for separating the core-sheath type low-melting-point polyester composite fibers from the dissolved mixture is as follows: the liquid is drained by suction using a dry glass core crucible of known mass or filtered using a filter screen.

6. The quantitative analysis method for a mixture of polyester composite fibers and acetate fibers as described in claim 5, characterized in that, The separated core-sheath type low melting point polyester composite fiber needs to be washed at least 3 times with a 20% hydrochloric acid solution at 78°C~82°C, then washed at least 4 times with water at 78°C~82°C, then neutralized at least 2 times with a dilute ammonia solution, and finally washed thoroughly with water.

7. The quantitative analysis method for a mixture of polyester composite fibers and acetate fibers as described in claim 1, characterized in that, When calculating the mass percentage of the core-sheath type low-melting-point polyester composite fiber in the mixture, the test result is expressed as the average of two tests. If the absolute difference between the results of the two tests is greater than 1%, a third test should be conducted, and the test result is expressed as the average of the three tests.

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