A method of testing the wear of the crotch of a pair of jeans

Abstract

The present application relates to the field of textile detection, in particular to a kind of detection method for testing the wear of the crotch of jeans, the method includes the following steps: crotch sample preparation, wear test and evaluation, tensile test and evaluation.The present application simulates the wear of the crotch structure of jeans, and further carries out tensile test after wear, more truly simulates the wear and tear of the crotch of jeans in the actual wearing process of jeans, and can realize the standardized batch detection of the wear detection method of the crotch of jeans, so as to better control the quality before the clothing is put on the market.

Description

Technical Field

[0001] This invention relates to the field of textile testing, specifically to a method for testing the wear and tear of the crotch area of ​​jeans. Background Technology

[0002] Jeans, with their durability, consistent fit, and versatility, have become a mainstream garment for everyday wear. However, the crotch area is the most vulnerable and prone to damage during actual wear. Walking, squatting, leg lifting, and changing sitting postures cause repeated friction, stretching, and bending in the crotch area, making it a major factor affecting the lifespan of jeans and a primary source of consumer complaints.

[0003] Currently, textile abrasion resistance testing mostly uses common testing methods such as Martindale abrasion, flat abrasion, and flexural abrasion. These methods only perform single-plane friction tests on flat fabrics and cannot accurately reproduce the actual wear and tear conditions of the crotch area of ​​jeans. First, traditional testing involves uniform friction on a flat surface with uniform force, while the crotch area of ​​jeans has a three-dimensional curved structure, and the actual force includes complex loads such as friction, tension, torsion, and folding, resulting in significant differences in the working conditions between the two. Second, existing equipment uses a fixed friction method and a single motion path, which cannot simulate the staggered reciprocating friction motion generated by the alternating opening and closing of the human legs, resulting in low simulation accuracy. Finally, conventional abrasion resistance testing can only evaluate the overall abrasion resistance performance of the fabric and cannot specifically characterize the abrasion resistance level of the weak crotch area. This often leads to situations where the laboratory test results are satisfactory, but the fabric wears out within a short period of actual wear, resulting in poor consistency between test data and actual use.

[0004] Currently, the industry lacks standardized and specialized methods for testing the crotch abrasion resistance of jeans, with companies relying heavily on manual fittings to assess this performance. However, manual fittings suffer from drawbacks such as long testing cycles, high costs, significant human error, unquantifiable data, and poor repeatability, failing to meet the industrial testing needs of new product development, batch quality inspection, and factory sampling. The lack of unified and precise testing standards and methods results in inconsistent crotch abrasion resistance quality across the market, easily leading to quality disputes and hindering quality control and standardization within the denim apparel industry. Summary of the Invention

[0005] In view of the above-mentioned technical background, the present invention provides a detection method that can more realistically simulate the wear and tear of actual clothing.

[0006] A method for testing the wear and tear of the crotch area of ​​jeans.

[0007] Experimental instruments: Color fastness tester for rubbing or Martindale abrasion tester.

[0008] The test method includes the following steps: Step 1: Sample Preparation: Overlap the denim fabric to be tested with three or more layers and sew two seams along the warp direction to simulate the crotch seam of jeans; specifically, the following two methods are available: 1. Fold the denim fabric to be tested twice toward the reverse side of the fabric along the warp edge, and then fold it outward once. Each fold should be 2-3cm. Sew two seams along the warp direction.

[0009] 2. Place the two denim fabrics face to face, fold them along the weft direction, sew them together along the warp direction, and sew the crotch area of ​​the denim fabric to resemble jeans.

[0010] Furthermore, the parameters for the stitching are as follows: It is made of 100% polyester core-spun yarn (long core, short fiber covering), with a linear density of (45±5) tex; Distance between two sutures: 3mm; Stitch density (50±2) stitches / 100mm; The metric machine needle is number 90 and has a diameter of 0.90mm.

[0011] Step 2: Wear test and evaluation. Use a Martindale abrasion tester or a dyeing rubbing fastness tester to test the abrasion resistance of the sample, record the number of broken warp yarns (m), and evaluate the wear. Based on the evaluation, determine whether the experiment is over or proceed to Step 3.

[0012] Further wear assessment is as follows: If m≤2 pieces, the wear resistance grade of the sample is deemed qualified and the test is stopped; If 2 < m ≤ 8 pieces, the wear resistance grade of the sample is preliminarily qualified, and step three is performed. If m > 8, the wear resistance grade of the sample is deemed unqualified, and the test is stopped.

[0013] Step 3: Tensile testing and evaluation: The wear specimens from Step 2 are tested using a tensile testing machine. Sample installation: Secure both ends of the sample (i.e., the warp ends of the fabric) with the clamping parts, start the testing instrument, move the movable clamping device, stretch the sample until it breaks, and record the breaking strength F (in Newtons N); and perform wear tensile evaluation: If F > n N, the wear resistance grade of the sample is deemed qualified, and the test ends. If F ≤ n N, the wear resistance grade of the sample is deemed unqualified, and the test ends.

[0014] In some embodiments, different numbers of friction cycles are set in step two for different fabric structures, yarn specifications, and thicknesses.

[0015] This testing method allows for a relatively realistic simulation of the actual wear and tear on the crotch area of ​​jeans in a laboratory setting. Existing denim abrasion resistance tests only test the friction of the flat surface of the fabric itself, without simulating the crotch structure of jeans for separate testing. This deviates from the actual wearing process of jeans, and the existing test standards are difficult to truly simulate the wear and tear of the special folding structure of the crotch of jeans. Meanwhile, existing tensile tests for denim fabrics only cover tearing or seam tensile strength, and there are currently no tests for tensile strength after wear, let alone tests for tensile strength after wear in the crotch area of ​​jeans. This invention simulates the wear and tear of the crotch structure of jeans and further conducts tensile tests after wear, realistically simulating the wear and tear and stretching of the crotch of jeans during actual wear. It enables a standardized batch testing method for crotch wear detection in jeans, allowing for more realistic quality control before garments are released to the market. Detailed Implementation Example 1

[0016] A method for testing crotch wear in jeans Step 1: Making the crotch sample. Fold the denim fabric to be tested twice along the warp edge towards the reverse side of the fabric, and then fold it outward once. Each fold is 2-3cm. Then sew it together. Sew the folded denim along the folded edge using the following thread parameters: It is made of 100% polyester core-spun yarn (long core, short fiber covering), with a linear density of (45±5) tex; Distance between two sutures: 3mm; Stitch density (50±2) stitches / 100mm; The metric machine needle is number 90 and has a diameter of 0.90mm.

[0017] In this embodiment, four samples were prepared and labeled 1#, 2#, 3#, and 4# respectively.

[0018] Step Two: Wear Test and Evaluation: A color fastness tester for dyeing and rubbing was used. The parameters are as follows: Vertical pressure of the friction head: (12.9±0.2) N; Friction head size: 19mm × 25.4mm; Operating speed: (60±3) times / min; Friction head stroke: (104±3)mm; Test temperature: (20±2℃) Humidity: (65%±4); Abrasive material: the same fabric as the denim to be tested.

[0019] Note: Theoretically, using denim fabric, the same as the test sample, as the abrasive can more accurately reflect the actual wear. However, considering the laboratory testing stage, in order to improve testing efficiency, accelerated destruction can be used to test its abrasion resistance. Therefore, this method also uses wool abrasive with a higher coefficient of friction.

[0020] Set the number of rubbing cycles to 1000, 2000, 2000, and 3000 for #1, #2, #3, and #4 respectively. When installing the sample, place the sample face down so that the face is in contact with the abrasive during the test. Start the dyeing rubbing fastness tester to begin the test.

[0021] The wear condition of the samples that have undergone friction testing is examined under a D65 standard light source and evaluated.

[0022] The test results are evaluated according to the table below:

[0023] Table 1: Wear Test Evaluation Criteria In step two, the wear and tear of #1, #2, #3, and #4 is as follows:

[0024] Based on the wear condition, #2 and #4 were determined to be unqualified, and the test ended. #1 and #3 continued to step three.

[0025] Step 3: Remove samples #1 and #3 after the above steps. Clamp the two ends of the sample parallel to the seam using the clamping part of the tensile testing machine. Start the tensile testing machine, set the tensile force increase rate, and continue until the sample breaks. Record the value at which the sample breaks, and rate the sample according to the value. Stop the test. The test results are evaluated according to the table below:

[0026] Table 2: Evaluation Criteria for Wear and Tensile Test The test data are as follows:

[0027] Referring to Table 2 above, determine whether #1 is wear-resistant or #3 is not wear-resistant.

[0028] Example 2 A method for testing crotch wear in jeans Step 1: Making the crotch sample. Place the two denim fabrics to be tested face to face, fold along the weft direction, sew along the warp direction, and sew the crotch of the sample to resemble denim jeans, so that the right sides of both sample fabrics are facing outwards.

[0029] In this embodiment, five test samples were selected and labeled as 5#, 6#, 7#, 8#, and 9# respectively.

[0030] Step 2: Wear test and evaluation. The wear resistance of the samples is tested using a Martindale abrasion tester. Parameter settings: Pressure selection: 9 kPa, Temperature: (20±2℃) Humidity: (65%±4) Abrasive: Wool abrasive Friction cycles: Set 8000, 12000, 12000, 12000, and 15000 cycles for samples #5, #6, #7, #8, and #9 respectively. When installing the sample, place the sample face down so that the face is in contact with the abrasive during the test. Start the Martindale abrasion tester to perform abrasion resistance test on the sample.

[0031] Wear evaluation: The wear condition of the rubbed sample was examined under a D65 standard light source and evaluated with reference to Table 1.

[0032] The wear condition of #5, #6, #7, #8, and #9 is as follows:

[0033] Refer to Table 1 for preliminary judgment. 5# is qualified, so the test is stopped; 6# and 7# are determined to be unqualified, so the test ends; 8# and 9# continue to step three.

[0034] Step 3: Tensile testing and evaluation. A tensile testing machine is used to test samples #5, #7, #8, and #9 from Step 2: Sample installation: The two ends of the sample (i.e., the warp ends of the fabric) are fixed using the clamping parts. The testing machine is started, and the movable clamps are moved to stretch the sample until it breaks. The breaking strength F (in Newtons N) is recorded. The test results and ratings are as follows:

[0035] Referring to the wear tensile test evaluation criteria in Table 2, #5, #8, and #9 are deemed qualified.

[0036] In this application, tensile tests without wear were also conducted simultaneously (using the corresponding sample fabrics of the same type) on the tested fabric samples #1, #2... #9 for comparison. The specific data are as follows:

[0037] This demonstrates a significant change in breaking strength before and after friction. Previously, the industry only tested the breaking strength of denim fabric, lacking specific simulation tests for the crotch area of ​​jeans. This created a gap in quality control for the actual market launch of the product. Therefore, this application realistically simulates the wear and stretch test of the crotch area of ​​jeans, enabling more comprehensive quality control before product release.

[0038] The above embodiments are only for further illustrating the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-creative adjustments made based on the technical solutions of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for testing the wear and tear of the crotch area of ​​jeans, characterized in that: Includes the following steps Step 1: Crotch Sample Preparation: Overlap the denim fabric to be tested with three or more layers, ensuring at least one right side of the fabric faces outwards. Sew two seams along the warp direction to simulate the crotch seam of jeans. Step 2: Wear test and evaluation: Use a Martindale abrasion tester or a dyeing rubbing fastness tester to test the abrasion resistance of the sample; record the number of broken warp yarns (m), evaluate the wear, and determine whether the test ends or proceeds to step 3 based on the wear evaluation; Step 3: Tensile Testing and Evaluation: Perform tensile testing using a tensile testing machine on the worn specimen from Step 2. Sample installation: Fix both ends of the sample with the clamping part, start the testing instrument, move the movable clamp, stretch the sample until it breaks, record the breaking strength F (in Newtons N), and perform wear tensile evaluation. If F > n N, the wear resistance grade of the sample is deemed qualified, and the test ends. If F ≤ n N, the wear resistance grade of the sample is deemed unqualified, and the test ends.

2. The method for testing crotch wear of jeans according to claim 1, characterized in that: The sewing parameters are as follows: It is made of 100% polyester core-spun yarn (long core, short fiber covering), with a linear density of (45±5) tex; Distance between two sutures: 3mm; Stitch density (50±2) stitches / 100mm; The metric machine needle is number 90 and has a diameter of 0.90mm.

3. The method for testing crotch wear of jeans according to claim 1, characterized in that: The crotch area sample was prepared using the following method: Fold the denim fabric to be tested twice toward the reverse side along the warp edge, then fold it outward once, each fold being 2-3cm. Sew two seams along the warp direction.

4. The method for testing crotch wear of jeans according to claim 1, characterized in that: Step two involves using a color fastness tester for rubbing to test the abrasion resistance of the sample. The parameters are as follows: Vertical pressure of the friction head: (12.9±0.2) N; Friction head size: 19mm × 25.4mm; Operating speed: (60±3) times / min; Friction head stroke: (104±3)mm; Temperature: (20±2℃) Humidity: (65%±4); Abrasive: Wool abrasive or denim of the same type as the test sample.

5. The method for testing crotch wear of jeans according to claim 1, characterized in that: Step two involves using a Martindale abrasion tester to perform abrasion resistance testing on the samples, with the following parameters: Pressure selection: 9 kPa; Temperature: (20±2℃), Humidity: (65%±4); Abrasive: Wool abrasive or denim of the same type as the test sample.

6. The method for testing crotch wear of jeans according to claim 1, characterized in that: The wear evaluation in step two is as follows: If m≤2 pieces, the wear resistance grade of the sample is deemed qualified and the test is stopped; If 2 < m ≤ 8 pieces, the wear resistance grade of the sample is preliminarily qualified, and step three is performed. If m > 8, the wear resistance grade of the sample is deemed unqualified, and the test is stopped. The wear and tensile evaluation in step three is as follows: If F > 100 N, the wear resistance grade of the sample is deemed qualified, and the test ends. If F≤100 N, the wear resistance grade of the sample is deemed unqualified, and the test ends.

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