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Home > News > Industry NewsThe textile and apparel industry is closely related to our daily lives. Textile testing covers many items, and with rapid economic development, testing methods are constantly being updated. Below, let's take a look at these essential tests.
1) Purpose: To determine the dimensional stability of woven or knitted fabrics after repeated household machine washing.
2) Principle: Before washing, markings are made on the test specimen. The dimensional change of the specimen is determined by measuring the changes in these markings after washing.
3) Process: Select the washing and drying methods, cycles, and number of drying repetitions based on the fabric type and customer requirements. Add standard detergent and an appropriate water level, then proceed with washing and drying. Finally, record the test results.
1) Main Items:
Yarn count, fabric density, fabric weight, tensile strength, tear strength, seam slippage, seam strength, burst strength, abrasion resistance, pilling resistance, etc.
2) Detailed Explanation:
Yarn Count: Refers to the thickness of the yarn. The most commonly used system is the English cotton count, denoted as Ne. Its definition is: the number of 840-yard hanks per pound of cotton yarn at the official moisture regain of 9.89%.
Fabric Density: The number of yarns per inch.
Fabric Weight: Ounces per square yard or grams per square meter.
Tensile Strength: The force required to stretch a fabric specimen of a specific size to its breaking point, using a tensile strength tester at a constant rate of extension. There are two methods for tensile strength testing: the grab method and the strip method. The specific method is chosen based on different testing standards and customer requirements.
Tear Strength: A specimen of a specific size is clamped in a tear strength tester. A cut is made in the center to determine the tear direction. The tester uses a pendulum drop mechanism to tear the specimen from the cut. The force required is the measured tear strength.
Seam Slippage: A fabric specimen of a specific size is folded and stitched along the width direction. After cutting at a certain distance from the seam, a tensile strength tester is used to apply a constant rate of extension until a specific seam opening width is reached, or to measure the opening width at a specific force. This measured force or width is the seam slippage. There are two methods: measuring force at a specific opening and measuring opening at a specific force. The specific method is chosen based on testing standards and customer requirements. Seam slippage is typically only tested on woven fabrics.
Seam Strength: Similar to seam slippage. A fabric specimen is folded, stitched along the width direction, and cut at a distance from the seam. A tensile strength tester applies a constant rate of extension until the seam breaks. The force required is the seam strength. Seam strength can be tested simultaneously with seam slippage and is generally only performed on woven fabrics.
Burst Strength: The force required to rupture a planar fabric by applying an expanding, distending force at a right angle to the fabric plane under specific conditions. This force is the burst strength.
Abrasion Resistance: Under a known pressure, a specimen mounted on a specimen holder is rubbed against a standard abrasive fabric with a specific trajectory under a specific pressure. The test continues until the specimen shows the number of broken yarns or holes specified by the customer. The number of rubbing cycles completed at the end of the test is the recorded abrasion resistance value.
Pilling Resistance: The fabric is tumbled and rubbed under specific conditions for a certain period. The surface of the fabric is then observed for fuzzing and pilling. Pilling refers to the formation of small balls of entangled fibers standing on the fabric surface. Fuzzing refers to the roughening and/or raising of surface fibers, leading to a change in the fabric's appearance. Pilling and fuzzing are assessed by comparison with standard rating photographs or the original untreated sample.
1) Main Items:
Colorfastness to washing, dry cleaning, rubbing, light, perspiration, water, chlorine bleach, non-chlorine bleach, hot pressing (ironing), etc.
2) Basic Content:
Colorfastness to Washing: A specimen is stitched together with standard multifiber adjacent fabric, then washed, rinsed, and dried. Washing is carried out under specific conditions of temperature, alkalinity, bleaching, and mechanical action (rubbing) to obtain results in a short time. The mechanical action is achieved through a low liquor ratio and the tumbling, impacting action of an appropriate number of stainless steel balls. Finally, the standard adjacent fabric and specimen are rated using standard gray scales for colorfastness. Different test methods have different temperatures, alkalinity levels, bleaching conditions, rubbing actions, and specimen sizes. The specific method is chosen based on testing standards and customer requirements. Colors generally known to have poor wash fastness include turquoise, bright blue, black, bright red, and navy.
Colorfastness to Dry Cleaning: Similar to colorfastness to washing, but with washing replaced by dry cleaning.
Colorfastness to Rubbing: The specimen is placed on a crockmeter. Under a specific pressure, it is rubbed a specific number of times against a standard white rubbing cloth. Both dry and wet rubbing fastness tests are performed for each specimen set. The color transferred to the standard white rubbing cloth is rated using a gray scale. The resulting grade is the measured colorfastness to rubbing. Rubbing fastness requires both dry and wet tests, and all colors on the specimen must be rubbed.
Colorfastness to Light: Textiles are often exposed to light during use. Light energy can degrade dyes, causing the well-known phenomenon of "fading," which discolors colored textiles, usually making them lighter or duller, and sometimes causing a change in shade. Therefore, colorfastness testing is necessary. For light fastness testing, the specimen is exposed to sunlight (or artificial light) under specified conditions alongside blue wool standards of different fastness grades. The specimen's fading is compared to the blue wool standards to rate its light fastness. Higher-grade blue wool standards indicate greater resistance to light.
Colorfastness to Perspiration: The specimen is stitched together with standard multifiber adjacent fabric, treated in a perspiration solution, then placed between acrylic plates under a specific weight in a perspiration tester, and placed in an oven at a constant temperature. The specimen and adjacent fabric are then dried separately. Finally, the standard adjacent fabric and specimen are rated using standard gray scales for colorfastness. Different test methods have different perspiration solution compositions, specimen sizes, and testing temperatures/durations.
Colorfastness to Water: The specimen is stitched together with standard multifiber adjacent fabric, fully immersed in water under specified conditions, then placed between acrylic plates under a specific weight in a perspiration tester, and placed in an oven at a constant temperature. The specimen and adjacent fabric are then dried separately. Finally, the standard adjacent fabric and specimen are rated using standard gray scales for colorfastness. Different test methods have different specimen sizes and testing temperatures/durations.
Colorfastness to Chlorine Bleach: The fabric is washed under specific conditions in a chlorine bleach solution. The degree of color change is then assessed. This is the colorfastness to chlorine bleach.
Colorfastness to Non-Chlorine Bleach: The fabric is washed under conditions involving non-chlorine bleach. The degree of color change is then assessed. This is the colorfastness to non-chlorine bleach.
Colorfastness to Hot Pressing (Ironing): A dry specimen is covered with a cotton adjacent fabric and subjected to a heating device at a specified temperature and pressure for a specific time. The color change of the specimen and the staining of the adjacent fabric are then rated using standard gray scales. Hot pressing tests can be performed under dry, damp, or wet conditions. The specific method is chosen based on customer requirements and testing standards.
1) Main Test Items:
Formaldehyde testing, pH value testing, water repellency, oil repellency, stain release, flame retardancy, fiber composition analysis, banned azo dyes testing, etc.
2) Basic Content:
Formaldehyde Testing: Free or released formaldehyde is extracted from a specific amount of fabric using a specified method. The formaldehyde content is then calculated through colorimetric testing.
In the current market, textile products can be treated with resin finishes to improve wrinkle resistance. These resin finishing agents are often synthesized directly from formaldehyde, so fabrics treated with these resins will retain a certain amount of residual formaldehyde. Additionally, to improve colorfastness, crosslinking agents in pigment printing pastes and fixing agents used after dyeing with direct or reactive dyes can also leave residual formaldehyde on garment materials. This formaldehyde can be measured using specific test methods.
pH Value Testing: A pH meter is used to accurately measure the acidity or alkalinity of a fabric solution. The value displayed on the pH meter is the measured pH value.
Water Repellency, Oil Repellency, Stain Release Testing: These tests measure the fabric's resistance to water, oil, and stains using specific methods. They are primarily conducted on fabrics that have undergone special water/oil/stain repellent finishes.
Flame Retardancy Testing: The specimen is placed in a flame retardancy tester according to the specified procedure and ignited. The flame spread time is observed.
Fiber Composition Analysis: First, the fabric fibers are qualitatively analyzed. There are several methods for qualitative analysis, including the burn test, melting point test, hand-feel and visual inspection, and microscopic cross-sectional analysis. The microscopic cross-sectional analysis method is commonly used: fibers are sliced using a microtome, observed under a microscope, and identified based on their appearance. After identifying the fiber types, different solvents are used for quantitative analysis of the different fibers to calculate the specific composition percentages.
Banned Azo Dyes Testing: This is one of the most important quality control items in international textile and apparel trade and is a fundamental quality indicator for ecological textiles. Currently, it is primarily analyzed using gas chromatography. Azo dye testing is divided into three methods based on material: textiles (excluding polyester and real leather), polyester, and leather (real leather). Therefore, it is essential to provide the product's fiber composition when conducting azo dye testing.
