Fabric Wrinkle Resistance Testing

Fabric wrinkle resistance testing mainly conducts scientific testing and analysis on wrinkle recovery angle, wrinkle recovery rate, appearance smoothness grade, crease persistence, bending stiffness and hysteresis moment, and tensile recovery performance, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Wrinkle recovery angle (WRA): This is the core indicator for evaluating the wrinkle resistance of the fabric, used to measure the ability of the fabric to recover to the original state when the external force is released after being creased by the external force. It is specifically divided into the immediate elastic recovery angle and delayed elastic recovery angle. During the testing, the warp, weft and total wrinkle recovery angles are usually recorded. The larger the angle, the better the wrinkle recovery performance of the fabric.

Wrinkle recovery rate: This indicator characterizes the wrinkle resistance by calculating the percentage of the recovered dimensions to the original dimensions of the fabric after being creased by the force. It not only reflects the final state of the recovery of the fabric, but also can reflect the speed of the recovery process, and is commonly used for comparing the wrinkle resistance persistence effects of the different fabrics or finishing processes.

Appearance smoothness grade (AATCC standard): This item evaluates the surface smoothness and the wrinkle retention degree of the fabric after the domestic washing or commercial washing and drying through the subjective visual evaluation. The rating adopts the comparison with the standard sample photos, usually divided into grades 1-5. Grade 5 indicates no wrinkles and completely smooth, and grade 1 indicates serious wrinkles.

Crease persistence: Mainly for the garments that need to maintain the creases (such as the suit trousers), testing the retention ability of the crease after the fabric forms the crease under pressure and undergoes a certain number of washes or wearings. This reflects the characteristics of the fabric to resist the recovery and maintain the shaping effect under the specific conditions.

Bending stiffness and hysteresis moment: Tested through the equipment such as the fabric style tester. The bending stiffness reflects the ability of the fabric to resist the bending deformation, and the hysteresis moment reflects the energy loss in the bending deformation. The smaller the hysteresis moment, the stronger the ability of the fabric to recover to the original state after the bending deformation, indirectly characterizing its wrinkle resistance.

Tensile recovery performance: Tests the recovery situation of the fabric after the tensile under the small load, including the elastic recovery rate and plastic deformation rate. The fabric with the low plastic deformation rate is not easy to produce the permanent wrinkles after the small-amplitude stretching in the daily wearing, and is directly related to the wrinkle resistance.

Testing Scope

Woven fabrics: Including the natural fibre fabrics such as the cotton, flax, silk and wool, synthetic fibre fabrics such as the polyester and polyamide, as well as the various blended and interwoven fabrics. The wrinkle resistance mechanisms and testing emphasis of the woven fabrics of the different fibre compositions and structures are different, for example, the cotton fabrics focus on the effect after finishing, and the polyester fabrics focus on their own characteristics.

Knitted fabrics: Due to the good elasticity and extensibility of the loop structure, the wrinkle resistance testing of the knitted fabrics is different from the woven fabrics. During the testing, special attention needs to be paid to the sampling method and the way of applying the force, to avoid the loop shedding, and it is often combined with the appearance smoothness grade and tensile recovery for the comprehensive evaluation.

Finished garments: The wrinkle resistance testing is directly carried out on the ready-made garments such as the shirts, trousers and skirts, which can better simulate the actual wearing effects. The testing parts usually select the wrinkle-prone parts such as the elbows, knees and buttocks, and the methods include the appearance rating after the wearing experiment or the recovery testing after simulating the friction and squeezing of these parts.

Home and industrial textiles: Such as the bed sheets, curtains and tablecloths, whose wrinkle resistance affects the aesthetics and the convenience of care; for the industrial textiles such as the tarpaulin fabrics and transport bags, more attention is paid to the performance retention ability after the repeated folding and squeezing, and the test conditions are more severe.

Fabrics after the wrinkle resistant/non-iron finishing: This is the key object of the wrinkle resistance testing, aiming to accurately evaluate the treatment effects of the different processes such as the resin finishing, liquid ammonia finishing and nano finishing. The testing needs to pay attention to the performance comparison before and after the finishing, as well as the durability after multiple washes (DP grade).

New and functional fabrics: Including the elastic fabrics, memory fabrics and phase change material fabrics. The wrinkle resistance testing of these fabrics needs to consider their special functions, and the testing methods may need to be adjusted or supplemented, to comprehensively evaluate their comprehensive performance in the specific application scenarios.

Testing Methods

Vertical method (GB/T 3819, ISO 2313): This is the classic method for determining the wrinkle recovery angle. The specimen is folded in half and pressed for a certain time, then vertically hung, and the recovery angle is measured. This method is simple to operate with good reproducibility, and is widely used in the routine quality control of the laboratories and factories. It is the basic standard test method at home and abroad.

Horizontal method (AATCC 66): The specimen is placed horizontally, and after the creasing and pressing, the recovery angle is measured after the release. Compared with the vertical method, the horizontal method avoids the additional sagging of the specimen due to its own weight, and the results may be slightly different. Some standards and customer requirements will specify the horizontal method for the testing.

Appearance method (AATCC 124, GB/T 13769): This is a subjective rating method. After the fabric specimen is washed and dried according to the specified procedures, under the standard light source and observation conditions, the comparison with the standard sample photos is carried out, rating its appearance smoothness grade. This method simulates the actual use situation, with the intuitive results.

Mechanical simulation method: Equipment such as a Martindale abrasion tester or random tumble pilling box is used to carry out the timed friction, squeezing and other mechanical actions on the specimen, simulating the creasing process in the actual wearing, and then combined with the appearance method or the wrinkle recovery angle method for the quantitative or qualitative evaluation, with the results of more practical reference value.

Wearing experiment method: It belongs to the actual application evaluation. The testers are allowed to wear the specific garments within the specified time, or the specific parts of the garments are subjected to the specified times of friction and sitting pressure, and then multiple raters rate the creasing situation of the various parts of the garments against the standards, taking the average value. It is the most real evaluation method, but takes a long time.

Dynamic drape crease testing method: The image processing technology is used to test the number, depth and uniformity of the creases formed by the fabric in the dynamic rotating drape state, thereby evaluating its resistance to the drape creases. This method is particularly suitable for evaluating the fabrics that naturally crease due to their own weight during use, such as the skirts and curtains.

Testing Standards

Domestic Standards:

1. GB/T 3819, Textiles — Determination of the recovery from creasing of a folded specimen by measuring the angle of recovery

2. GB/T 13769, Textiles — Test method for assessing the appearance smoothness of fabrics after washing

3. GB 18401-2010, National general safety technical code for textile products

4. GB/T 3920-2024, Textiles — Tests for colour fastness — Colour fastness to rubbing

International Standards:

1. ISO 2313, Textiles — Determination of the recovery from creasing of a folded specimen by measuring the angle of recovery

2. AATCC 66, Wrinkle recovery of woven fabrics: Recovery angle

3. AATCC 124, Appearance of fabrics after repeated home laundering

4. ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and elongation at maximum force using the strip method

5. ISO 105, Textiles — Tests for colour fastness

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Wrinkle recovery angle tester: The core equipment, used for the vertical and horizontal method testing. The instrument usually includes a specimen clamping device, pressing device, angle measuring disc or digital angle sensor. The advanced models are equipped with the automatic timing, loading and reading systems, and can be connected to the computer for the direct output and processing of the test data, ensuring the precise and efficient results.

Standard washing and drying equipment: Used for the pre-treatment of the appearance method testing, including the standard automatic washing machines (such as the AATCC standard washing machine) and tumble dryers. The equipment must be able to precisely control the washing water temperature, water level, agitation speed, drying temperature and time, to ensure the uniformity of the test conditions and the comparability of the results.

Standard light source cabinet: When evaluating the appearance smoothness grade of the fabric, it provides the stable, uniform and glare-free D65 standard light source environment for the rating personnel. The inner wall of the cabinet is neutral grey, which can effectively eliminate the interference of the ambient light, ensuring the objective and accurate rating results and reducing the human visual errors.

Fabric style tester/mechanical property tester: Such as the KES-F and FAST systems. By testing the mechanical properties such as the bending, shear, tensile and compression of the fabric, the multiple indicators such as the bending stiffness and hysteresis moment are obtained, comprehensively analysing and predicting the wrinkle resistance of the fabric from the mechanical essence level. It is suitable for the in-depth research and product development.

Image analysis system: Composed of a high-resolution digital camera, uniform light source and image processing software. It is used to photograph the wrinkled fabric surface, and through the software algorithms, the three-dimensional morphological parameters such as the number, depth and contour tortuosity of the wrinkles are quantitatively analysed, realizing the objectification and digitization of the wrinkle resistance evaluation.

Environmental temperature and humidity control chamber: Since the temperature and humidity have a significant influence on the mechanical properties, especially the recovery of the fibres, the standard tests (such as GB/T 3819) require the specimen conditioning and testing under the standard atmospheric conditions (such as 20±2 ℃ and 65±4% RH). The constant temperature and humidity chamber provides the stable test environment for this purpose, and is the essential condition for obtaining the reliable data.