Creases are folds or bends in fabric that may occur unintentionally during textile processing. They happen when fibers are stretched beyond their elastic limit, resulting in tensile, compressive, flexing, and torsional stresses. The ISO 2313 standard crease recovery test is used to determine the crease recovery angle.
What is Crease Recovery in Textile?
The ability of the fabric to prevent the formation of wrinkles or creases on the fabric’s surface during various uses or processes is called the crease recovery (CR) of the fabric. The crease resistance of the fabric is expressed in terms of the crease recovery angle (CRA).
In simple words, CR is a fabric’s capability to recover to its original condition. It is the measure of the fabric’s resistance to wrinkles.
Crease recovery is one of the most important appearance-retention properties considered by the modern textile industries, especially for export garments, school uniforms, dress shirts, trousers, and home textiles. Maximum crease recovery ensures that the garment will look fresh, smooth, and professional even after repeated home laundering, tumble drying, and daily usage. Almost all the textile buyer evaluates this property before the approval of bulk production and making it essential for quality control teams.
Sample explanation of crease recovery
In practical terminology, crease recovery predicts how neat a textile material will look after sitting, folding, packing, or bending at any angle during wear. Those fabrics which having high CRA maintain their shape and drape better, which reduces iron requirement and increases comfort. This is the main reason for using wrinkle-resistant finishes, resin treatment during wet processing, and fiber-blend modification are designed to improve crease recovery in cotton and blends.
What Is a Crease in Fabric?
If a fabric folds so severely that it cannot recover itself in its original condition, it is called a crease.
Why Creases Are Considered Textile Defects
During quality inspection, permanent creases are classified as visual defects because they decrease the overall value of the garments, and creases can weaken the fibers due to repeated stress on the same point, which makes the fabric highly susceptible to abrasion and tearing. Almost all the apparel brands perform a crease evaluation test before approving the lot of finished materials.
Why Does Crease Happen?
Creases happen because, in the folding area of a fabric where a crease shows, the fibers’ stretches are beyond their elastic limit. The fiber does not return to its previous position, causing crease formation.
The place on the cloth where the fabric folds fibers are bent. One side of the fiber is stretched, and the other is compressed and flexed. Torsional stresses are also applied to the fiber because the yarn combines twisted fiber.
When yarn is stretched, it faces torsional stresses due to the inside fibre twisting. So, the crease effect results from all combined tensile, compressive, flexing, and torsional forces.
Why Do Creases Form? (Causes & Fiber-Level Mechanism)
Crease formation is influenced due to mechanical forces, environmental factors such as temperature and moisture content, type of fiber, and tightness of the weave, etc. Cellulosic fabrics, such as cotton and viscose, having high moisture regain, crease more easily than hydrophobic fibers such as polyester. Many other factors, such as low-twist yarn, loose woven structure, and unfinished fabric, show deeper creasing.
What is Crease Resistance?
The resistance of a fabric to creasing is called crease resistance. For example, cotton fiber has very low crease-resistance, while polyester has better wrinkle resistance than cotton.
Crease resistance is a key achievement parameter in textile finishing. It helps manufacturers to decide whether a fabric needs resin finishing, silicon softening, or durable-press treatment. Fabrics that are used in professional clothing, such as work-wear, uniforms, and home furnishing, must have strong crease resistance to ensure long-lasting appearance and satisfaction of the customer.
How to measure Crease?
The ability of a fabric to recover from a wrinkle is called crease recovery, which is measured by the crease recovery angle.
Wrinkle recovery varies from 0 – 180 degrees. CRA is zero if both sides of the folded fabric remain stuck together. If the fabric recovers to its original condition and gets the full straight position, then the crease recovery angle is 180.
Warp vs Weft Crease Recovery Values
During testing conditions, the values of both warp and weft CRA are noted separately because the behavior of the fabric is dependent on direction. In woven fabrics, the warp yarns are generally tighter and stronger compared to the weft yarn, giving a different recovery angle. On behalf of the separated values of the warp and the weft, the lab technician calculates both values to represent the overall crease recovery rating, which represents the fabric’s wrinkle performance.
Factors Affecting Crease Recovery
The CR property of fabrics depends on the following factors.
- Fiber properties
- Yarns structure
- Fabric structure
- Any finish or chemical treatment
Yarn twisting level, cross-section of the fiber, GSM, blend ratio, moisture regain, finishing processes, calendaring, and heat-setting also affect crease recovery. Among all of the textile fibers, polyester exhibits excellent crease recovery due to its hydrophobic nature, while viscose, cotton, and rayon show poor recovery due to their hydrophilic nature and require chemical treatment to improve their crease recovery. Blended fibers such as cotton-polyester offer improved crease behavior due to its thermoplastic nature if the synthetic fibers.
AATCC 66ISO 2313 Crease Recovery Tester YG (B) 541EAATCC 66 / ISO 2313 Crease Recovery Test
A crease recovery tester evaluates textile wrinkle resistance.
Let’s look at the apparatus items we would require during testing.
AATCC 66/ISO 2313 Crease Recovery Tester YG (B) 541E
Apparatus
- Crease recovery tester
- Specimen template
- Loading plates
- Stopwatch
- Scissor
- Marking pen
- Fabric specimen
- Measuring scale
Many advanced testers, such as YG(B)541E, contain calibration weights, an adjustable sample clamp, thermal sensors, and an automatic lifting mechanism, which help the technician to ensure consistency, especially when testing bulk samples for production lots.
Specimen Preparation
Specimen PreparationFor textile crease recovery measurement, the test specimens are prepared separately in directions, warp, and weft. Ten specimens from each direction are prepared.
The specimens are measured using a scale and then cut with scissors. In textile testing, this is a good way to take more samples to avoid variation.
Before preparing the specimens, the warp and weft directions are identified carefully with a magnifying glass. The specimen size is kept at 2 inches × 1 inch. A technician can also use a marking template to prepare the test specimens.
The most critical step is the preparation of the testing specimen. A slight deviation in size or improper grain alignment can vary or causing inaccurate reading. Therefore, the standard testing atmospheric conditions must be ensuring before testing as per ISO and AATCC requirements.
Let’s look at the fabric wrinkle resistance testing procedure.
Procedure
The warp and weft way specimens are placed separately. First, 05 warp way specimens are folded in the middle of the length. These five specimens are folded face-to-face with the fabric.
Now, the other 05 remaining warp-way specimens are folded back to back. These specimens are also folded in the middle of their length of the specimens.
The specimen loading device consists of a loading plate and a pressing plate. The specimen is placed between two pressing plates.
The above process is repeated for weft-way specimens as well. Now, start testing the warp specimens one by one. The folded sample is placed between the base plate and the pressing plate.
Take a sample with a folded size of 20 × 15 millimeters. Fix twice 20 × 40 millimeters. Longitude and latitude both take 05 pieces.
The sample is folded in half to crease it. The folded sample is placed between the glass slides, and weight is applied to them for a specific period. The weight and time depend upon the customer’s requirements.
Turn on the power switch. Open the testing software. Test method vertical method. Input sample information. Sample 01, quantity 10, temperature 20 C, humidity 65%, set it, save and confirm. Press Start.
Set ParametersThe instrument will run automatically, and the assembly will start when the rotation is over. Install the fixed part of the sample on the gripper. Fold the foldable part to cover the plating. The other samples will be installed in the same way.
Install Sample in Machine GripperAfter the installation is complete, the instrument will start the test automatically. After the sample has been subjected to pressure for 5 minutes, the instrument will remove the hammer automatically.
Specimen subjected to pressure to develop crease5 minutes after unloading the sample. The instrument will automatically measure the folding trace recovery angle. The experimental results are obtained after the completion of the test.
Click the file to export the data.
Crease Recovery Test ResultsPrecautions
The below precautions must be followed during testing.
- The warp and weft directions should be identified precisely.
- The dimensions of each specimen should be accurate.
- The fabric should be conditioned for 04 hours under atmospheric conditions.
- Two to three inches of the fabric should be removed from both selvages before specimen preparation.
- The loading time should be recorded precisely. The Darong tester gives results automatically on the on-screen display.
Note
The dimensions of the specimen, pressing load, and time may be varied according to the standard system followed during testing.
Conclusion
The ability of the fabric to prevent the formation of wrinkles or creases on the fabric’s surface during various uses or processes is called the crease recovery of the fabric. The crease resistance of the fabric is expressed in terms of the crease recovery angle (CRA).
Crease recovery testers (CRT) measure textile wrinkle recovery. They are manual or automatic. Darong offers automatic CRT, which gives results in digital form. You can print the results with graphs and numeric values.
FAQs
What is meant by the crease in textile?
Creases are a fold or bend in the fabric, which may occur unintentionally during textile processing.
Why does the wrinkle effect come on fabric?
It happens in a fabric when fibers are stretched beyond their elastic limit, resulting in tensile, compressive, flexing, and torsional stresses.
Which standard is called the wrinkle recovery test?
ISO 2313 standard is used to determine the crease recovery angle.
How do we measure fabric crease resistance?
The ability of a fabric to recover from a wrinkle is called crease resistance, which is measured by the crease recovery angle (CRA).
What is the maximum and minimum range of CR values?
Wrinkle recovery varies from 0 – 180 angle. CRA is zero if both sides of the folded fabric remain stuck together. If the fabric recovers to its original condition and gets the full straight position, then the crease recovery angle is 180.
Which factors affect the CR of fabric?
The CR property of fabrics depends upon Fiber properties, yarn structure, Fabric structure, and any finish or chemical treatment.
What is the difference between crease resistance and crease recovery?
A fabric’s resistance to creases is called crease-resistance, while its capability to recover to its original condition is called crease recovery.