The advancement of modern technology across all industries, especially in textiles, has made material control increasingly indispensable. From the reception of raw materials to the production of the final product, ensuring quality at every stage of the process is fundamental.
Specific Properties of Quality Control
1. Geometric Properties
Fabric Weight (Grammage)
Fabric weight, or grammage, is a key parameter as it determines the amount of material used in its manufacture. It is expressed in grams per square meter and can also be converted into weight per linear meter.
The test to determine fabric weight is straightforward: a balance and a circular cutter are used to obtain a 10 x 10 cm sample, which is weighed, and the result is multiplied by 100 to obtain the weight per square meter. This procedure follows standard UNE 12127.
Fabric Density
Fabric density is measured in threads and picks per centimeter. It is determined by direct observation and counting with a thread counter, an instrument that magnifies the view and delimits the measured length.
Weave Patterns
The weave pattern defines the interlacing of warp and weft threads in woven fabrics. Its correct execution is verified by direct observation with a thread counter. Applicable standards are UNE 40017 and UNE 40161.
Dimensional Stability
For fabrics and garments that require dimensional stability after washing, a test is performed in a common washing machine or specific equipment such as the Wascator.
50 cm are marked in the warp and weft directions, washed at 40°C with a standard program, and after drying, the length is measured again. The variation, expressed as a percentage, indicates the fabric’s stability (maximum allowed: 3%).
Fabric Deformation and Distortion
Standard UNE 40.079 describes methods for evaluating deformations between warp and weft, which should form a right angle. The following defects may occur:
- Warp or weft bowing: threads are not straight.
- Double bowing: the weft bow changes direction in different areas.
- Skew: the warp and weft do not form a right angle.
Measurement is performed with a ruler and square on a sample conditioned for 24 hours in a controlled atmosphere.
In these cases, on the sample or piece previously conditioned for at least 24 hours in the normal test atmosphere, the maximum amplitude of the deformation is determined using a ruler and square graduated in centimeters and millimeters.
Figure 1 shows the operating procedure for measuring bowed warp, defined as the greatest perpendicular distance between the line connecting two points 250 mm from the fabric selvedge.
Similarly, to measure the greatest perpendicular distance between the line connecting the two ends of a bowed pick and its most distant point, the graduated ruler (Figure 2) is placed across the fabric so that one of its edges aligns with the selvedges and the determined pick. The square is slid, and the maximum deflection of the aforementioned pick relative to the ruler is checked.
Double bowing is measured as the shorter side of the rectangle capable of containing the bowed pick, such that the other side of the rectangle is parallel to the line connecting the two points where the pick intersects the selvedges. Figure 3.
Skew is measured as the distance between one end of a pick and the point on the same selvedge intersected by a line from the other end of the pick and perpendicular to the warp (Figure 4), expressed as a percentage of the fabric width.
2. Mechanical Properties
Tensile Strength
This test measures the force required to break a fabric, determining its appropriate use. Its elongation under tension is also evaluated.
A dynamometer is used, which applies force until the fabric breaks. The test can be performed on the fabric itself, on seams, or for tear resistance.
Crease Resistance
Crease analysis evaluates the fabric’s ability to recover its shape after being subjected to pressure and flexing. This test follows standard UNE-EN 22313:1993.
Snagging Resistance
Performed according to ASTM 3939, especially for knitted fabrics. The fabric is placed in a cylinder that rotates in contact with a ball with points. After a determined number of cycles, it is visually compared with a standard scale, assigning a score from 1 to 5 (with 5 being the highest resistance).
3. Retentive Properties
Fabric Fastness
Lightfastness
Color resistance to sunlight (Standard UNE-EN-ISO 105 B02).
Wash Fastness
Measures color resistance to washing (Standard UNE-EN-ISO 105 C06).
Rubbing Fastness
Evaluates color resistance to rubbing (Standard UNE-EN-ISO X12).
Ironing Fastness
Measures color stability at high temperatures (Standard UNE-EN ISO 105-X11).
Fastness to Water, Perspiration, Bleaching, and Dry Cleaning
Evaluated under specific standards such as UNE-EN-ISO 105 E01 and UNE-EN-ISO 105 E04.
Fastness tests are performed in a light box, where samples are compared to color standards under controlled illumination (D65).
Abrasion Resistance
Measured according to standard UNE-ENISO-12.947, determining the number of cycles required to break the fabric threads or calculate mass loss. The Martindale abrasion tester is used.
Pilling Resistance
Pilling is the formation of small balls on the fabric surface due to friction. It is evaluated with the Martindale abrasion tester according to standard UNE-EN-ISO 12945-2.
Resistance is classified on a scale from 1 to 5 (with 5 indicating no pilling formation).
4. Waterproofing and Breathability
Air and Water Impermeability
Air Permeability
Measured with a permeameter according to standard UNE-EN 9237.
Water Impermeability
Evaluates the amount of water the fabric resists before the third drop appears (Standard UNE-EN 20811).
Fastness tests are performed in a light box, where samples are compared to color standards under controlled illumination (D65).
Water Repellency
Measured with the Spray-test according to standard UNE-EN 24920, comparing the fabric with a standard.
Breathability
Resistance to water vapor passage is analyzed using the UNE EN 31092 (ISO 11092) test, evaluating the fabric’s thermal comfort.
5. Additional Properties
Thermal Insulation
Specific tests are performed to predict the thermal behavior of the fabric under different environmental conditions.
Effectiveness of Oleophobic and Hydrophobic Finishes
Water Repellency
Method 3M Test II. The water repellency value of the fabric is the highest numbered test liquid that does not wet the fabric within a 10-second period (the test liquids used are water and alcohol mixed in different proportions). A high number indicates greater repellency, evaluated with the 3M Test II method, using water and alcohol mixtures.
Oil Repellency
Standard: AATCC 118:1984. The AATCC oil repellency value of the fabric is the highest numbered test liquid that does not wet the fabric within a 30-second period (the test liquids used are hydrocarbons of different molecular weights).
Antibacterial Finish
The test follows standard ISO 20743:2007 and determines the fabric’s ability to inhibit microorganism growth.
Resistance of Laminates and Folds
Using dynamometry, the cohesion of a laminated fabric is analyzed, determining the adhesive strength between layers.
UV Resistance
The UV-Standard 801-1998 evaluates the fabric’s protection against ultraviolet radiation, considering its degradation with use.
Fire Resistance
Tests evaluate ignition, flame spread, heat emission, smoke production, and droplet detachment.
Aging in Climatic Chambers
The fabric’s behavior under temperature and humidity cycles is analyzed to evaluate dimensional stability, color changes, and gloss.
Tactile Evaluation
The Kawabata Evaluation System (KES) allows quantifying the fabric’s feel based on variables such as tension, shear, bending, compression, and surface.