Textile Testing is a process or technique to determine of different properties of textile materials with the help of testing instruments available in testing laboratory. It is very important to identify quality product. Besides, testing gives information about textile properties and helps to choose proper fabrics for intended end uses. Textile testing materials are evaluated to ensure their quality, performance, and suitability for specific applications. In this article, a few common testing procedures are explained in the following categories: basic material properties and fabric measurements, testing properties connected to mechanical strength, aesthetic appearance and maintenance, wear comfort, and safety.
Testing Material Characteristics:
Testing Basic Material Properties and Fabric Measures:
A textile can be described by its basic structure. Fabric properties are affected by fiber type and content, yarn count or number and twist, fabric thickness, fabric weight, weave or knit structure, and fabric density.
Fiber tests:
There are many characteristics that can be determined from fibers, for example, fiber length, the diameter, and the fineness of the fiber. In addition, a fiber’s crimp frequency— the length and the amplitude of the crimp—is critical because it determines fabric properties such as volume and elasticity. Tensile properties, breaking force, and elongation at break of a single textile fiber canhttps://textilelearner.net/measurement-of-yarn-unevenness/ also be tested.
Yarn tests:
When producing yarn, the aim is that the final product is as even as possible, because yarn unevenness causes problems in production and faults in products. Yarn evenness can be examined as yarn count constancy, uniformity of fiber diameter and material content, regularity of twist, and breaking force.
Basic fabric measurements:
Dimensional properties of fabrics can be determined as length, width, and thickness. Fabric length gives the distance from one end to the other when the fabric lays freely, having no wrinkles and when the fabric is in a nontensioned state. Total fabric gives tells the distance between the outermost edges of the fabric measured perpendicularly to the produced length of the fabric. Utility width leaves the selvedges, markings, and other irregularities in the edge areas out of the measurement. Fabric length is expressed in meters (m), and width is expressed in centimeters (cm). The width of the fabrics varies because there are different loom sizes and knitting machines, and different amounts of shrinkage occur in the finishing processes (ISO 22198).
Thickness gives the distance between the upper and lower surfaces of the material. It can be measured using a special tool that produces a small pressure on both sides of the fabric (ISO 5084) (Figure). Thickness is expressed in millimeters (mm).
Testing Properties Connected to Mechanical Strength:
The mechanical strength of a fabric can be examined as breaking, tearing and bursting strength, abrasion and strain resistance, and yarn distortion. The mechanical strength required by technical textiles is considerably more than that required by fabrics for normal use.
Breaking strength:
Breaking strength is the maximum tensile force that is recorded when extending a sample to its breaking point. Breaking elongation is the increase in length that occurs when the fabric breaks. The tensile force at the moment of rupture can be referred to as the tensile strength at break.
Tearing strength:
Tearing strength by a single-tear method (ISO 13937-2) explains the force that is required to continue tearing the fabric along a cut made in it. The tear force is determined in the warp (or length) and weft (or transverse) direction, and it is expressed in newtons (N).
Bursting strength:
Bursting strength expresses the amount of pressure required to rupture a fabric. There are two test methods that can be applied: the hydraulic method (ISO 13938-1) and the pneumatic method (ISO 13938-2) for determination of bursting strength and bursting distension. In the first method, a rubber diaphragm is expanded by liquid pressure until it pushes its way through the fabric that is clamped over it, and in the second method, a steel ball is pushed through the fabric. These test methods can be applied to all kinds of fabrics such as knitted, felted, woven, nonwoven, and laminated fabrics.
Testing Properties Connected to Aesthetic Appearance and Maintenance:
Properties connected to aesthetic appearance and maintenance of textiles can be examined from, for instance, pilling propensity, wrinkle recovery, dimensional changes in washing, and color fastness to washing, rubbing, and light. Furthermore, appearance of seams can be evaluated after predisposing them to different conditions. Tests that examine such properties give valuable information about how the product would maintain its looks in wear and under textile care operations such as washing and drying.
Pilling:
Surface pilling occurs in almost all fabrics, and it is one of the reasons why a garment is discarded even if it otherwise serves well. Pilling occurs because fibers in yarns and textile structures start to move against each other by wear and abrasion. Fiber ends stick out from the fabric surface and start to curl and tangle around each other causing small balls, pills. It is also common that when fiber ends stick out, they do not entangle and form pills, but lint comes off and fabric loses its thickness. Furthermore, it is usual when rubbing is continued long enough that fibers and pills wear off, and fabric surface appearance may become better looking.
Wrinkle resistance:
Wrinkle resistance is the property that enables a fabric to recover from being folded and from forming undesirable wrinkles. ISO 9867 describes a method for evaluating the appearance of textile fabrics after induced wrinkling. It is applicable to fabrics made from any fiber or combination of fibers.
Color fastness:
Color fastness describes the properties of dyes in fabrics when enduring conditions and chemicals that they are exposed to. ISO 105 is a set of standards that explain test procedures for several color fastness tests, test conditions, and assessing procedures. Generally, one standard explains the determination of color fastness against one factor. Color fastness is assessed in most tests as a change in color and staining. A color fastness test applies not only for the specific dye examined but also for the dyeing procedure. Therefore, the same dye used in a different dyeing procedure might give a different result in a color fastness test. Furthermore, the dyed fiber type has an effect on the result.
In a color fastness test, evaluation is accomplished by assessing the change in color between the original fabric and the specimen after the test. The change in color is evaluated using a gray-assessing scale (ISO 105-A02). The five-step scale contains gray chips next to each other becoming increasingly lighter shades of gray illustrating the perceived color difference in contrasts. In the scale, the rating runs from 5 to 1, where 5 is the best value—no change in color. Staining is evaluated from the standard adjacent fabric that has been attached to the test specimen. Staining is evaluated with the gray–white assessing scale (ISO 105-A03) in which the chips start becoming white and then become increasingly darker gray. In the scale, 5 is the best value and relates to no staining, whereas 1 is the inferior value with the most staining—white–dark gray chips. A multifiber adjacent fabric or two single fiber adjacent fabrics can be used with the specimen.
Color fastness can be assessed against daylight (ISO 105-B01) or artificial light (ISO 105- B02), weathering (ISO 105-B03), domestic and commercial laundering (ISO 105-C06), rubbing (ISO 105-X12), rubbing with organic solvents (ISO 105-D02), sea water and chlorinated swimming pool water (ISO 105-E02 and E03, respectively), and also perspiration (ISO 105- E04) just to give some examples.
Testing Properties Connected to Wear Comfort:
Wear comfort depends on a person’s physical and psychological moods. Physical aspects are connected, for example, to heat equilibrium, whereas psychological aspects are connected to attitude, fashion, and personal situation.
There are textile properties that can be determined through their ability to increase wear comfort. Such properties are, for example, thermal insulation, breathability and air permeability, water absorbency and water removal ability, water repellency and waterproofness, and fabric hand.
Testing Properties Connected to Safety:
One aim of textile testing is to increase the safety of textiles. The aspects connected to safety include, for example, chemicals that cause allergy. Dyes and finishing auxiliaries such as formaldehyde may cause irritation and allergenic reactions. Especially with workwear, the safety aspects are important because the main function of them is to protect the worker from chemicals, flame or heat, metal splashing, radiation, and so on.
Children’s clothing is the kind of textiles that have special criteria for safety. Standard (EN 14682) determines the qualities of cords and drawstrings on children’s clothing. In addition, children’s nightwear should fulfill the burning behavior specification given by the standard (EN 14878).
The flammability of children’s wear and interior textiles such as bed items, curtains, carpets, and upholstered furniture must be tested especially when they are meant for public premises. This is particularly important in fabrics that consist of cotton and other cellulosic fibers though it must be remembered that nettle fiber performs well with regard to flammability.
References:
- Textile and Clothing Design Technology Edited by Tom Cassidy and Parikshit Goswami
- Physical Testing of Textiles by B. P. Saville
- A Practical Guide to Textile Testing By K. Amutha
- https://textilelearner.net/mechanical-properties-of-textile-fibers/
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
