In terms of the life of a textile product, the way of care is as important as the way it is used, because the wear of the textile product occurs as a result of the combined effect of wearing and washing. Recently, the durability of textiles against maintenance operations has become a performance criterion. Care instructions for protecting and prolonging the life of the textile product have gained importance for both the manufacturer and the consumer.
The maintenance process basically consists of washing, drying and ironing steps. Washing takes place mostly in domestic automatic washing machines.The maintenance process includes the stages of soaking the laundry with water, rinsing, removing stains with the help of chemicals (detergent), squeezing the dirty water, rinsing the laundry in clean water (with fabric softener), squeezing as much water as possible, drying the laundry and ironing it if necessary. The steps that harm textiles in many ways are washing in the washing machine and drying in the dryer. In a study, it was found that the main responsible for the wear and tear of textile products over time is the washing process. The physical and chemical effects of the washing process are not very serious under normal conditions, but the cumulative effect resulting from repeated washing processes (average 25-50 washings in the first year) can cause serious damage to some textile products. The following operational parameters of the washing process damage the product by changing some properties of the fibers:
• Water (water/laundry ratio, water level, water hardness)
• Heat
• Mechanical movement
• Washing time (program duration)
• Chemicals (detergent, softener, bleach).
The basic components of textile structures are fiber, yarn, fabric, blanks, dyes and finishes. Every change (damage) that occurs in these components during washing is manifested in the final product.
For this reason, the following factors should be taken into account when evaluating washing performances.:
• Molecular structure and properties
• Fiber structure and properties
• Yarn structure and properties, stresses occurring in the yarn during spinning
• Fabric structure and properties (fabric construction, knitting type, knitting density), stresses in the fabric during weaving/knitting
• Dyeing and finishing
• Care and usage (wearing, washing and drying method, ironing, dry cleaning)
After the washing process in washing machines, various negative effects occur on the fiber and fabric, which are called secondary effects of washing. These effects are listed below considering all fiber types:
1. Swelling of fibers, change in yarn diameters
2. Fiber damage, fiber breakage, fibrillation
3. Tensile and release (dimensional change)
4. Felting
5. May rotation (shape change)
6. Wrinkling, wrinkling
7. Abrasion, change in mass and thickness of the fabric (air permeability, change in water permeability)
8. Change in mechanical properties (tensile, rupture, tear, burst)
9. Pilling
10. Change in surface properties (handle, drape, yarn pulling and pilling)
dimensional change
Maintaining the dimensions of a textile product is a very important factor for consumer use. Shrinkage and/or release in textile products is defined as dimensional change. Dimensional change is one of the first changes observed by the user in the garment after washing in the washing machine.
During washing in the washing machine, dimensional change occurs with the effect of water, temperature and mechanical action. It occurs at different levels depending on the fiber type, yarn structure, fabric construction and finishing type. There are several types of dimensional change, usually manifested in shrinkage.
Relaxation pull:
Relaxation shrinkage is the result of the release of tensile forces applied to the fabric during weaving or knitting. Relaxation shrinkage occurs when the laundry is immersed in water, not during agitation. This shrinkage is especially observed in fibers with good moisture absorption properties. Hydrophilic fibers absorb water and swell. The degree of swelling depends on the fiber, yarn and fabric structure.
The shrinkage problem of the garment occurs in three different stages:
• Fiber stage
• Yarn stage
• Fabric stage
Total shrinkage is the sum of fiber-level shrinkage, yarn-level shrinkage, and fabric-level shrinkage. For example, cotton fabric shrinks by 10%; only 2% of this happens at the fiber and yarn level. In cotton fabrics, shrinkage is mainly seen on a fabric basis. For this reason, cotton fabrics are subjected to a pre-drawing process called sanforizing. In viscose fabrics, shrinkage occurs mainly at the fiber and yarn level. For this reason, the sanforizing process is not effective on viscose fabric.
During the knitting process in knitted fabrics, the loops are stretched longitudinally. During washing, the loops loosen, expand and shorten in length due to the effect of water. During this time, it may take the longest. Fabric content is important. A 100% cotton fabric shrinks more than an elastane-containing cotton fabric.
Progressive pull:
Progressive shrinkage occurs as a result of repeated washings. It is mainly caused by the effect of agitation action. Sufficient agitation in wet condition overcomes the friction between the fibers and provides relative movement. The stronger the shaking motion, the greater the pull. Wool and viscose are more resistant to this type of shrinkage. In a study conducted with rayon fabrics, rayon fabrics washed with a low load shrank more than fabrics washed with a heavy load. The shaking effect is greater when the load is reduced. For this reason, the wash load is important when using standard test methods.
Release:
As a result of washing, an elongation in the dimensions of the textile product can be observed. Generally, as the laundry shrinks in length, the release is more observed in the width of the laundry. It is observed more frequently in knitted fabrics. Stretching the fabric while wet causes release. Lay drying is recommended for fibers with low wet strength and high elongation (such as wool and viscose), as hanging drying promotes release.
Thermal shrinkage:
This is the case for thermoplastic fibers such as acetate, polyester and nylon. With the effect of heat, the fibers take a random, non-linear state and change shape and shrink.
Shape change (may rotation)
The deformation caused by the effect of washing in a textile product is such a serious problem that it affects the use of that product. Shape change is known as may turn in knitted fabrics. It occurs due to the direction of rotation in weft knitted fabrics and as a result of tensions arising from the circular knitting machine. Product groups made of viscose fabrics are prone to may return.
During washing in the washing machine, the tensions loaded on the fabric are released by the effect of water and temperature, the mechanical movement supports the rotation. Shape change in clothing takes place at different levels depending on the fiber type, yarn structure, fabric construction and finishing type.
corrugation
The washing process also affects the appearance properties of textiles in addition to size and shape changes. Textile materials may wrinkle as a result of washing. Wrinkling is the formation of a new balance by sliding the fibers relative to each other under the influence of external force, and the balance being restored when the force is removed. In the washing machine, wrinkling occurs with the effect of water and mechanical action. Crease resistance depends on the fiber type, yarn structure, fabric construction and type of finish.
Cellulosic fibers such as cotton, linen and rayon are known for their low crease resistance. When the fabric is bent, the hydrogen bonds between the cellulose molecules are broken, allowing the relative movement of the molecules. Later, when the ligaments are formed again, the wrinkles are trapped inside the structure. This event can occur in dry and wet state, mostly in wet state. The water used during washing helps to break the hydrogen bonds and when the fabric is dried, the wrinkles remain fixed in the structure.
Because thick yarns are difficult to bend, they show greater resistance to creasing. A viscose fabric made from fine yarn wrinkles more easily than a viscose fabric made from thick yarn. As the twist increases, the tension increases, the yarn structure becomes harder, the recovery ability decreases and the deformation increases. Knitted fabrics wrinkle less than woven fabrics, because the yarns move more easily in the structure and can absorb the stress caused by wrinkling. The tighter the knit, the greater the stretch and the harder it is to smooth out wrinkles. If the structure is loose, there will be less wrinkling. Bursting strength
Strength is the most important tensile property of a textile product that shows its resistance to tensile and tensile forces. During use and washing, textiles are exposed to effects such as stretching, turning, bending, sliding and compression, and their strength decreases.
Bursting strength
It is a size that shows the strength of the fabric against the force applied to the fabric in many directions. Since the yarns do not cut each other in knitted fabrics, burst strength is considered instead of breaking and tearing strengths.
Bursting strength depends on fiber type, yarn type, fabric construction and finish. The strength of viscose fibers is low, the strength decreases even more in wet condition. Yarns made of staple fibers such as viscose are weaker. Fibers can break under mechanical force. The strength of ply yarns is better than single ply yarns. In the yarn with more twist, the friction of the fiber is high, so the strength increases. The larger the yarn count (the thicker the yarn), the greater the strength. In knitted fabrics, the strength is low and the elongation is high.
pilling
Pilling is a surface defect in the form of small beads formed by entangling and curling fibers and clinging to the fabric surface. It occurs due to the friction effect that occurs as a result of mechanical action during washing in the washing machine. Low water level, long wash cycle, excess laundry, repeated washings contribute to pilling.
Pilling depends on fiber type, yarn type, fabric construction and finish. Fabric structures consisting of staple fiber pills considerably. When the fabric is abraded, the staple fibers weaken and rise to the surface of the fabric. Fabric structures consisting of a single fiber have less pilling than fabrics consisting of mixed fibers. Pilling can be reduced by using thicker, stiffer, twisted yarns. Tough yarns are resistant to bending and bending, no tangles. Knitted fabrics pill more than woven fabrics.
Wear
Thinning, tearing or perforation of a textile product by the effect of washing in the washing machine are indicators of wear. Wear is closely related to friction caused by mechanical action. The following changes can be observed in the textile structure with the effect of friction and wear on the fabric:
• Weight loss
• Thread breakage
• Increase in air and water permeability
• Felting of wool
• Pilling, formation of lumps
Fabric wear can be of four types:
• The fabric may rub against the fabric (laundry). It occurs as a result of repeated washings and reaches a noticeable level.
• The fabric may rub against another object (washing drum). During washing, textile products are abraded by rubbing against the drum.
• As the fabric stretches and bends, the fibers and yarns in the structure may rub against each other. When woven or knitted fabrics are stretched and bent, the fibers and threads slide over each other. If a fabric is repeatedly stretched/bent, tensile and compressive forces are applied one after the other, causing the fibers and yarns to slide and rub back and forth. Abrasion occurs as a result of rubbing, which may result in tearing.
• Foreign substances such as dust, sand, residue (detergent) may hold in the fabric and rub against the fibers that make up the structure. When the fabric is bent and stretched, it can easily abrade the fibers and threads in the fabric.
The abrasion resistance of cellulosic fibers is quite low. Since the surface is rough, the friction coefficient and wear tendency are high. The thicker the yarn, the greater the resistance to abrasion forces. As the twist increases, the yarn diameter decreases and a tighter structure is formed, and the abrasion resistance increases. The higher the fabric density, the higher the abrasion resistance. Against the wear force, more yarn absorbs energy, so the amount of tension falling on a single yarn is reduced. Knitted fabrics are more resistant to abrasion than woven fabrics. Moisture can increase or decrease wear resistance. Fabrics made from fibers that are stronger when wet are more resistant to abrasion when wet. Fibers that are unstable in the wet state can easily wear out when wet.
Change in surface properties – Handle and drape
In addition to the negative effects listed above, the surface and aesthetic properties of the fabric also change with the effect of washing. Two aesthetic properties of fabrics are mentioned. These are the touch and drape of the fabric.
Handle is the feeling that the fabric gives to the person holding it when held by hand. Various adjectives have been defined for the levels of this feeling: These are smooth (smooth), rough, hard, soft, etc. For example, when wool is rough, pure silk feels rusty. The structural properties of fabrics affect their physical and mechanical properties, which in turn affects the touch.
Fine and filament yarns create smooth surfaces, whereas thick and staple yarns make the surface rough.
Fine fibers increase the flexibility of yarns and fabrics.
Microfibers soften the touch of the fabric.
Thick yarn, low yarn curl, thick fabric and increased density increase bending resistance. Fabric touch finishing treatments can be modified with softeners and coatings.
While starches make the fabric hard and less flexible, fabric softeners soften it.
drape, The fabric is shedding with its own weight and forming folds. Draping is related to bending, shear forces and fabric weight. If the bending resistance is low, the drape will be high. The shear force occurs as a result of the movement of the yarns in the fabric relative to each other. Flexible, smooth surfaced yarns glide more easily. In knitted fabrics, the looped structure allows the yarns to rotate and accommodates the shear force. Knitted fabrics show better draping properties than woven fabrics. Loose textured structures also support draping.
Chemical effects - Detergent effect
Since detergents are basic, fibers that are unstable to bases are adversely affected by the detergent. In particular, the bleaching agents and catalysts in the detergent cause chemical damage to textiles. With the bleaching effect, macromolecules are broken down and the degree of polymerization decreases. The tensile strength of fibers, yarns and fabrics deteriorates.
Cellulosic fibers are resistant to alkaline detergents. Anti-shrinkage and anti-wrinkle finishes applied to the cellulosic fiber are easily affected by repeated washings with detergents and are hydrolyzed slowly. As the washing becomes more frequent, the performance and appearance of the fabric deteriorates as the function of the finishes will decrease.
Studies in the literature on washing effects and their results
There are various studies in the literature on the effects of household washing on textile products. Studies were generally carried out on plain woven fabrics with 100% cotton content, single jersey and 100x1 rib knitted fabrics with 1% cotton content. In addition, there are studies examining the effects of washing on knitted fabrics such as wool, silk, polyester, acrylic and cotton/polyester blend twill, satin weave and interlock, lacoste, three-yarn, pique. In order to diversify the material, different fiber blends, different yarn counts, yarns produced with different yarn spinning systems, different knitting types and knitting densities, and samples with different finishes were used.
The most studied washing effects on fabrics made from various fibers are dimensional change and may turn. Along with these effects, felting, abrasion, pilling and changes in mechanical, surface and sensory properties affecting the comfort of the textile product and loss of finishing were investigated.
In the studies on the washing effect, ISO (BS EN), AATCC, ASTM standards that are valid all over the world, easily accessible, reliable and practical have been used. There are also studies in the literature examining the interaction of the parameters of the washing process and textile products. Among these parameters, there are variables such as washing method (washing with or without detergent), washing temperature, mechanical action, drying method (drying or hanging/laying) and softener usage.
1. Washing has a cumulative effect on the laundry.
2. Since hydrophilic fibers absorb more water and swell, natural fibers have more shrinkage and rotational effects. Since cotton is highly resistant to high temperatures, the washing temperature is high. Since wool fiber is sensitive and prone to felting due to its special scaly structure, it is necessary to wash it delicately and use special detergents. Synthetic fibers are more affected by temperature.
3.Repeated washings lead to peeling of the surface layer of the fibers and the formation of spiral cracks parallel to the fiber length.
4. The visible effect of washing is mostly seen on knitted fabrics (especially single jersey and rib fabric). The effect is less on woven fabrics. (maximum effect in satin weave)
5. The washing process shows its effect after five washings on knitted fabrics and after ten washings on woven fabrics.
6. In a study with knitted fabrics, the effect of loop structure, knitting density, yarn type and fiber content on shrinkage was investigated. The loops loosen with the effect of washing. According to the knitting type, the longitudinal shrinkage is more or less than the transverse shrinkage. As the fabric becomes denser, the transverse shrinkage increases during washing. For longitudinal pulling, the situation is the opposite. Cotton / polyester blended fabrics shrank less than 100% cotton fabric. The influence of the yarn type is not as dominant as the fiber content.
7. Loop yarn length is an important parameter for the washing behavior of knitted fabrics. Weight, burst strength, fabric thickness, pilling and abrasion resistance were investigated on fabrics with different loop yarn lengths (knit density). As the fabric becomes denser, the number of rows/cm and the transverse shrinkage increase, while the longitudinal shrinkage decreases.
8. Protective and functional finishes on textile products reduce the washing effect. However, repeated washings cause the finish to come off, thus reducing the effect time.
9. The effect of using detergent during the washing process is not much. It has been observed that the detergent effect on finished fabrics is slightly higher as it causes a loss of finish.
10. The use of fabric softener during washing has a positive effect on shrinkage and wrinkling effects.
11. In a research conducted to find out which step of washing/drying is the cause of the shrinkage and mash rotation rates in fabrics, the washing and drying steps are isolated; The steps were determined as washing, rinsing, spinning, rinsing during drying and dryer temperature. According to the study, the main variable that causes a negative effect on textiles is mechanical movement. The rates of effect of washing and drying steps on shrinkage and may rotation are included. The spin step, in which the mechanical movement and agitation are most intense, is the most important cause of the effect on textiles. If we include the drying process in the cycle, the shaking movement during drying in the dryer causes the greatest damage (34%) to the textiles.
12. Damage to textile fibers is mostly caused by the combined effect of mechanical action and chemicals (bleach).
13. The highest shrinkage value is reached after the first wash. The effect continues to decrease in continued washings.
14. Drying in the dryer increases the shrinkage level compared to drying by laying, while reducing the level of wrinkles. However, it causes more damage to the fibers thanks to the shaking action.
