Fundamental processes involved in the manufacturing of textiles
The word ‘textile’ in the most literal sense means “to weave” and has originated from the Latin word textilis and the French word texere. The word is often used to define woven fabric. Textiles thereby forming the foundation of garments.
Over the years the term has been associated with the following:
• Staple or filament fibers spun to form yarns or manufacturing of woven, knitted, non-woven, or tufted fabrics.
• Yarns derived from cellulosic or plant fibers.
• Fabrics and other products made by the interlacement of yarns or its constituent fibers.
• Apparel or other articles derived from the above processes which possess both functional and desired properties as per the requirement of that particular garment.
These broad definitions cover all of the products produced by the textile industry intended for intermediate structures or final products. When we look at the various kinds of materials used for cutlery or kitchenware, we find that an earthen pot is very different from glassware. What makes the two different is that the raw material used i.e. mud and glass respectively. Similarly, the properties of each textile material are different because of the unique chemical building blocks or monomers they constitute.
The textile manufacturing process involves the following steps:
1. Fiber Formation: Textile fibers, like most substances, are made of molecules. Each individual fiber is made up of millions of individual long molecular chains of discrete chemical structure. The arrangement and orientation of these molecules within the individual fiber, along with the cross-section and shape of the fiber (morphology), will affect fiber properties. The fiber molecules are referred to as polymers.
The fibers are either obtained from nature in the fibrous form via the plant and animal sources, or regenerated by taking raw material from nature and further dissolved through a series of chemical reactions or are commercially produced in the industry from chemicals to form polymers. The fibers thus obtained may be short in length called staple fibers or continuous and long length referred to as filament fibers.
2. Yarn Formation: Textile yarns are continuous strands made up of textile fibers, the basic physical structures or elements which make up textile products. Yarn is an assembly of fibers having substantial length and cross-section, with or without twists.
Yarns are basically classified into 3 types: Spun Yarns made from staple fibers which form the first classification. Natural fibers such as cotton, linen, and jute are short in length and therefore are required to be twisted tightly for them to hold together. These yarns generally require mechanical spinning and possess a dull, fuzzy look.
The next category is the filament yarns made by chemical spinning such as melt, wet or dry spinning. All synthetic fibers are produced as filament yarns. These may be monofilament i.e. made by a single filament or multifilament i.e. made from a large number of filaments held together with or without twists. Monofilament yarns are stiffer and coarser while multifilament yarns are soft and pliable.
The formation of yarns is achieved by the method of spinning fibers. It is the process of drawing out and twisting fibers to consolidate them to form a continuous thread or yarn.
The conventional spinning system used for spun yarns involves the following operations: 1. Opening, cleaning, and blending (loosening and detangling of yarn package along with fiber uniformity) 2. Carding (alignment and removal of short fibers) 3. Combing (to obtain smooth, even and strong fibers, optional step) 4. Drawing and drafting (combining of fibers to eliminate irregularities) 5. Roving (imparts twist).
Some other non-conventional spinning methods include: rotor or open-end spinning, water jet spinning, air-jet spinning, friction spinning, self-twist spinning, electro-static spinning, etc. Filament spinning systems are much less complex because the fibers are continuous and do not need to be highly twisted to give a cohesive strong yarn. These methods include melt, dry, wet, emulsion, and gel spinning processes.
3. Fabric Production:
After the yarn formation, the next step involves the conversion of yarns into a fabric that possesses the desired properties. The fabric obtained from yarns or fiber webs is a product of either of the following techniques such as weaving, knitting, tufting, and nonwoven formation, braiding or plaiting. However, the most widely used method is weaving. Weaving is a process of laying the warp and weft yarns to make a woven structure. A conventional woven fabric is a textile structure formed on a loom when two sets of yarns are interlaced at right angles. The longitudinal yarns are called the warp and widthwise yarns are referred to as weft or filling.
The design produced as a result of this interlacement of yarns is referred to as a weave and so various weaves such as plain weave, rib, twill, satin along with fancy weaves such as dobby, pile, jacquard, leno, and gauze can be produced by altering various factors such as the number of harness in a loom, threading pattern of warps, through healds, lifting plan of harness etc.
Another method that is catching up fast is knitting. Knitting is a process of forming interlocking loops, made of one or more yarns. As new loops are formed, they are drawn through the previous ones, thus producing a knitted fabric. A loop or a stitch is the basic structural element of knit construction. The vertical column of loops that run parallel to the lengthwise direction of knitted fabric is called wale and the horizontal rows running crosswise are called course.
Apart from employing the technique of weaving and knitting, there is another fabric construction technique known as non-woven fabric. The process of non-woven fabric construction eliminates conventional textiles processes. Non-woven are broadly classified into two groups i.e. felts and bonded fabrics. Felts are fabric structures made by interlocking the scales of wool fibers or achieved by fiber entanglement via the action of needles. The felts are further classified into wool felts and needle felts. Bonded fabrics, on the other hand, are flexible materials that are formed directly from the fibers and rely on thermal or chemical treatment for their construction. Bonded fabrics are classified on the method of bonding employed such as adhesive bonding, spun bonded, melt blown, thermal bonding, etc.
The basic steps in non-woven construction are:1. Preparation of fibers (opening, cleaning, and blending) 2. Formation of web 3. Bonding (Mechanical: needle punching, felt; Heat and pressure; Adhesive used; Melt blowing) 4. Finishing (Dyeing and printing).
Lastly, the fabric is treated with certain finishing treatments to impart both functional and desired properties along with dyeing and printing processes.
4. Garment Construction:
After the fabric is constructed, it is then sewn into apparel and other articles. The textiles are broadly categorized into the three divisions namely: apparel, home, and industrial textiles.