The Textile Industry
The term textile industry (from the Latin texere, to weave) was originally applied to the weaving of fabrics from fibres, but now it includes a broad range of other processes such as knitting, tufting, felting and so on. It has also been extended to include the making of yarn from natural or synthetic fibres as well as the finishing and dyeing of fabrics.
In prehistoric eras, animal hair, plants and seeds were used to make fibres. Silk was introduced in China around 2600 BC, and in the middle of the 18th century AD, the first synthetic fibres were created. While synthetic fibres made from cellulose or petrochemicals, either alone or in varied combinations with other synthetic and/or natural fibres, have seen increasingly widening use, they have not been able to totally eclipse fabrics made of natural fibres such as wool, cotton, flax and silk.
Silk is the only natural fibre formed in filaments which can be twisted together to make yarn. The other natural fibres must first be straightened, made parallel by combing and then drawn into a continuous yarn by spinning. The spindle is the earliest spinning tool; it was first mechanized in Europe around 1400 AD by the invention of the spinning wheel. The late 17th century saw the invention of the spinning jenny, which could operate a number of spindles simultaneously. Then, thanks to Richard Arkwright’s invention of the spinning frame in 1769 and Samuel Crompton’s introduction of the mule, which allowed one worker to operate 1,000 spindles at one time, yarn-making moved from being a cottage industry into the mills.
Making of fabric
The making of fabric had a similar history. Ever since its origins in antiquity, the hand loom has been the basic weaving machine. Mechanical improvements began in ancient times with the development of the heddle, to which alternate warp threads are tied; in the 13th century AD, the foot treadle, which could operate several sets of heddles, was introduced. With the addition of the frame-mounted batten, which beats the weft or filling yarns into place, the “mechanized” loom became the predominant weaving instrument in Europe and, except for traditional cultures where the original hand looms persisted, around the world.
John Kay’s invention of the flying shuttle in 1733, which allowed the weaver to send the shuttle across the width of the loom automatically, was the first step in mechanization of weaving. Edmund Cartwright developed the steam-powered loom and in 1788, with James Watt, built the first steam-driven textile mill in England. This freed the mills from their dependence on water-driven machinery and allowed them to be constructed anywhere. Another significant development was the punch-card system, developed in France in 1801 by Joseph Marie Jacquard; this allowed automated weaving of patterns. The earlier power looms made of wood were gradually replaced by looms made of steel and other metals. Since then, technological changes have focused on making them larger, faster and more highly automated.
Dyeing and printing
Natural dyes were originally used to impart colour to yarns and fabrics, but with the 19th-century discovery of coal-tar dyes and the 20th-century development of synthetic fibres, dyeing processes have become more complicated. Block printing was originally used to colour fabrics (silk-screen printing of fabrics was developed in the mid-1800s), but it soon was replaced by roller printing. Engraved copper rollers were first used in England in 1785, followed by rapid improvements that allowed roller printing in six colours all in perfect register. Modern roller printing can produce over 180 m of fabric printed in 16 or more colours in 1 minute.
Early on, fabrics were finished by brushing or shearing the nap of the fabric, filling or sizing the cloth, or passing it through calender rolls to produce a glazed effect. Today, fabrics are pre-shrunk, mercerized (cotton yarns and fabrics are treated with caustic solutions to improve their strength and lustre) and treated by a variety of finishing processes that, for example, increase crease resistance, crease holding and resistance to water, flame and mildew.
Special treatments produce high-performance fibres, so called because of their extraordinary strength and extremely high temperature resistance. Thus, Aramid, a fibre similar to nylon, is stronger than steel, and Kevlar, a fibre made from Aramid, is used to make bullet-proof fabrics and clothing that is resistant both to heat and chemicals. Other synthetic fibres combined with carbon, boron, silicon, aluminium and other materials are used to produce the lightweight, superstrong structural materials used in airplanes, spacecraft, chemical resistant filters and membranes, and protective sports gear.
From hand craft to industry
Textile manufacture was originally a hand craft practised by cottage spinners and weavers and small groups of skilled artisans. With the technological developments, large and economically important textile enterprises emerged, primarily in the United Kingdom and the Western European countries. Early settlers in North America brought cloth mills to New England (Samuel Slater, who had been a mill supervisor in England, constructed from memory a spinning frame in Providence, Rhode Island, in 1790), and the invention of Eli Whitney’s cotton gin, which could clean harvested cotton with great speed, created a new demand for cotton fabrics.
This was accelerated by the commercialization of the sewing machine. In the early 18th century, a number of inventors produced machines that would stitch cloth. In France in 1830, Barthelemy Thimonnier received a patent for his sewing machine; in 1841, when 80 of his machines were busy sewing uniforms for the French army, his factory was destroyed by tailors who saw his machines as a threat to their livelihood. At about that time in England, Walter Hunt devised an improved machine but abandoned the project because he felt that it would throw poor seamstresses out of work. In 1848, Elias Howe received a US patent for a machine much like Hunt’s, but became embroiled in legal battles, which he ultimately won, charging many manufacturers with infringement of his patent. The invention of the modern sewing machine is credited to Isaac Merritt Singer, who devised the overhanging arm, the presser foot to hold down the cloth, a wheel to feed the fabric to the needle and a foot treadle instead of a hand crank, leaving both hands free to manoeuvre the fabric. In addition to designing and manufacturing the machine, he created the first large-scale consumer-appliance enterprise, which featured such innovations as an advertising campaign, selling the machines on the installment plan, and providing a service contract.
Thus, the technological advances during the 18th century were not only the impetus for the modern textile industry but they can be credited with the creation of the factory system and the profound changes in family and community life that have been labelled the Industrial Revolution. The changes continue today as large textile establishments move from the old industrialized areas to new regions that promise cheaper labour and sources of energy, while competition fosters continuing technological developments such as computer-controlled automation to reduce labour needs and improve quality. Meanwhile, politicians debate quotas, tariffs and other economic barriers to provide and/or retain competitive advantages for their countries. Thus, the textile industry not only provides products essential for the world’s growing population; it also has a profound influence on international trade and the economies of nations.
Safety and Health Concerns
As machines became larger, speedier and more complicated, they also introduced new potential hazards. As materials and processes became more complex, they infused the workplace with potential health hazards. And as workers had to cope with mechanization and the demand for increasing productivity, work stress, largely unrecognized or ignored, exerted an increasing influence on their well-being. Perhaps the greatest effect of the Industrial Revolution was on community life, as workers moved from the country to cities, where they had to contend with all of the ills of urbanization. These effects are being seen today as the textile and other industries move to developing countries and regions, except that the changes are more rapid.
The hazards encountered in different segments of the industry are summarized in the other articles in this chapter. They emphasize the importance of good housekeeping and proper maintenance of machines and equipment, the installation of effective guards and fences to prevent contact with moving parts, the use of local exhaust ventilation (LEV) as a supplement to good general ventilation and temperature control, and the provision of appropriate personal protective equipment (PPE) and clothing whenever a hazard cannot be completely controlled or prevented by design engineering and/or substitution of less hazardous materials. Repeated education and training of workers on all levels and effective supervision are recurrent themes.
Environmental concerns raised by the textile industry stem from two sources: the processes involved in textile manufacture and hazards associated with the way the products are used.
The chief environmental problems created by textile manufacturing plants are toxic substances released into the atmosphere and into wastewater. In addition to potentially toxic agents, unpleasant odours are often a problem, especially where dyeing and printing plants are located near residential areas. Ventilation exhausts may contain vapours of solvents, formaldehyde, hydrocarbons, hydrogen sulphide and metallic compounds. Solvents may sometimes be captured and distilled for reuse. Particulates may be removed by filtration. Scrubbing is effective for water-soluble volatile compounds such as methanol, but it does not work in pigment printing, where hydrocarbons make up most of the emissions. Flammables may be burned off, although this is relatively expensive. The ultimate solution, however, is the use of materials that are as close to being emission-free as possible. This refers not only to the dyes, binders and cross-linking agents used in the printing, but also to the formaldehyde and residual monomer content of fabrics.
Contamination of wastewater by unfixed dyes is a serious environmental problem not only because of the potential health hazards to human and animal life, but also because of the discolouration that makes it highly visible. In ordinary dyeing, fixation of over 90% of the dyestuff can be achieved, but fixation levels of only 60% or less are common in printing with reactive dyes. This means that more than one-third of the reactive dye enters the wastewater during the washing-off of the printed fabric. Additional amounts of dyes are introduced into the wastewater during the washing of screens, printing blankets and drums.
Limits on wastewater discolouration have been set in a number of countries, but it is often very difficult to heed them without an expensive wastewater purification system. A solution is found in the use of dyestuffs with a lesser contaminating effect and the development of dyes and synthetic thickening agents that increase the degree of dye fixation, thereby reducing the amounts of the excess to be washed away (Grund 1995).
Environmental concerns in textile use
Residues of formaldehyde and some heavy-metal complexes (most of these are inert) may be sufficient to cause skin irritation and sensitization in persons wearing the dyed fabrics.
Formaldehyde and residual solvents in carpets and fabrics used for upholstery and curtains will continue to vaporize gradually for some time. In buildings that are sealed, where the air-conditioning system recirculates most of the air rather than exhausting it to the outside environment, these substances may reach levels high enough to produce symptoms in the occupants of the building, as discussed elsewhere in this Encyclopaedia.
To ensure the safety of fabrics, Marks and Spencer, the British/Canadian clothing retailer, led the way by setting limits for formaldehyde in garments they would purchase. Since then, other garment manufacturers, notably Levi Strauss in the United States, have followed suit. In a number of countries, these limits have been formalized in laws (e.g., Denmark, Finland, Germany and Japan), and, in response to consumer education, fabric manufacturers have been voluntarily adhering to such limits in order to be able to use eco labels (see figure 1).
Figure 1. Ecological labels used for textiles
Technological developments are continuing to enhance the range of fabrics produced by the textile industry and to increase its productivity. It is most important, however, that these developments be guided also by the imperative of enhancing the health, safety and well-being of the workers. But even then, there is the problem of implementing these developments in older enterprises that are marginally financially viable and unable to make the necessary investments, as well as in developing areas eager to have new industries even at the expense of the health and safety of the workers. Even under these circumstances, however, much can be achieved by education and training of the workers to minimize the risks to which they may be exposed.