Silk dresses
'Silk' is a natural
protein fiber, some forms of which can be
woven into
textiles. The best-known type of silk is obtained from
cocoons made by the
larvae of the
silkworm ''
Bombyx mori'' reared in captivity (
sericulture). The shimmering appearance for which silk is prized comes from the fibers' triangular
prism-like structure which allows silk cloth to refract incoming light at different angles.
"Wild silks" or 'tussah silks' (also spelled "tasar") are produced by caterpillars other than the
mulberry silkworm (''
Bombyx mori''). They are called "wild" as the silkworms cannot be artificially cultivated like ''Bombyx mori''. A variety of wild silks have been known and used in
China,
India, and
Europe from early times, although the scale of production has always been far smaller than that of cultivated silks. Aside from differences in colors and textures, they all differ in one major aspect from the domesticated varieties: the cocoons that are gathered in the wild have usually already been damaged by the emerging moth before the cocoons are gathered, and thus the single thread that makes up the cocoon has been torn into shorter lengths. Commercially reared silkworm pupae are killed before the adult moths emerge by dipping them in boiling water or piercing them with a needle, thus allowing the whole cocoon to be unraveled as one continuous thread. This allows a much stronger cloth to be woven from the silk. Wild silks also tend to be more difficult to dye than silk from the cultivated silkworm.
There is some evidence that small quantities of wild silk were already being produced in the Mediterranean area and the Middle East by the time the superior, and stronger, cultivated silk from China began to be imported .
Silks are produced by several other insects, but only the silk of moth caterpillars has been used for textile manufacture. There has been some research into other silks, which have differences at the molecular level. Silks are mainly produced by the
larvae of insects with
complete metamorphosis, but also by some adult insects such as
webspinners. Silk production is especially common in the
Hymenoptera (
bees,
wasps, and
ants), and is sometimes used in nest construction. Other types of
arthropod produce silk, most notably various
arachnids such as
spiders (see
spider silk).
History of silk
Main articles: History of silk
China
''Landscape of quick water from high mountain'' by Zhao Zuo, 1611 AD,
Ming Dynasty. Hand scroll, ink and colour on silk.
Silk fabric was first developed in ancient
China, possibly as early as
6000 BC and definitely by
3000 BC. Legend gives credit to a Chinese empress,
Xi Ling-Shi (Hsi-Ling-Shih, Lei-Tus). Silks were originally reserved for the kings of China for their own use and gifts to others, but spread gradually through
Chinese culture both geographically and socially, and then to many regions of
Asia. Silk rapidly became a popular luxury fabric in the many areas accessible to Chinese merchants because of its texture and luster. Silk was in great demand, and became a staple of pre-
industrial international
trade. In July of 2007, archeologists have discovered intricately weaved and dyed silk
textiles in a tomb of
Jiangxi province that are dated to the Eastern
Zhou Dynasty, roughly 2,500 years ago.
[1] Although historians have suspected a long history of a formative textile industry in ancient China, this find of silk textiles employing "complicated techniques" of weaving and dyeing provides direct and concrete evidence for silks dating before the
Mawangdui-discovery and other silks dating to the
Han Dynasty (202 BC–220 CE).
The first evidence of the silk trade is the finding of silk in the hair of an
Egyptian
mummy of the 21st dynasty, c.
1070 BCE [1]. Ultimately the silk trade reached as far as the
Indian subcontinent, the
Middle East,
Europe, and
North Africa. This trade was so extensive that the major set of trade routes between Europe and Asia has become known as the
Silk Road.
The
Emperors of China strove to keep knowledge of sericulture secret to maintain the Chinese
monopoly. Nonetheless sericulture reached
Korea around
200 BC, about the first half of the
1st century CE had reached ancient
Khotan [2], and by CE
300 the practice had been established in India.
Thailand
Silk is produced in
Thailand's favorable climate by two types of silkworms, the cultured Bombycidae and wild Saturniidae, all the year round, mostly after the rice harvest by villagers from the central and northeast parts of the country. Women traditionally weave silk on hand looms, and pass the skill on to their daughters as weaving is considered to be a sign of maturity and eligibility for marriage. Thai silk textiles often use complicated patterns in various colors and styles. Most regions of Thailand have their own typical silks, of which Mud-Mee, Tin Chok and Phrae Wa are among the best.
India and Nepal
Silk, known as ''Pattu'' or ''Reshmi'' in southern parts of
India and ''Resham'' in Hindi, has a long history in India and is widely produced today. Historically silk was used by the upper classes, while cotton was used by the poorer classes. Today silk is mainly used in
Bhoodhan Pochampally (also known as
Silk City),
Kanchipuram, Dharmavaram, Mysore, etc. in South India and
Banaras in the North for manufacturing
garments and
Sarees. "Murshidabad silk", famous from historical times, is mainly produced in Malda and Murshidabad district of West Bengal and woven with hand looms in Birbhum and Murshidabad district. Another place famous for production of silk is
Bhagalpur. The silk from Kanchi is particularly well-known for its classic designs and enduring quality. The silk is traditionally hand-woven and hand-dyed and usually also has silver threads woven into the cloth. Most of this silk is used to make saris. The saris usually are very expensive and vibrant in color. Garments made from silk form an integral part of Indian weddings and other celebrations. In the northeastern state of
Assam, three different types of silk are produced, collectively called
Assam silk: Muga, Eri and Pat silk. Muga, the golden silk, and Eri are produced by silkworms that are native only to Assam. The heritage of silk rearing and weaving is very old and continues today especially with the production of Muga and Pat ''riha'' and ''
mekhela chador'', the three-piece silk
saris woven with traditional motifs. ''Mysore Silk Sarees'', which are known for their soft texture and expensive class last easily as long as 25 to 30 years, if maintained well.
Mediterranean world
In the
Odyssey, 19.233, it is mentioned that Odysseus wore a shirt "gleaming like the skin of an onion" (varies with translations, literal translation requested). Some researchers proposed that the shirt was made of silk.
The
Roman Empire knew of and traded in silk. During the reign of emperor
Tiberius,
sumptuary laws were passed that tried to forbid men from wearing silk garments but these proved ineffectual.
[3] Despite the popularity of silk, the secret of silk-making was only to reach Europe around CE
550, via the
Byzantine Empire. Legend has it that monks working for the emperor
Justinian smuggled silkworm eggs to
Constantinople in hollow canes. The
Byzantines were as secretive as the Chinese, and for many centuries the weaving and trading of silk fabric was a strict imperial monopoly; all top-quality looms and weavers were located inside the Palace complex in
Constantinople and the cloth produced was used in imperial robes or in diplomacy, as gifts to foreign dignitaries. The remainder was sold at very high prices.
Islamic world
In
Islamic teachings, Muslim men are forbidden to wear silk. Many religious jurists believe the reasoning behind the prohibition lies in avoiding clothing for men that can be considered feminine or extravagant and luxurious.
[4] Despite injunctions against silk for men, silk has retained its popularity in the Islamic world because of its permissibility for women. The Muslim
Moors brought silk with them to Spain during their conquest of the Iberian Peninsula.
Medieval and modern Europe
Venetian merchants traded extensively in silk and encouraged silk growers to settle in
Italy. By the 13th century, Italian silk was a significant source of trade. Since that period, the silk worked in the
province of Como has been the most valuable silk in the world. The wealth of
Florence was largely built on textiles, both
wool and silk, and other cities like
Lucca also grew rich on the trade. Italian silk was so popular in Europe that
Francis I of France invited Italian silk makers to France to create a French silk industry, especially in
Lyon. Mass emigration (especially of
Huguenots) during periods of religious dispute had seriously damaged French industry and introduced these various textile industries, including silk, to other countries.
James I attempted to establish silk production in England, purchasing and planting 100,000 mulberry trees, some on land adjacent to
Hampton Court Palace, but they were of a species unsuited to the silk worms and the attempt failed. Production started elsewhere later. In
Italy, the
Stazione Bacologica Sperimentale was founded in
Padua in 1871 to research sericulture. In the late
19th century, China, Japan, and Italy were the major producers of silk. The most important cities for silk production in Italy were
Como and
Meldola (
Forlì).
Silk was expensive in Medieval Europe and used only by the rich. Italian merchants like
Giovanni Arnolfini became hugely wealthy trading it to the Courts of Northern Europe.
North America
James I of England introduced silk-growing to the American colonies around 1619, ostensibly to discourage
tobacco planting. Only the
Shakers in Kentucky adopted the practice. In the
1800s a new attempt at a silk industry began with European-born workers in
Paterson, New Jersey, and the city became a US silk center, although Japanese imports were still more important.
World War II interrupted the silk trade from
Japan. Silk prices increased dramatically, and US industry began to look for substitutes, which led to the use of
synthetics such as
nylon. Synthetic silks have also been made from
lyocell, a type of
cellulose fiber, and are often difficult to distinguish from real silk (see
spider silk for more on synthetic silks).
Major Fiber Properties
Physical Properties
Shape
Silk has a triangular shaped cross section whose corners are rounded.
Luster
Due to the triangular shape (allowing light to hit it at many different angles), silk is a bright fiber meaning it has a natural shine to it
Covering Power
Silk fibers have poor covering power. This is caused by their thin filament form.
Hand
When held silk has a smooth, soft texture that, unlike many synthetic fibers, is not slippery
Denier
4.5 g/d (dry) ; 2.8-4.0 g/d (wet)
Mechanical Properties
Strength
Silk is the strongest of all the natural fibers; however it does lose up to 20% of its strength when wet.
Elongation/Elasticity
Silk has moderate to poor elasticity. If elongated even a small amount the fibers will remain stretched.
Resiliency
Silk has moderate wrinkle resistance
Chemical Properties
Absorbency
Silk has a good moisture regain of 11%. The gaining value of this is too add another 11% to it.
Electrical Conductivity
Silk is a poor conductor of electricity making it comfortable to wear in cool weather. This also means however, that silk is susceptible to static cling.
Resistance to Ultraviolet Light/ Biological Organisms
Silk can become weakened if exposed to too much sunlight. Silk may also be attacked by insects, especially if left dirty.
Chemical Reactivity/Resistance
Silk is resistant to mineral acids. It is yellowed by perspiration and will dissolve in sulphuric acid.
Other Properties
Dimensional Stability
Silk does not generally shrink due to the fact that its molecular structure is not easily distorted.
Uses for Silk
Apparel
Silk is excellent for use in warm weather and active clothing. The silk's good absorbency makes it comfortable to wear in such conditions. Silk is also excellent in the cold because its low conductivity keeps the wearer warm.
Examples of Silk Clothing
★ Underwear
★ Socks
★ Leggings
★ T-shirts
★ High fashion and discount clothing
★ Tops
★ Pajamas
Furnishings
Silk's elegant, soft luster and beautiful drape makes it perfect for many furnishing applications.
Examples of Silk Furnishings:
★ Upholstery
★ Wall Coverings
★ Window Treatments (if blended with another fiber)
★ Rugs
★ Bedding
★ Wall Hangings
Animal rights
As the process of harvesting the silk from the cocoon kills the larvae, silk-culture has been criticized in the early 21st century by
animal rights activists on the grounds that silk production kills silkworms, and that artificial silks are available.
[5] Others point out that silkworms depend upon humans for their survival, and would become extinct without humans to care for the worms and harvest the silk.
[6]
Mahatma Gandhi was critical of silk production based on the
Ahimsa philosophy. Ahimsa is part of the three millennial Jain philosophy of India "not to hurt any living thing," which led to development of a cotton spinning machine he distributed. Such a machine can be seen in the Gandhi Institute.
''Ahimsa Silk'', made from the cocoons of wild and semi-wild silk moths, is being promoted in parts of Southern India, for those who prefer not to wear silk produced which involves the death of silkworms.
Other uses
Mongols used silk as part of the under-armor garments (see
Mongolian armor). Silk is so tough that it was actually used as very light armor, although its special use was to stop arrow penetration into the body. The silk would stop an arrow from penetrating far enough into the body to be lethal, and the arrow could be pulled out of the wound by tugging on the unbroken silk. The head of an arrow pulled out this way would not contact the body, reducing the likelihood of infection.
In addition to clothing manufacture and other handicrafts, silk is also used for items like
parachutes, bicycle
tires,
comforter filling and
artillery gunpowder bags. Early
bulletproof vests were also made from silk in the era of
blackpowder weapons until roughly
World War I. Silk undergoes a special manufacturing process to make it suitable for use as non-absorbable surgical
sutures. Chinese doctors have also used it to make prosthetic arteries. Silk cloth is also used as a material to write on.
Production Methods
'Sericulture:' the production of cultivated silk
# Silk moths lay eggs on specially prepared paper.
# Eggs hatch and the caterpillars are fed fresh mulberry leaves.
# After about 35 days, and 4 moltings, the silkworms are 10,000 times heavier than when hatched – they are now ready to begin spinning a cocoon.
# A straw frame is placed over tray of silkworms – they begin spinning cocoons by moving their heads in a figure 8.
# Liquid silk, coated in sericin, is produced in 2 of the silkworm’s glands, which is forced through spinnerets.
#
★ 'Sericin:' water-soluble protective gum
#
★ 'Spinnerets:' openings in silkworm’s head
# As this liquid silk comes into contact with the air, it solidifies.
# Within 2-3 days, the silkworm will have spun 1 mile of filament and will be completely encased in a cocoon.
# After this entire process, the silkworm metamorphoses into a moth, but is usually killed by heat before it reaches the moth stage – any silkworm reaching the moth stage is used for breeding the next generation of silkworms.
'To obtain filament silk:'
# Cocoons that have been stifled are sorted by fiber size, fiber quality, and defects, then are brushed to find filaments.
# Several filaments are gathered together and wound onto a wheel ('reeling').
# Each cocoon yields 1000 yards of silk filament, known as raw silk, or silk-in-the gum, fiber.
# Several filaments are combined to form a yarn.
# As fibers are combined and wrapped into the reel, twist can be added to hold the filaments together.
★ Adding twist is referred to as ‘throwing’ – resulting yarn is called thrown yarn
★ The type of yarn and amount of twist relate to the fabric produced.
★ The simplest type of thrown yarn is a ‘single’ – 8 filaments are twisted together to form a yarn
★ Used for filling yarns in silk fabrics, singles can have 2 or 3 twists per inch
'Silk Noils (silk waste):' produced from the inner portions of the cocoon. It is degummed (sericin is removed) and spun like other staple fiber. Or it can also be blended with another staple fiber and is spun into yarn.
'Wild Silk' production is not controlled. Cocoons are harvested after the moth has matured, so silk cannot be reeled – it must be spun.
'Types of Wild Silk:'
★ Tussah (most common)
★ Dupioni
★ Momme (standard way to describe silk fabrics)
Producers
With over 30 countries producing silk the major producers are:
★ China (54%)
★ India (14%)
★ Japan (11%)
See also
★
Mommes, the traditional density unit for silk.
★
Rayon
★
Silk Road
★
Spider silk (with a discussion of synthetic silk)
★
Jim Thompson, pioneer of Thailand's silk industry.
★
Marisol Deluna,
American fashion designer known for her use of silk
★
Rajshahi Silk, famous silk clothing (especially
saree) of
Bangladesh
★
Silk in the Indian subcontinent
★
History of silk
Footnotes
1. Chinese archaeologists make ground-breaking textile discovery in 2,500-year-old tomb
2. Hill, John E. 2003. "Annotated Translation of the Chapter on the Western Regions according to the ''Hou Hanshu''." 2nd Edition. Appendix A. [2]
3. Annals, , , Tacitus, , ,
4. Silk: Why It Is Haram for Men
5. Down and Silk: Birds and Insects Exploited for Fabric
6. History of Sericulture, Culture Entomology Digest 1
References
★ Good, Irene. 1995. “On the question of silk in pre-Han Eurasia” ''Antiquity'' Vol. 69, Number 266, December 1995, pp. 959-968
★ Hill, John E. 2004. ''The Peoples of the West from the Weilue'' 魏略 ''by Yu Huan'' 魚豢'': A Third Century Chinese Account Composed between 239 and 265 CE.'' Draft annotated English translation. Appendix E.
[3]
★ Kuhn, Dieter. 1995. “Silk Weaving in Ancient China: From Geometric Figures to Patterns of Pictorial Likeness.” ''Chinese Science'' 12 (1995): pp. 77-114.
★ Liu, Xinru. 1996. ''Silk and Religion: An Exploration of Material Life and the Thought of People, AD 600-1200''. Oxford University Press.
★ Sung, Ying-Hsing. 1637. ''Chinese Technology in the Seventeenth Century - T'ien-kung K'ai-wu''. Translated and annotated by E-tu Zen Sun and Shiou-chuan Sun. Pennsylvania State University Press, 1966. Reprint: Dover, 1997. Chap. 2. Clothing materials.
★ Kadolph, Sara J. Textiles. 10th ed. Upper Saddle River: Pearson Prentice Hall, 2007. 76-81.
External links
★
Silkworm rearing (with photos)
★
★ class=wikiexternal target=_blank>/Sericum.html References to silk by Roman and Byzantine writers
★
Silk production and handloom weaving
★
Comparison of Silks for Embroidery - article with photos comparing different silks used in hand embroidery
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