Difference between revisions of "Silk" - New World Encyclopedia

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[[Image:Meyers b14 s0826a.jpg|thumb|Four of the most important domesticated silk worms, together with their adult moth forms, [[Meyers Konversations-Lexikon]] (1885-1892)]]
 
[[Image:Meyers b14 s0826a.jpg|thumb|Four of the most important domesticated silk worms, together with their adult moth forms, [[Meyers Konversations-Lexikon]] (1885-1892)]]
 
[[Image:Thai silk.jpg|thumb|Thai silk]]
 
[[Image:Thai silk.jpg|thumb|Thai silk]]
'''Silk''' is a fine, soft and yet strong [[protein|proteinaceous]] [[fiber]] that is naturally produced by certain [[arthropod]]s and with some forms, particularly that produced by the [[mulberry]] [[silkworm]] ''[[Bombyx mori]]'', [[weaving|woven]] into important and luxurious [[textile]]s. Silk is mostly composed of the insoluble protein fibroin, coated by a smaller amount of a water-soluble protective gum (sericin), as well as including small amounts of other substances. The shimmering appearance of fine silk is due to the triangular [[prism (optics)|prism]]-like structure of the silk fiber, which allows silk cloth to refract incoming light at different [[angle]]s, thus producing different colors. In addition to clothing, silk is used for a variety of uses, including [[upholstery]], wall coverings, [[Carpet|rug]]s, [[bedding]] and wall hangings.
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'''Silk''' is a fine, soft and yet strong [[protein|proteinaceous]] [[fiber]] that is naturally produced by certain [[arthropod]]s, and with some forms, particularly that produced by the [[mulberry]] [[silkworm]] ''[[Bombyx mori]]'', [[weaving|woven]] into important and luxurious [[textile]]s. Silk is mostly composed of the insoluble protein fibroin, coated by a smaller amount of a water-soluble protective gum (sericin), as well as including small amounts of other substances. The shimmering appearance of fine silk is due to the triangular [[prism (optics)|prism]]-like structure of the silk fiber, which allows silk cloth to refract incoming light at different [[angle]]s, thus producing different colors. In addition to clothing, silk is used for a variety of uses, including [[upholstery]], wall coverings, [[Carpet|rug]]s, [[bedding]] and wall hangings.
  
 
While the best-known and commercially important silk is obtained from the [[Pupa#Cocoon|cocoon]]s of the the domesticated [[insect]] ''[[Bombyx mori]]'', commercial silks also are produced by two giant silkworms in the Saturnidae family, ''Samia cynthia'' and ''Antheraea pernyi''. ''Bombyx mori'' feeds solely on the leaves of [[mulberry]] trees and produces the finest, most lustrous fiber, while ''Samia cynthia'' feeds on the leaves of the ''Ailanthus'' genus and produces a coarse but more durable and cheap silk, and ''Antheraea pernyi,'' the Chinese tussah moth, is a major producer of wild silk (tussah silk), which is more difficult to dye. Silks are mainly produced by the [[larva]]e of insects undergoing [[Metamorphosis#Insect metamorphosis|complete metamorphosis]], but also by some adult insects such as [[webspinner]]s. Silk production is especially common in the [[Hymenoptera]] ([[bee]]s, [[wasp]]s, and [[ant]]s), and is sometimes used in nest construction. Other types of [[arthropod]]s produce silk, most notably various [[arachnid]]s such as [[spider]]s.
 
While the best-known and commercially important silk is obtained from the [[Pupa#Cocoon|cocoon]]s of the the domesticated [[insect]] ''[[Bombyx mori]]'', commercial silks also are produced by two giant silkworms in the Saturnidae family, ''Samia cynthia'' and ''Antheraea pernyi''. ''Bombyx mori'' feeds solely on the leaves of [[mulberry]] trees and produces the finest, most lustrous fiber, while ''Samia cynthia'' feeds on the leaves of the ''Ailanthus'' genus and produces a coarse but more durable and cheap silk, and ''Antheraea pernyi,'' the Chinese tussah moth, is a major producer of wild silk (tussah silk), which is more difficult to dye. Silks are mainly produced by the [[larva]]e of insects undergoing [[Metamorphosis#Insect metamorphosis|complete metamorphosis]], but also by some adult insects such as [[webspinner]]s. Silk production is especially common in the [[Hymenoptera]] ([[bee]]s, [[wasp]]s, and [[ant]]s), and is sometimes used in nest construction. Other types of [[arthropod]]s produce silk, most notably various [[arachnid]]s such as [[spider]]s.
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===Physical properties===
 
===Physical properties===
Silk fibres from the ''Bombyx mori'' silkworm have a [[triangle|triangular]] [[Cross section (geometry)|cross section]] with rounded corners, 5-10 [[μm]] wide.  The fibroin-heavy chain is composed mostly of beta-sheets, due to a 59-mer aminoacid repeat sequence with some variations.<ref>"Handbook of Fiber Chemistry", Menachem Lewin, Editor, 3rd ed., 2006, CRC press, ISBN 0-8247-2565-4</ref> The flat surfaces of the fibrils reflect [[light]] at many angles, giving silk a natural shine.  The cross-section from other silkworms can vary in shape and diameter: crescent-like for ''Anaphe'' and elongated wedge for ''tussah''.  Silkworm fibres are naturally extruded from two silkworm glands as a pair of primary filaments (brin), which are stuck together, with sericin proteins that act like [[glue]], to form a [[bave]]. Bave diameters for tussah silk can reach 65 μm. See cited reference for cross-sectional SEM photographs.<ref>"Handbook of Fiber Chemistry", Menachem Lewin, Editor, 2nd ed.,1998, Marcel Dekker, pp. 438-441, ISBN 0-8247-9471-0</ref>
+
Silk has a smooth, soft texture that is not slippery, unlike many [[synthetic fiber]]s.  
  
Silk has a smooth, soft texture that is not slippery, unlike many [[synthetic fiber]]s.
+
Silk is one of the strongest natural fibers but loses up to 20% of its strength when wet. It has a good [[moisture regain]] of 11%.  Its [[Elasticity (physics)|elasticity]] is moderate to poor: if elongated even a small amount, it remains stretched.  It can be weakened if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty.
  
Silk is one of the strongest natural fibres but loses up to 20% of its strength when wet.  It has a good [[moisture regain]] of 11%.  Its [[Elasticity (physics)|elasticity]] is moderate to poor: if elongated even a small amount, it remains stretched.  It can be weakened if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty.
+
Silk is a poor conductor of [[electricity]] and thus susceptible to [[static cling]].
  
Silk is a poor conductor of [[electricity]] and thus susceptible to [[static cling]].
+
Silk fibers from the ''Bombyx mori'' silkworm have a [[triangle|triangular]] [[Cross section (geometry)|cross section]] with rounded corners, 5-10 [[μm]] wide.  The fibroin-heavy chain is composed mostly of beta-sheets, due to a 59-mer amino acid repeat sequence with some variations.<ref name="Lewin3rd">M. Lewin (ed.), ''Handbook of Fiber Chemistry, 3rd ed.'' (CRC press, 2006). ISBN 0824725654.</ref> The flat surfaces of the fibrils reflect [[light]] at many angles, giving silk a natural shine.  The cross-section from other silkworms can vary in shape and diameter: crescent-like for ''Anaphe'' and elongated wedge for ''tussah''.
  
Unwashed silk chiffon may shrink up to 8% due to a relaxation of the fibre macrostructure.  So silk should either be pre-washed prior to garment construction, or [[Dry cleaning|dry cleaned]][[Dry cleaning]] may still shrink the chiffon up to 4%Occasionally, this shrinkage can be reversed by a gentle steaming with a press cloth. There is almost no gradual shrinkage nor shrinkage due to molecular-level deformation.
+
Silkworm fibers are naturally extruded from two silkworm glands as a pair of primary filaments (brin), which are stuck together, with sericin proteins that act like [[glue]], to form a [[bave]].  Bave diameters for tussah silk can reach 65 μm. See cited reference for cross-sectional SEM photographs.<ref>M. Lewin (ed.), ''Handbook of Fiber Chemistry, 2nd ed.'' (Marcel Dekker, 1998). ISBN 0824794710.</ref>
  
Natural and synthetic silk is known to manifest piezoelectric properties in proteins, probably due to its molecular structure.<ref>{{Cite web|url=http://fs.tx.ncsu.edu/Past_Meetings/Spring_2003_Loughborough/papers/081-Ellison.pdf|title=Piezoelectricity in Natural and Synthetic Silks|accessdate=28 April 2010}}</ref>
+
Unwashed silk chiffon may shrink up to 8% due to a relaxation of the fiber macrostructure. So silk should either be pre-washed prior to garment construction, or [[Dry cleaning|dry cleaned]]. [[Dry cleaning]] may still shrink the chiffon up to 4%. Occasionally, this shrinkage can be reversed by a gentle steaming with a press cloth. There is almost no gradual shrinkage nor shrinkage due to molecular-level deformation.
  
 
Silkworm silk was used as the standard for the [[Units_of_textile_measurement#Denier|denier]], a measurement of [[linear density]] in fibers.  Silkworm silk therefore has a linear density of approximately 1 den, or 1.1 [[Units_of_textile_measurement#Tex|dtex]].
 
Silkworm silk was used as the standard for the [[Units_of_textile_measurement#Denier|denier]], a measurement of [[linear density]] in fibers.  Silkworm silk therefore has a linear density of approximately 1 den, or 1.1 [[Units_of_textile_measurement#Tex|dtex]].
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
!  Comparison of silk fibers<ref>{{Cite web|url=http://web.mit.edu/course/3/3.064/www/slides/Ko_spider_silk.pdf|title=Engineering Properties of Spider Silk|author=Frank K. Ko |coauthors=Sueo Kawabata, Mari Inoue, Masako Niwa|accessdate=9 July 2010}}</ref> !! Linear Density(dtex) !! Diameter (μm) !! Coeff. Variation
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!  Comparison of silk fibers<ref>F. K. Ko, S. Kawabata, M. Inoue, M. Niwa, S. Fossey, and J. W. Song, [http://web.mit.edu/course/3/3.064/www/slides/Ko_spider_silk.pdf "Engineering properties of spider silk,"] Retrieved February 12, 2011.</ref><ref>F. K. Ko, [http://books.google.com/books?id=QdjzOCnrED0C&pg=PA27&lpg=PA27&dq=ENGINEERING+PROPERTIES+OF+SPIDER+SILK+Frank+K.+Ko&source=bl&ots=G9jb4SGDBd&sig=XvzosJ4pIDap_dX7wa1zjUzou2Y&hl=en&ei=FaBWTeuYEMOclgfmuoGnBw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CCsQ6AEwAw#v=onepage&q=ENGINEERING%20PROPERTIES%20OF%20SPIDER%20SILK%20Frank%20K.%20Ko&f=false "Engineering properties of spider silk fibers,"] Chapter 3, pages 27-49, in F. T. Wallengberger and N. Weston, ''Plastics and Composites'' (Dordrecht, Netherlands: Kluwer Academic Publishers, 2004). ISBN 1402076436.</ref> !! Linear Density(dtex) !! Diameter (μm) !! Coeff. Variation
 
|-
 
|-
 
| [[Moth]]: ''[[Bombyx mori]]'' || 1.17 || 12.9 || 24.8%
 
| [[Moth]]: ''[[Bombyx mori]]'' || 1.17 || 12.9 || 24.8%

Revision as of 15:14, 12 February 2011


Four of the most important domesticated silk worms, together with their adult moth forms, Meyers Konversations-Lexikon (1885-1892)
Thai silk

Silk is a fine, soft and yet strong proteinaceous fiber that is naturally produced by certain arthropods, and with some forms, particularly that produced by the mulberry silkworm Bombyx mori, woven into important and luxurious textiles. Silk is mostly composed of the insoluble protein fibroin, coated by a smaller amount of a water-soluble protective gum (sericin), as well as including small amounts of other substances. The shimmering appearance of fine silk is due to the triangular prism-like structure of the silk fiber, which allows silk cloth to refract incoming light at different angles, thus producing different colors. In addition to clothing, silk is used for a variety of uses, including upholstery, wall coverings, rugs, bedding and wall hangings.

While the best-known and commercially important silk is obtained from the cocoons of the the domesticated insect Bombyx mori, commercial silks also are produced by two giant silkworms in the Saturnidae family, Samia cynthia and Antheraea pernyi. Bombyx mori feeds solely on the leaves of mulberry trees and produces the finest, most lustrous fiber, while Samia cynthia feeds on the leaves of the Ailanthus genus and produces a coarse but more durable and cheap silk, and Antheraea pernyi, the Chinese tussah moth, is a major producer of wild silk (tussah silk), which is more difficult to dye. Silks are mainly produced by the larvae of insects undergoing 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 arthropods produce silk, most notably various arachnids such as spiders.

Initially developed about 5000 years ago in China, for many years silk was a primary commodity traded by China with the West along the Silk Road, and the silk production process was a carefully guarded secret for thousands of years. Today, at least 70 million pounds of raw silk are produced each year, requiring nearly ten billion pounds of mulberry leaves. The annual world production represents 70 billion miles of silk filament, a distance well over 300 round trips to the sun.

Properties

Models in silk dresses at the MoMo Falana fashion show

Chemical properties

Silk emitted by the silkworm consists of two main proteins, sericin and fibroin, fibroin being the structural center of the silk, and serecin being the sticky material surrounding it. Fibroin is made up of the amino acids Gly-Ser-Gly-Ala-Gly-Ala and forms beta pleated sheets. Hydrogen bonds form between chains, and side chains form above and below the plane of the hydrogen bond network.

The high proportion (50%) of glycine, which is a small amino acid, allows tight packing and the fibers are strong and resistant to breaking. The tensile strength is due to the many interseeded hydrogen bonds, and when stretched the force is applied to these numerous bonds and they do not break.

Silk is resistant to most mineral acids, except for sulfuric acid, which dissolves it. It is yellowed by perspiration.

Physical properties

Silk has a smooth, soft texture that is not slippery, unlike many synthetic fibers.

Silk is one of the strongest natural fibers but loses up to 20% of its strength when wet. It has a good moisture regain of 11%. Its elasticity is moderate to poor: if elongated even a small amount, it remains stretched. It can be weakened if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty.

Silk is a poor conductor of electricity and thus susceptible to static cling.

Silk fibers from the Bombyx mori silkworm have a triangular cross section with rounded corners, 5-10 μm wide. The fibroin-heavy chain is composed mostly of beta-sheets, due to a 59-mer amino acid repeat sequence with some variations.[1] The flat surfaces of the fibrils reflect light at many angles, giving silk a natural shine. The cross-section from other silkworms can vary in shape and diameter: crescent-like for Anaphe and elongated wedge for tussah.

Silkworm fibers are naturally extruded from two silkworm glands as a pair of primary filaments (brin), which are stuck together, with sericin proteins that act like glue, to form a bave. Bave diameters for tussah silk can reach 65 μm. See cited reference for cross-sectional SEM photographs.[2]

Unwashed silk chiffon may shrink up to 8% due to a relaxation of the fiber macrostructure. So silk should either be pre-washed prior to garment construction, or dry cleaned. Dry cleaning may still shrink the chiffon up to 4%. Occasionally, this shrinkage can be reversed by a gentle steaming with a press cloth. There is almost no gradual shrinkage nor shrinkage due to molecular-level deformation.

Silkworm silk was used as the standard for the denier, a measurement of linear density in fibers. Silkworm silk therefore has a linear density of approximately 1 den, or 1.1 dtex.

Comparison of silk fibers[3][4] Linear Density(dtex) Diameter (μm) Coeff. Variation
Moth: Bombyx mori 1.17 12.9 24.8%
Spider: Argiope aurentia 0.14 3.57 14.8%


Cultivation

Silkworm is the larva or caterpillar of various species of moths, in particular, Bombyx mori the domesticated silkmoth, whose silk cocoons can be used in the production of silk.

Silkworm species vary in terms of the quality of silk they produce and the leaves they consume. Bombyx mori (Latin: "silkworm of the mulberry tree") of the of the Bombycidae family feeds solely on the leaves of mulberry trees and produces the finest, most lustrous fiber—the major source of commercial silk. Other silk producers include two giant silkworms in the Saturnidae family, Samia cynthia and Antheraea pernyi. Samia cynthia, the ailanthus silkmoth, feeds on the leaves of the Ailanthus genus and produces a coarse silk, but one that is more durable and cheaper than mulberry silk. Antheraea pernyi, the Chinese tussah moth, is a major producer of another variety of wild silk (tussah silk).


Wild silks, or tussah silks (also spelled "tasar"), are those 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, the wild silks 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. Wild silks also tend to be more difficult to dye than silk from the cultiva


This article is on Bombyx mori, which is very important economically as the producer of silk and has been domesticated to the point that it is entirely dependent on humans for its reproduction and no longer occurs naturally in the wild. Silk culture has been practiced for at least 5,000 years in China (Goldsmith et al. 2004).

While other Lepidoptera produce cocoons, only a few large Bombycidae and Saturniidae have been exploited for fabric production.

The cocoon of the domesticated silkworm is made of a single continuous thread of raw silk from 300 to 900 meters (1000 to 3000 feet) long. The fibers are very fine and lustrous, about ten micrometers (1/2500th of an inch) in diameter. They are made mostly of an insoluble protein (fibroin), coated by a smaller amount of a water-soluble protective gum (sericin), as well as including small amounts of other substances.

Using a rough figure of one kilometer of silk (about 3300 feet) per cocoon, ten unraveled cocoons could theoretically extend vertically to the height of Mt Everest. About 2,000 to 3,000 cocoons are required to make a pound of silk, or roughly 1,000 miles of filament (Palmer 1949).

At least 70 million pounds of raw silk are produced each year, requiring nearly ten billion pounds of mulberry leaves. The annual world production represents 70 billion miles of silk filament, a distance well over 300 round trips to the sun.

If the pupating moth is allowed to survive after spinning its cocoon, it will release proteolytic enzymes to make a hole in the cocoon so that it can emerge as a moth. This would cut short the threads and ruin the silk. Instead, commercially reared silkworm pupae are killed before the adult moths emerge by dipping them in boiling water, thus allowing the whole cocoon to be unraveled as one continuous thread. This allows a much stronger cloth to be woven from the silk. The water also makes the cocoons easier to unravel, loosing the gum part of the raw fiber. The pupae also may be pierced with a needle rather than boiling. Often, the silkworm itself is eaten or used for other purposes (fertilizer, fish food, etc.).

ted silkworm.



Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh mulberry leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a "figure 8" pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon. The silk farmers then kill most caterpillars by heat, leaving some to metamorphose into moths to breed the next generation of caterpillars.

Harvested cocoons are then soaked in boiling water to soften the sericin holding the silk fibers together in a cocoon shape. The fibers are then unwound to produce a continuous thread. Since a single thread is too fine and fragile for commercial use, anywhere from three to ten strands are spun together to form a single thread of silk.[5]


Production

The cultivation of silk is called sericulture. Over 30 countries produce silk, the major ones are China (54%) and India (14%).

To produce 1 kg of silk, 104 kg of mulberry leaves must be eaten by 3000 silkworms. It takes about 5000 silkworms to make a pure silk kimono.[6]:104

Top Ten Cocoons (Reelable) Producers — 2005
Country Production (Int $1000) Footnote Production (1000 kg) Footnote
Flag of People's Republic of China People's Republic of China 978,013 C 290,003 F
Flag of India India 259,679 C 77,000 F
Flag of Uzbekistan Uzbekistan 57,332 C 17,000 F
Flag of Brazil Brazil 37,097 C 11,000 F
Flag of Iran Iran 20,235 C 6,000 F
Flag of Thailand Thailand 16,862 C 5,000 F
Flag of Vietnam Vietnam 10,117 C 3,000 F
Flag of North Korea Democratic People's Republic of Korea 5,059 C 1,500 F
Flag of Romania Romania 3,372 C 1,000 F
Flag of Japan Japan 2,023 C 600 F
No symbol = official figure, F = FAO estimate, * = Unofficial figure, C = Calculated figure;

Production in Int $1000 have been calculated based on 1999-2001 international prices
Source: Food And Agricultural Organization of United Nations: Economic And Social Department: The Statistical Division


Uses

Silk filaments being unraveled from silk cocoons, Cappadocia, Turkey, 2007.

Silk's absorbency makes it comfortable to wear in warm weather and while active. Its low conductivity keeps warm air close to the skin during cold weather. It is often used for clothing such as shirts, ties, blouses, formal dresses, high fashion clothes, lingerie, pyjamas, robes, dress suits, sun dresses and kimonos.

Silk's attractive luster and drape makes it suitable for many furnishing applications. It is used for upholstery, wall coverings, window treatments (if blended with another fiber), rugs, bedding and wall hangings.[citation needed]

While on the decline now, due to artificial fibers, silk has had many industrial and commercial uses; parachutes, bicycle tires, comforter filling and artillery gunpowder bags.[citation needed]

A special manufacturing process removes the outer irritant sericin coating of the silk, which makes it suitable as non-absorbable surgical sutures. This process has also recently led to the introduction of specialist silk underclothing for children and adults with eczema where it can significantly reduce itch.[citation needed]


History

Woven silk textile from tomb no 1. at Mawangdui in Changsha, Hunan province, China, from the Western Han Dynasty, 2nd century B.C.E.
Landscape of quick water from high mountain by Zhao Zho, Ming Dynasty, 1611 C.E. Hand scroll, ink and colour on silk.


Wild silk

A variety of wild silks, produced by caterpillars other than the mulberry silkworm have been known and used in China, South Asia, and Europe since ancient times. However, the scale of production was always far smaller than that of cultivated silks. They differ from the domesticated varieties in color and texture, and cocoons gathered in the wild usually have been damaged by the emerging moth before the cocoons are gathered, so the silk thread that makes up the cocoon has been torn into shorter lengths. Commercially reared silkworm pupae are killed by dipping them in boiling water before the adult moths emerge, or by piercing them with a needle, allowing the whole cocoon to be unraveled as one continuous thread. This permits 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.

China

Silk fabric was first developed in ancient China,[7] with some of the earliest examples found as early as 3500 B.C.E.[8] Legend gives credit for developing silk to a Chinese empress, Lei Zu (Hsi-Ling-Shih, Lei-Tzu). Silks were originally reserved for the Kings of China for their own use and gifts to others, but spread gradually through Chinese culture and trade 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 2007, archeologists discovered intricately woven and dyed silk textiles in a tomb in Jiangxi province, dated to the Eastern Zhou Dynasty roughly 2,500 years ago.[9] 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 B.C.E.-220 C.E.).[9]

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 B.C.E.[10] 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 highest development was in China.

The Emperors of China strove to keep knowledge of sericulture secret to maintain the Chinese monopoly. Nonetheless sericulture reached Korea around 200 B.C.E., about the first half of the 1st century AD had reached ancient Khotan,[11] and by AD 300 the practice had been established in India.[citation needed]

Thailand

Silk is produced, year round, in Thailand by two types of silkworms, the cultured Bombycidae and wild Saturniidae. Most production is after the rice harvest in the southern 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 colours and styles. Most regions of Thailand have their own typical silks. A single thread filament is too thin to use on its own so women combine many threads to produce a thicker, usable fibre. They do this by hand-reeling the threads onto a wooden spindle to produce a uniform strand of raw silk. The process takes around 40 hours to produce a half kilogram of Thai silk.

Many local operations use a reeling machine for this task, but some silk threads are still hand-reeled. The difference is that hand-reeled threads produce three grades of silk: two fine grades that are ideal for lightweight fabrics, and a thick grade for heavier material.

The silk fabric is soaked in extremely cold water and bleached before dyeing to remove the natural yellow coloring of Thai silk yarn. To do this, skeins of silk thread are immersed in large tubs of hydrogen peroxide. Once washed and dried, the silk is woven on a traditional hand operated loom.[12]

Woven silk from Cambodia

India

Silk, known as "Paat" in Eastern India, Pattu in southern parts of India and Resham in Hindi/Urdu, has a long history in India. Recent archaeological discoveries in Harappa and Chanhu-daro suggest that sericulture, employing wild silk threads from native silkworm species, existed in South Asia during the time of the Indus Valley Civilization, roughly contemporaneous with the earliest known silk use in China.[13] Silk is widely produced today. India is the second largest producer of silk after China. A majority of the silk in India is produced in Karnataka State, particularly in Mysore and the North Bangalore regions of Muddenahalli, Kanivenarayanapura, and Doddaballapur.[14] India is also the largest consumer of silk in the world. The tradition of wearing silk sarees in marriages by the brides is followed in southern parts of India. Silk is worn by people as a symbol of royalty while attending functions and during festivals. Historically silk was used by the upper classes, while cotton was used by the poorer classes. Today silk is mainly produced 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 Pochampally 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 sarees. The sarees 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 sarees woven with traditional motifs. Mysore Silk Sarees, which are known for their soft texture, last many years if carefully maintained.

Ancient Mediterranean

The Gunthertuch, an 11th-century silk celebrating a Byzantine emperor's triumph

In the Odyssey, 19.233, when Odysseus, while pretending to be someone else, is questioned by Penelope about her husband's clothing, he says that he wore a shirt "gleaming like the skin of a dried onion" (varies with translations, literal translation here)[15] which could refer to the lustrous quality of silk fabric. The Roman Empire knew of and traded in silk. During the reign of emperor Tiberius, sumptuary laws were passed that forbade men from wearing silk garments, but these proved ineffectual.[16] Despite the popularity of silk, the secret of silk-making only reached Europe around AD 550, via the Byzantine Empire. Legend has it that monks working for the emperor Justinian I smuggled silkworm eggs to Constantinople in hollow canes from China. 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.

Middle East

Purchasing silkworm cocoons in Antioch, circa 1895.
Dress made from silk

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.[17] There are disputes regarding the amount of silk a fabric can consist of (i.e., whether a small decorative silk piece on a cotton caftan is permissible or not) for it to be lawful for men to wear but the dominant opinion of most Muslim scholars is that the wearing of silk for men is forbidden.

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 Armenian 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. 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.


Silk clothing in the Tacuinum Sanitatis (XIV century)

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. In 1717, John Lombe, visited Piedmont and returned to England with details of the Italian machines, and some Italian craftsmen. He was granted a fourteen year patent, and built Lombe's Mill in Derby. The King of Sardinia retaliated by prohibiting the export of raw silk. Nethertheless, in 1732 John Guardivaglio set up a silk throwing enterprise at Logwood mill in Stockport, and in 1744, Burton Mill was erected in Macclesfield and in 1753 Old Mill was built in Congleton.[18]. These three towns remained the centre of the English silk throwing industry until silk throwing was replaced by silk waste spinning. British enterprise also established silk filature in Cyprus in 1928. In England in the mid 20th Century, raw silk was produced at Lullingstone Castle in Kent. Silkworms were raised and reeled under the direction of Zoe Lady Hart Dyke. 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.[19] The most important cities for silk production in Italy were Como and Meldola [20] (Forlì).

North America

James I of England introduced silk-growing to the American colonies around 1619, ostensibly to discourage tobacco planting. The Shakers in Kentucky adopted the practice as did a cottage industry in New England.[21] In the 19th century 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).


Animal rights

As the process of harvesting the silk from the cocoon kills the larvae, sericulture has been criticized in the early 21st century by animal rights activists, especially since artificial silks are available.[22] Mohandas Gandhi was also critical of silk production based on the Ahimsa philosophy "not to hurt any living thing." This led to Gandhi's promotion of cotton spinning machines, an example of which can be seen at the Gandhi Institute. He also promoted Ahimsa silk, wild silk made from the cocoons of wild and semi-wild silk moths.[23] Ahimsa silk is promoted in parts of Southern India for those who prefer not to wear silk produced by killing silkworms.[24][25]

See also

  • Art silk
  • Byzantine silk
  • History of silk
  • International Year of Natural Fibres 2009
  • Mommes, the traditional density unit for silk.
  • Rayon
  • Silk in the Indian subcontinent
  • Silk Road
  • Silk waste
  • Spider silk (with a discussion of synthetic silk)
  • Tenun Pahang Diraja, famous woven silk fabric of Pahang, Malaysia.
  • Thai silk

References
ISBN links support NWE through referral fees

Notes
  1. M. Lewin (ed.), Handbook of Fiber Chemistry, 3rd ed. (CRC press, 2006). ISBN 0824725654.
  2. M. Lewin (ed.), Handbook of Fiber Chemistry, 2nd ed. (Marcel Dekker, 1998). ISBN 0824794710.
  3. F. K. Ko, S. Kawabata, M. Inoue, M. Niwa, S. Fossey, and J. W. Song, "Engineering properties of spider silk," Retrieved February 12, 2011.
  4. F. K. Ko, "Engineering properties of spider silk fibers," Chapter 3, pages 27-49, in F. T. Wallengberger and N. Weston, Plastics and Composites (Dordrecht, Netherlands: Kluwer Academic Publishers, 2004). ISBN 1402076436.
  5. Carrie Gleason: The Biography of Silk, page 12. Crabtree Publishing Company 2007.
  6. Fritz, Anne and Cant, Jennifer (1986). Consumer Textiles. Oxford University Press Australia. Reprint 1987. ISBN 0 19 554647 4.
  7. Silk: History. Columbia Encyclopedia Sixth Edition.
  8. Textile Exhibition: Introduction. Asian art.
  9. 9.0 9.1 Chinese archaeologists make ground-breaking textile discovery in 2,500-year-old tomb. People's Daily Online.. Retrieved 2007-08-26.
  10. Lubec, G. and J. Holaubek, C. Feldl, B. Lubec, E. Strouhal (1993-03-04). Use of silk in ancient Egypt. Nature 362 (6415): 25. (also available here)
  11. Hill, John E. 2003. "Annotated Translation of the Chapter on the Western Regions according to the Hou Hanshu." 2nd Draft Edition. Appendix A. [1]
  12. About Thai silk from World of Thai Silk (commercial)
  13. (2009). New evidence for early silk in the Indus civilization. Archaeometry 50: 457.
  14. Silk city to come up near B’lore, Deccan Herald, 16 October 2009.
  15. Odyssey 19 233-234: τὸν δὲ χιτῶν' ἐνόησα περὶ χροῒ σιγαλόεντα, οἷόν τε κρομύοιο λοπὸν κάτα ἰσχαλέοιο· = "And I [= Odysseus
  16. Tacitus. Annals. ISBN 0521315433. 
  17. Silk: Why It Is Haram for Men (2003-09-23). Archived from the original on 2007-03-02. Retrieved 2007-01-06.
  18. Callendine 1993
  19. Rayner 1903
  20. The Silkworm Museum, Meldola
  21. Mansfield Historical Society (2008). Retrieved 2009-03-30.
  22. Down and Silk: Birds and Insects Exploited for Fabric. PETA. Retrieved 2007-01-06.
  23. "Mahatma Gandhi: 100 years", 1968, p. 349
  24. Silk Moths Fly Free Kusuma Rajaiah's Ahimsa project.
  25. Silk saree without killing a single silkworm Another article about Rajaiah and his methods.
Bibliography
  • Callandine, Anthony (1993). Lombe's Mill: An Exercise in reconstruction. Industrial Archaelogy Review XVI (1).
  • 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 Weilüe 魏略 by Yu Huan 魚豢: A Third Century Chinese Account Composed between 239 and 265 C.E. Draft annotated English translation. Appendix E.
  • 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.
  • Liu, Xinru (2010). The Silk Road in World History. Oxford University Press. ISBN 978-0-19-516174-8; ISBN 978-0-19-533810-2 (pbk).
  • Rayner, Hollins (1903). Silk throwing and waste silk spinning. Scott, Greenwood, Van Nostrand. 
  • 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.

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