Silk
Dee Dee Yang
DES 40A
Christina Cogdell
March 11, 13
Silk: Raw Materials and Production
Introduction:
Silk is a delicate fabric that has been prized for centuries. The history of silk began in China and continued to spread throughout the world. China and India remain the biggest producers of this material. The history of silk showed that it was the finest material that could ever be obtained; therefore the people who possessed silk were most often those who could afford it, royalties and wealthy individuals. Through wars, secrecy and trade, silk initiated greed and desperation from the different countries to gain knowledge of the secret to producing such a fine piece of work. Silk has always been a desired fabric. Even today, silk remains the more favorite material, but the expense of it inhibits consumers from purchasing it regularly. That is why silk is only often found in expensive and designer wedding gowns.
Silk is largely valued because of the sensual luxurious feel that the material has. It also has other features that make it more preferred than other materials; it is the most comfortable and absorbent. Not only does the physical properties make it treasured, the also silk production that manufactures the silk is labor intensive and time consuming. Its explicitness makes it desirable.
The more work that’s put into making a material such as silk, the more valuable it is. Silk has always been the production that labored the most skilled workers. There are many steps of the production process that have different functions, but all add up to being very important in the development of silk. The different steps that contribute to the finished product include, first off, having the raw materials to begin the creation, having the machineries or manual laborers to process the silk, and lastly the manufacturing of silk fabric that turn the silk thread into fabrics that we wear.
Raw Materials:
It was said that the origin of silk production dated back to 6000BC when china’s empress Xi Ling-Shi went for a stroll in the mulberry garden and spotted glistening threads from cocoons. Other versions of the story stated that a cocoon dropped into her tea, and the thread started unraveling into a long silk thread. Either way, the discovery of silk began the practice of sericulture and the silk industry. The raw material that was needed for this was a small creature called the silkworm.
The creature that gained popularity in the textiles industries is known as the silkworm. There are different types of silkworms, but the one that is most commonly used in sericulture is the Bombyx Mori, the silkworm that feeds on mulberry leaves. The Bombyx Mori moth is the mature stage of the silkworm. This moth embodies the ending as well as the beginning of the life cycle of the silkworm. After the female moth is mated with a male moth, it lays hundreds of eggs. The female moth does not have a long life as a winged insect; after giving birth, the female moth dies. Luther Hooper gives a brief explanation of the life span of the female Bombyx Mori moth,
“The moth only lives a very few hours after all this preparation. Its only business is to arrange for the next generation of its kind. It never eats, for its moth is atrophied; it seldom, if ever, uses its wings, except to flutter weakly. The female just lays her eggs and then dies, a melancholy victim to the centuries of domestication and specialization in (Hooper 11).”
After being bred for the purpose of cultivation, the female moth has no other usage other than to reproduce. Although it dies a sad death, the female moth leaves behind the next generation of eggs, which marks the beginning of a new cycle.
The silkworm stage is the longest stage of the insect’s life. In the silkworm cultivation farm, sericulture takes place. Sericulture refers to the rearing of the silkworm for the purpose of producing silk. During the life cycle of the Bombyx Mori larvae, it continuously feeds on mulberry leaves for a few days until it becomes too large for its skin. It sheds that layer of skin and continues to eat and grow. It does this about four times within two months and eventually grows to 3 inches. When it is full grown, the caterpillar stops eating and changes its skin color. This is a sign that the inset is ready for the next stage, the cocoon spinning stage.
The cocoon is the very important part of the silk production. The general term refers to the protective casing that is spun by many insects to protect themselves as pupas. The cocoon that we are most familiar with is the one built by the caterpillar to enclose its transformation into a butterfly. One that we are not quite familiar with is a silkworm’s cocoon that protects it during its transformation into a moth. This particular type of cocoon happens to be the most valued cocoon in the textile industry because if its distinct features. The characteristics of these cocoons are only produced from the silkworms because they produce a protein called sericin and fibroin. Warren Pharaoh Seem discusses this aspects of the cocoon in his book “Raw Silk Properties: Classification of Raw Silk and Silk Throwing.”
“The cocoon fiber consists of two filaments, which issue from two small orifices in the head of the worm in a glutinous state and harden immediately on exposure to the air. From 17 to 25% of this fiber is silk gum or glue called sericin, and the remaining portion is the real fiber called fibroin (Seem 18).”
The sericin is produced from the fibroin apparatus in the silkworm gut. The fibroin apparatus has a reputation of being strong as well as insoluble in water, and have been used by fishermen as a fishing line (Hooper 9). The production of sericin in this organ is very significant because it allows for a strong fiber during the cocoon making stage. The mulberry leaves chemical composition also contributes to the characteristics of the spun fiber. The strength of this fiber is desired by the textile industry, and thus during the cocoon stage, the life of the silkworms end in order to proceed with obtaining the silk. The production of silk continues, but without the life of the worms.
Rearing Process:
One of the main factors that contribute to a successful production of silk is the rearing of the silkworms. During the rearing stage, the silkworms must be in perfect climatic conditions, fed properly, and staged correctly during the various stages of its growth.
During the egg stage, the worms must be kept in cool temperatures, 25-degree Celsius, and after six to twelve weeks, the eggs will hatch. There are different methods that are used during the rearing of these worms. One of which is called the “Chawki Rearing”. For this particular method, it requires ideal environmental conditions, and fresh mulberry leaves. Once the eggs hatch, the larvae will need to be fed an abundant amount of mulberry leaves. After they hatch, it is necessary to place them in trays to grow. While the worms are growing, they should not be in a crammed area. Dr. John Feltwell expressed in his book “Story of Silk”,
“An Italian experimented went further and noted that from 1 oz. of eggs, the first stage of caterpillar needs 8 square feet, the second 15 square feet, the third 35 square feet, the fourth 82 square feet and the fifth 200 square foot (Feltwell 39-40).”
It is also crucial to continuously change the trays to prevent fecal wastes to develop diseases; these silkworms are very vulnerable to diseases. To ensure that the worms are free from infections, lime powder is dusted over the worm beds to keep them dry (Ignousoa). It is also important to constantly add new mulberry leaves so the worms are being fed at all time.
When the caterpillars are ready for the cocoon stage, they will change colors. This indicates that they will need to be placed in a different environment. The term for the new housing is called mountages. Mountages are different from trays because they contain small openings separated by walls; this allows the worms to spin their cocoons. There are several types of mountages: traditional bamboo, plastic, and Japan type rotary cardboard mountages (Ignousoa). During this time, the worms will spin their cocoons; the worms must be undisturbed. This stage is the desired stage of the manufacturers because they want to obtain the silk from the cocoons.
Processing the silk:
When the cocoons are couple of weeks in is when the manufacturers want to obtain them for the silk. The cocoons are taken and placed in reeling machines to extract the silk fiber, which is a long continuous silk thread. The types of reeling machines that are used include the Indian Charkha machine, the Chinese boiling and reeling machine and several others. The Chinese boiling and reeling machine contains features that are necessary in gathering the thread. The machine contains a small tank that holds boiling water, a rod with holes to pull together several threads at once, and a wheel that winds the reeled thread into a roll.
The boiling water tank has many purposes. For one, the heat kills the creature inside the cocoon (Seem 115). It also helps loosen the sericin so that the reeling would be easier. The purpose of the rod and the holes is so that several threads could be reeled in at once. The small holes bring together separate threads from different cocoons and are twisted, or crossieur, at a point. This twisting occurrence is essential because it compresses several threads together. The sericin fuses the fibers together. The wheel is used to hold the reeled thread (Hooper 35-36). After that, the silk threads are bundled up onto bobbins and spindles; the thread is ready to use in making fabrics. The term that is used when turning the silk into yarn is called “throwing”. In throwing, there are three forms of silk threads: singles, which are untwisted, tram, which are twisted and doubled, and organzine, which are made of single’s twisted one way. Once the silk threads have been bundled up, they are ready to be imported to any silk merchants to produce clothing.
Manufacturing of silk garments:
After the threads are prepared, the next step is turning it from silk thread to varying silk works. During the fabrication of silk, it undergoes dyeing and weaving. After it becomes fabric, it is used to produce garments, wedding dresses, draperies, and etc.
The natural dyes of the silk threads are pure white and pure yellow. This varies from the different types of silkworms. In terms of the dyeing process, vegetable dyes were used to color the silk in the past. In recent times, manufacturers began using synthetic dyes; however, they are interested in returning to the usage of natural dyes (Feltwell 113). Today, the dyes that are used are acid dyes, metal-complex dyes, reactive dyes and etc. The dying process requires a well maintained pH, good quality water and proper duration of dyeing and drying in order for the coloration to turn out well. D. Sargunamani, Jayanta Ghose and Dinesh Tomar explain why these dyes are fit for the silk material,
“The exceptional capacity to absorb moisture from the air, the comparatively simple and orderly arrangement of fibroin molecular structure, and the abundance of hydrogen bonds and electrostatic bonds render silk fiber an ideally suited substrate with a very good dye affinity (Sargunamani).”
In Varanasi, the procedure for dying is manual. They use their hands and dye-tubs to dye the silk. During the procedure, the silk is soaked in the dye for a certain amount of time. After they are soaked, they are squeezed to remove the access water. After that, they threads are left to dry. After the dyeing process, the silk threads are ready to be turned into gowns, clothing, and other uses.
When the silk is a yarn, it is weaved into fabric like any other yarn. However, since silk is very delicate, it requires more specialized looms. In the past, the Jacquard loom was invented to be used for silk because of its fragility. Today, power-looms are used; however, traditional looms are still used too. In rural Varanasi India, old-fashioned handlooms are used to make their traditional “sari”. Different types of weaves create different types of looks that we see in silk objects.
Conclusion:
Sericulture has had an impact on the textile industry for centuries. After the discovery of silk in China, merchants from all over the world tried to get their hands on silk production so they could produce it on their own. Today, China and India remain the largest producers of silk. Today, we see designer wedding gowns on the market and we long for it but cannot afford it. The high expense of the material is due to the hard labor that has been put into the production process. In rural countries, the production of silk employs hundreds of poor laborers and that is very beneficial. However, the growing production of silk has contributed to the toxic pollutions that the world faces today. Although, the finished products of sericulture are luxurious, it also raises a problem that should be dealt with.
Citations:
Hooper, Luther. Silk: Its Production and Manufacture. Pitman & Sons, 1911. 126 pages. Web. Obtained 12, March 2013.
Seem, Warren Pharoah. Raw Silk Properties: Classification of Raw Silk and Silk Throwing. Silk Publishing Company, 1922. 367 pages. Web. Obtained 12, March 2013.
Sargunamani, D., Jayanta Ghose & Dinesh Tomar. Commercial Silk Dyeing Method at Varanasi. www.fibre2fashion.com, 2011. Web. Obtained 12, March 2013.
Feltwell, Dr. John. The Story of Silk. Alan Suttun Publishing, 1990. Print. Obtained 13, March 2013.
Igounsoa. “Silk Rearing-1.” Youtube. Web. Obtained 12, March 2013