There are two main types of fibres:
1. Natural Fibres - those from nature.
Examples of Natural Fibres include: Cotton, Flax, Jute, Hemp, Wool, Hair (alpaca, camel and cashmere), silk.
2. Manufactured Fibres - those made by man. Within Manufactured Fibres you have Natural Polymer Fibres (derived from natural fibres, but undergone extensive processing) and Synthetic Polymers (formed entirely by chemical synthesis).
Examples of Manufactured Fibres include: viscose, modal, triacetate, acetate, lyocell, nylon, polyester, acrylic, elastane, polypropylene etc.
Silk is a type of natural fibre. This means it is 100% derived from natural sources and produced by nature. As such it is biodegradable, meaning it breaks down and goes back into the soil.
Silk is a fibre like no other - historically it was prized by Roman and Arabian aristocrats for it's unmatched beauty, durability and comfort. The rarity and secrecy around how the fabric was made, made it all the more precious. Silk fabrics were one of the most valued commodities that travelled westward along the Silk Road from China to the west. It was worth as much in weight as gold and often used as a currency.
But how is silk made?
First of all there are two types of silk:
1. Cultivated Silk - produced by the caterpillar of the Bombyx Mori moth
2. Wild Silk - produced by the caterpillar of the Antheraea type moth
Most silk is the cultivated variety as this moth produces in a continuous filament form, thus making it easier to combine and spin into a yarn to be used to make fabrics.
Silk is made from the saliva of the silkworm (Bombyx Mori). It spins silk from spinnerets on its head in a continuous filament to create a cocoon, a protective layer to cover itself during the transformation into a moth.
There are a few different ways of harvesting the cocoon for silk. The most common process and one that has been used since the beginning of time, is called sericulture. This process involves farmers creating an artificial bed for the moths to lay their eggs on. These eggs hatch and become larvae. Next they are fed a steady diet, generally mulberry leaves, and after roughly 35days of growing in size they are ready to spin their cocoons. Once the cocoon process is complete, the cocoon is boiled or steamed alive. Some cocoons are kept to turn into moths to repeat the process. But most are boiled/steamed to harvest the silk. The cocoon is boiled or steamed to blunt a natural chemical in the fibre called sericin which makes the silk fibre hard and results in a much rougher fabric.
Due to the cruelty around boiling the caterpillar inside a cocoon to harvest the silk, other methods have been developed in more recent times. In China - the largest and oldest producer of silk, the silkworms inside the cocoon are removed and eaten. Limiting the bio-waste and providing a natural food source.
In India a type of silk known as Ahimsa Silk, is made by allowing the worms to hatch from their cocoon or sometimes the cocoons are cut and the pupae are removed. However, due to the natural build up of sericin the cocoons become harder. Therefore the silk harvested through this method is harder than traditional silk. The Ahimsa method of producing silk also produces a lower yield, with broken filaments, which means this type of silk is harder to produce and therefore more expensive.
Silk fibre has a smooth appearance, soft lustre and a warm handle. Its draping qualities are excellent, especially used in lightweight fabrics such as a chiffon. The ability of silk fabrics to change colour when viewed from different angles, make sit a highly sought after and unique fibre The fibre has a high tensile strength so is suitable to be used in sheer fabrics as it provides adequate strength. Care must be given in washing silk fabrics, as there is a reduction in tensile strength when the fibre is wet. Therefore hand washing is recommended and care taken when laundering.
Silk also has high antimicrobial properties, like that of merino wool, and is starting to be used widely throughout the medical field.
Silk is regarded as one of the finest natural fibres. It is a luxury fibre due to its smooth appearance and soft lustre as well as its rarity.
To read about other natural fibres such as Wool, Cotton and Flax click here.