Natural silk finds its origin in China, and can be traced back more than 4,000 years to the time of the Yellow Emperor, when people first began to domesticate silkworms and use the silk to make clothing. Pure silk is known in China as “the fabric of royalty”. The uniqueness of silk’s exquisite beauty has long been admired by ancient and modern peoples alike. Pure silk is made from a protein fibre called fibroin, which contains more than 18 amino acids beneficial to the human body.
The unit of measurement for pure silk is momme weight (mm). 1 momme is equivalent to 4.3056 g/m², and the greater the momme weight, the thicker and heavier the material will be. Although the price of pure silk increases along with the momme weight, this does not automatically mean that a heavier weight is better. This is because it is more important to retain the characteristic delicate and lightweight feel of the fabric when making certain products. Pure silk nightclothes are mainly produced using 19mm (momme) silk. Those of an even higher quality may go up to a momme weight of 22mm. Nowadays there are occasionally nightclothes made from silk greater than 22mm. When it comes to bedsheets and covers, it is more typical to see 19mm as the standard with anything up to 22mm already considered at the high end for a set of pure silk bed covers.
Natural silk is composed of sericin and fibroin, made up of 18 different amino acids in varying ratios along with empty space. It is a type of protein fibre. Sericin is found on the outside with fibroin on the inside, and these two are very closely interlinked. Sericin exists in a loose structure which causes it to have a course feel to touch, and because of this it needs to go through a process of degumming. The structure of fibroin is very tight, which gives it a rich, soft appearance and pearlescent lustre. The result is a fabric that is beautifully soft and smooth to touch while still feeling full and substantial, with an exceptionally high standard of elasticity and flexibility. It is extremely absorbent and breathable, and is very good at protecting and caring for your skin. Natural silk is a protein fibre, and rugs woven from natural silk are helpful in absorbing ultraviolet rays. As it is a multiporous material, natural silk is also able to provide a high degree of insulation, absorbency and breathability, and is good for wicking away moisture, and protecting and caring for your skin in several different ways.
It is important to note that natural silk is a very delicate material, and needs to be carefully looked after. In order to protect the protein fibres from damage, care must be taken not to allow it to become creased under heavy objects or to rub against rough surfaces.
Caring for Pure Silk
Washing: Silk clothing has been carefully woven using a process that protects the delicate proteins that make up the fibres. Scrubbing with anything that has a rough surface or using a washing machine for cleaning are not advised. Instead the clothing should be immersed in cold water for 5-10 minutes and gently rubbed using a special low-foaming detergent for cleaning silk, or a neutral pH soap (If you are cleaning a small item such as a silk scarf, then the same method can be followed using a little shampoo instead). Pure silk clothing which has been coloured can then be repeatedly rinsed under fresh water.
Airing: After cleaning, it is not advised to allow pure silk clothing to dry in the sun, and it especially should not be tumble dried. Generally the best method is to leave it to dry naturally in a dark airing cupboard. The ultraviolet rays in sunlight can easily cause yellowing, fading and ageing in natural silk products. Silk clothing should not be wrung out after washing, and instead should be gently unfolded and left to dry inside-out. Once it is mostly dry, the clothing can be ironed or laid flat.
Ironing: Clothing made from pure silk is not as good at resisting creasing as artificial fabrics. In China there is a saying, “If it doesn’t crease, then it’s not real silk”. After washing, the clothing will need to be ironed to remove the creases and restore the silk to its graceful smoothness. When ironing, the clothing should first be allowed to mostly dry out and then evenly misted with a water spray. After 3-5 minutes it can then be ironed, making sure that the temperature of the iron does not exceed 150°c. The iron should not come into direct contact with the surface of the silk so as to avoid scorching.
Storing: Delicate clothing made from pure silk such as underwear, shirts, trousers, skirts, nightwear etc. should first be washed and ironed before storing. Clothing which is more difficult to clean such as winter or autumnwear, silk padded jackets, Hanfu costumes, or Cheongsam dresses should be dry-cleaned and ironed flat, so as to prevent the growth of mould or damage from insects. Ironing also acts as a disinfectant and a way to control pests. The case or wardrobe in which the clothes are to be stored should be kept clean and tightly closed, so as to avoid the accumulation of dust and dirt.
The Benefits of Pure Silk
Natural silk is a non-polluting naturally occuring fibre. No other fibres or artificial fabrics can compare to the exquisite beauty and unparalleled prestige of pure silk, but what actually are the unique benefits it offers?
- Comfort: Pure silk is composed of protein fibres which have an excellent bio-compatibility with the human body. Its smooth surface has the lowest friction coefficient against the human body of any fabric; a mere 7.4%. When the smooth texture of silk comes into contact with delicate skin, it naturally conforms to the contours of the human body, comfortably resting in such a way as to protect every inch of skin with its unique softness.
- Moisture responsiveness: Silk protein fibres are rich in hydrophilic radicals such as amines (-NH2) and glycines, and its multiporous structure allows for water molecules to be easily dispersed. This means that the silk can both expel moisture into the air and draw moisture from the air to maintain a constant level of dryness. Under normal temperatures, silk can help skin to maintain its level of moisture and will not cause skin to become overly dry. When wearing silk in the summer, it will quickly disperse any perspiration and regulate excess heat, ensuring that you stay feeling cool and refreshed. Because of these special properties, silk products are very suitable for direct contact with the human body. Silk is not only able to disperse excess heat, it is also a great insulator. Its ability to maintain a constant temperature is due to the multiporous lattice structure of the fibres. Within a single silk fibre there are many tiny fibres which themselves are made up of even smaller fibres. Although silk appears to be solid, more than 38% of it is actually made up of empty pockets. A large amount of air is contained within these pockets which prevents the loss of heat. This is what makes silk an excellent insulator.
- Sound and Dust Absorption: Pure silk fabrics are highly porous, which makes them very good at absorbing sound and air. Because of this, apart from making clothes, silk can also be used for room decorations such as silk rugs, tapestries, curtains, wall hangings etc. Decorating a room with real silk products will not only help to keep the room spotlessly clean, it will also promote a calm and serene environment. As natural silk is able to balance moisture, absorb gas, and is multiporous, it can regulate both the temperature and the humidity within a room, and is helpful in reducing harmful gases, dust, and microorganisms .
- Heat Tolerance: Pure silk fibres have a small thermal alteration index and are relatively resistant to heat. When heated to 100°c, there is only a ~5-8% occurrence of embrittlement. In the vast majority of synthetic fibres, the thermal alteration index is ~4-5 times greater than that of silk. The burn temperature of natural silk is ~300-400°c, and it is hard to ignite as a fabric. Synthetic fibres on the other hand have a burn temperature of ~200-2600°c and are easily ignited. This means that not only are natural silk furnishings helpful in reducing noise, controlling dust, and maintaining the temperature in a room, they are even useful for preventing fire.
- Ultraviolet Ray Resistant: Tryptophan and tyrosine contained in silk protein can absorb ultraviolet rays, so silk is relatively good at resisting ultraviolet (UV) radiation, which is especially harmful to human skin. The silk itself can of course experience chemical changes after exposure to UV rays, and as a result silk products can easily yellow from exposure to sunlight.
- Health Promoting: Silk is hailed as “the fabric of royalty” and “the fabric for health” in China. Pure silk is made up of protein fibres, which contain 18 amino acids essential for human health. These are very similar to the amino acids contained in human skin, and can help the skin to maintain metabolism in its surface layers while staying moist and smooth. They work just like a second skin. Wearing pure silk nightclothes is not only a good way to prevent UV radiation, resist toxic gases, and repel germs, it can also increase the vitality of your skin and promote the metabolism in skin cells. It is also helpful for relieving certain skin conditions. Additionally, due to silk’s unique absorbency and breathability, it is also good for regulating body temperature and moisture. Medical researchers carried out a study where 30 patients suffering from pruritis were given different items of clothing to wear that were made from pure silk. The results showed that those who only used pure silk products experienced greater improvement in their symptoms and did not need to use any medical creams for treatment. Patients who have developed bedsores after being bedridden for a long time have been shown to have the affected areas kept healthier and their wounds heal faster when they are given pure silk cushions and underwear, and the wounds are dressed using silk bandages. The silk helps to improve the moisture level of the skin and promote evaporation.