According to different silkworm, it is divided into mulberry silkworm, tussah, cassava-silkworm, Saturnia japonica, polyphemus silkworm, giant silkworm etc. Silk from mulberry silkworm cocoon are slightly yellowish white in color and luster. It is fine, smooth, delicate in feel. It has a light and peculiar smell of animal fiber. Tussah silk is another kind. Tussah grows in oak forest in the cold northern mountain areas. It is a wild silkworm. It eats oak tree leaves. Mulberry silk is thin and soft. Mulberry silk fabrics are as thin as silkworm wings. It is also very light in weight. It is most suitable for face fabric. Tussah silk is thick, loose and stiff with porous internal fiber texture. As it is from the cold north, it has fine insulation and elasticity. Also because it is strong in rigidity, it can reinforce the quilt insulation. Therefore partial enterprises take the initiative to mix tussah silk with mulberry silk in making natural silk quilts. They also mark different silk content ratio. Therefore it is acknowledged by the silk quilt industry. Though tussah and mulberry silkworm belong to protein fiber, they are different in physical and chemical properties.
Silk fibroin in tussah is higher than that of mulberry silk. Sericin content of tussah is lower than that of mulberry silk. They also have different amino acid composition. Cross section of mulberry silk is almost regular triangle. Section of tussah is flat triangle. Anyway, both mulberry silk and tussah are key constituents of the traditional Chinese silk culture. Both are of equal importance. They have their respective advantages and disadvantages because of their different growing environments.
Key points in choosing natural silk:
1. Look at logo. Firstly see the product name, factory name and address, product execution standard and code, size, model, application material composition (fabric and wadding are marked separately), grade, net weight etc. If above are not shown, or the contents are incomplete or exaggerated, the consumers shall be very careful in purchase. Please buy the natural silk quilt with “100% mulberry silk” or “100% tussah silk”. If it is roughly identified as “100% natural silk”, then it is a fake product.
2. Look at sample. It offers a sample for each natural silk quilt. If the sample opening is below 20cm, it shows that there is something wrong with the natural silk quilt. Because if sample opening is too small, very possibly the factory uses good natural silk as sample to cheat the consumers.
3. Look at color and luster. The superior natural silk shall be yellowish creamy white. Color and luster are soft in its surface with long silk fiber. Each layer of natural silk is like a net, possibly with a little amount of cocoon shell. If you pull apart the surface natural silk, you then see flocculent and broken natural silk. They are not in blocks. Furthermore, rows of threads are sewn in the quilt, it can be sure that it is a fake silk quilt made of staple fiber.
Natural silk quality is decisive in the quality of natural silk quilt. Therefore the consumers can also identify the quality of different natural silk from the following four aspects:
The superior natural silk outlook has pearl-like color and luster. It shows yellowish creamy white. Natural silk surface has soft color and luster. It is not blackish, unsmooth. Natural silk is long in size. It has diffuse refraction to light. It is clean with very few impurity. Natural silk is tidy and orderly. The inferior silk appears poor pale because of bleaching agent and chemical treatment such as hydrogen peroxide etc. It has poor and dull color and luster, a lot of impurity. Bad silk is in disorder.
The superior natural silk feels soft, smooth, exquisite, slippery, elastic. It has no hard block. Fine natural silk is soft, thin and adhesive. Otherwise, it is a fake product. Bad natural silk feels tough. It is not flexible. It has a lot of cocoon stem, cocoon block, raw cocoon, chrysalis. We suggest another kind of examination. That is, strongly rub the wadding near the zipper for about 1 minute, then let it suck the bits of paper as tiny as rice granules. The distance roughly ranges from 0.3mm to 1mm. If it can suck the bits of paper, it shows chemical fiber. Or it mixes with a lot of chemical fiber. Purely natural silk does not produce static electricity.
The superior natural silk does not go through any kind of chemical treatment. Therefore it has a natural smell of the silkworm. Bad silk adds silicone oil and softener in order to be more bright and smooth. So the oily or fusty silk is bad silk.
If you burn natural silk, it quickly dies out. Therefore natural silk is not burnable. It produces white smoke in burning. It has scorched protein flavor of burning feather. Its ash is fragile. It can be instantly pinched into powder by hand. Chemical fiber burns with black smoke and irritating odor. Black ash is black and adhesive in hand-pinching. There is obvious different in-between them.
The superior natural silk is strongly tensile, while the inferior silk easily goes apart if you slightly pull it by hand. The stronger its tensile becomes, the more superior the natural silk quality will be. The research proves that tensile strength of special grade mulberry silk is the same as that of same diameter iron wire. The superior natural silk can quickly recover its elasticity, whereas bad silk is poor in tensile strength, elasticity recovery etc.
As natural silk quilt is made of the superior natural silk, no matter how you kick hardly, natural silk quilt does not agglomerate, whereas, bad silk agglomerates easily if you kick the quilt in sleep. At present, many manufacturers place some filaments in the quilt opening. Inside they will the quilts with staple fibers. Therefore the consumers can draw out the silk in the depth of the silk quilt. Staple fiber silk are made of silk scraps by some machines.
In addition, the consumers can apply 84 disinfectant to inspect the silk quality. As disinfectant contains hypochlorous acid and main composition of natural silk is animal protein, pour 2/3 of 84 disinfectant in a transparent glass jug, put natural silk into the jug, natural silk rapidly dissolves within 1 or 2 minutes. Cotton or chemical fiber does not dissolve at all.