Modern industrial silks rarely have 100% silk products, mainly a combination of natural fibers, man-made fibers, and cellulose.
Natural fiber
The natural fiber contained in silk is mainly silk fiber, which is a continuous long fiber formed by the coagulation of the silk liquid secreted by the mature silkworm cocoon. It is also called natural silk. It is one of the earliest animal fibers used by humans, including mulberry silk and tussah. Silk, castor silk, cassava silk, etc.
Silk fiber is a natural filament fiber that has been practically used, and is made from the coagulation of silkworm slime. Silk fibers are divided into many types due to the different feeding habits of silkworms. Among them, there are mulberry silk fibers formed by eating mulberry leaves, tussah silk fibers formed by eating tussah leaves, and other wild silk fibers formed by eating cassava leaves, mulberry leaves, and castor leaves. Mulberry silk fiber and tussah silk fiber can retain the shape of filament fiber in the filament yarn formed by clustering, and other wild silk fibers can only be transformed into short fibers for textile processing. Among the filament yarns formed by bundling of mulberry silk fibers and tussah silk fibers, the filament yarns of mulberry silk fibers are important and account for most of the natural filament yarns.
Silk structure
The silkworm spit out two silks at the same time, but after solidification, they will merge to form a cocoon silk. The section of the cocoon thread resembles glasses. Each cocoon silk contains two silk fibers bonded together by sericin, called silk fibroin, that is, non-glue silk fibers. It has a cross-sectional characteristic close to a triangle, but the shape and cross-sectional area are not uniform.
Silk fibroin is also called silk fibroin fiber, which is the most used silk fiber.
Sericin wraps around the silk fibroin fiber, and its presence will have an important impact on the use, processing and product style of the fiber.
The content of sericin on each cocoon silk is not uniform, the silk that is spit out at the beginning has a low sericin content, and the silk that is spit out at the end has a sericin content**. Silk fiber has a relatively complete fibril structure, which can fully express the excellent quality of natural fiber.
