Linear density and length of fibers and yarns
The linear density and length of fiber the linear density of fiber refers to the thickness of fiber. The length of a fiber is the length of the fiber.
Textile fibers must have a certain linear density and length, so that the fibers can embrace each other, and spinning yarn depends on the friction force between the fibers. Therefore, the textile fiber has a certain linear density and length, which is one of the necessary conditions for textile processing and making products have use value.
The linear density of textile fiber is closely related to the properties of yarn and fabric. In general, the lower linear density and better uniformity of fiber are beneficial to textile processing and product quality. In the influence of fiber linear density on fabric wearability, the fabric made of finer fiber is softer and has softer luster. Thinner fabric can be made from finer fiber, and garment fabric with good air permeability and silk like effect can also be made. But the fabric made of fine fiber is easy to fuzz and pilling, while the coarse fiber fabric can be made into stiff, rough and thick fabric.
Similarly, the length of textile fiber is closely related to textile and product quality. Long fiber length, good length uniformity and less short fiber content are beneficial to textile processing and product quality. Under the same conditions, if the fiber is long, the yarn strength is high, the evenness is uniform, the surface of the yarn is smooth, the fabric has good fastness, smooth appearance, and is not easy to pilling. In addition, on the premise of ensuring a certain yarn quality, the longer the fiber is, the finer the yarn can be spun, which can be used to make lighter fabrics. For those with shorter length, length is more important than linear density. For example, length is the most important indicator in cotton grading and pricing.
In textile fibers, the linear density and length of natural fibers are not uniform, and sometimes the difference is large. It varies with fiber varieties and growth conditions. The chemical fiber is manufactured artificially, and the linear density and length of the fiber can be controlled and determined in a certain range according to the requirements of fiber processing and use.
Bulky yarn bulky yarn is made of two kinds of fibers with different shrinkage, and then the yarn is treated in steam or hot air or boiling water. At this time, the fibers with high shrinkage produce larger shrinkage, which is located in the center of the yarn, while the mixed fibers with low shrinkage are squeezed on the surface of the yarn to form a ring shape due to small shrinkage, so as to get fluffy, plump and smooth yarn Elastic bulky yarn.
Core spun yarn core spun yarn is usually made of synthetic filament with good strength and elasticity as the core yarn, wrapped with short fibers such as cotton, wool and viscose fiber and twisted together. The core spun yarn has excellent properties of filament core yarn and short fiber. The more common core spun yarn is polyester cotton core spun yarn, which takes polyester filament as the core yarn and is wrapped with cotton fiber. There is also spandex core spun yarn, which is made of spandex filament as the core yarn and wrapped with other fibers. The knitted fabric or jeans material made of the core spun yarn can stretch freely and fit comfortably.
Linear density of fibers and yarns
Linear density is one of the most important physical and geometric characteristics of fiber. It not only affects the textile processing and product quality, but also is closely related to the wearability of fabric. Similarly, linear density is also the most important index of yarn. The linear density of yarn affects the physical and mechanical properties, handle and style of textiles. It is also one of the important basis for fabric design.
The linear density of fiber and yarn can be expressed in many ways, which is usually expressed by an indirect index proportional to the cross-sectional area of yarn. Commonly used indicators are tex (number), metric number, English number, Dan number, etc. In general, the linear density index of fiber and yarn is mainly divided into fixed length system and fixed weight system.
Fixed length system refers to the weight of a certain length of fiber or yarn. The larger the value is, the thicker the fiber or yarn is. At present, Tex, dtex, MTeX and D are commonly used. The legal unit of measurement in China is special number system.
Tex is referred to as "Te", which refers to the weight of 1000 meters long fiber or yarn at a given moisture regain. Tex for cotton yarn commonly known as the number.
In addition, diameter can be used to express the linear density of yarn. Yarn diameter is an important basis for fabric design and manufacturing process parameters. It can be measured under a microscope. However, in actual production, the diameter of yarn is obtained from the conversion of yarn characteristics or yarn count and yarn density.
In the representation of linear density of strands, the special number system is expressed by multiplying the single yarn number of strands by the number of strands, such as 14 × 2。 When the number of single yarn in the strand is different, it is expressed by adding the number of single yarn, such as 16 + 18. The count system is expressed by dividing the number of single yarn into the number of strands, such as 50 / 2. If the number of single yarn is different, the number of single yarn should be paralleled and crossed with diagonal, such as 24 / 48.
The linear density of multifilament of chemical fiber is expressed by the number of single filament and total tex number. For example, 16.5 tex / 30 f means the multifilament bus density is 16.5 tex and the number of single filament is 30. The linear density of the multifilament of the chemical fiber or silk is the sum of the linear densities of the monofilament.
