Spun yarn is a kind of yarn made by gathering together a bundle of staple by spinning the spindles at a very high speed to twist the staples together to form a piece of yarn. The usual length of the staple of any kind, such as wool, ramie, or any type of synthetic fiber for spinning should be less than 7”. Cotton staple is usually between 3/8” and 2- ¼” long. Cotton staple of less than ½” long is usually not used for quilt, padding or spinning into yarn because spun yarn of such short staple will have very weak tensile strength which is not suitable for these fabrics. The quality of cotton is determined by the length of staple. Long staple means high quality and vice versa.
By quality cotton is basically divided into the following four major groups.
1. Sea Island Cotton: This is the best quality cotton in the world. It has the longest and finest staple reaching 2- ¼” which is the maximum length by nature. It is named so because this type of cotton is particularly found in South Carolina, Georgia and Florida and many islands off the coast of these states.
2. Pima Cotton : It is the name given to the cotton of the second longest staple reaching 1- 3/4”. It is grown in Peru and Egypt (also called as Peruvian and Egyptian Cotton). However, it is also grown in the south western U.S.
3. U.S Cotton : generally refers to cotton in United States other than Sea Island cotton .The staple length varies but may reach 1- ½”.
4. Asian Cotton : This cotton is grown in Asia, Japan, China, Pakistan and India. The staple length is usually not longer than 1- 1/8”
Other than the length of cotton staple which is of great importance, the thickness of it is important too because only cotton of long and fine staple to make high quality fine fabrics.
The wool thickness varies depending on the kind of wool and origin of it.
Synthetic fiber is made by machine and we can adjust the thickness usually between 0.01 mm and 0.04 mm based on our needs.
The staple length of each kind of the above mentioned cotton, can be substantially shorter than indicated.
Before spinning yarn, cotton of different staple length are sorted into groups such as:
- Cotton of all long staple length (called as fully combed cotton) are sorted for making fully combed yarn.
- Cotton of medium length staple (called as semi combed cotton) for making semi combed yarn.
- Cotton of all short staple (called as carded cotton) for making carded yarn.
Fabrics of fully combed yarn would have a smooth silky surface where as fabrics made of carded yarn would have nubs or dead cotton on the surface, which are usually less color absorbent. As a result it is coarse and not very soft. Therefore, we usually use combed yarn to make light weight fabrics such as shirting’s etc. but use carded yarn which is cheaper to make heavy fabrics such as heavy denim canvas.
Theoretically, a piece of yarn can be made of any size, usually from 4 count to 120 count or even heavier than 4 count or finer than 120 count.1 count yarn means 840 yards to weigh 1 lb. 2 count yarn means 1,680 yards (twice as long as 1 lb), and of 10 count yarn means 8400 yards (10 times as long) to weigh 1 lb and so on.
Therefore split the one count yarn into almost any number and call it yarn of that count .This is the system used to control the size of the spun yarn of 100% cotton, polyester, wool, acrylic, ramie, rayon or any mixture of them.