What is the correct meaning of 40s/2 and Tex29.5 of sewing thread?
When we describe a yarn/thread, there are 3 basic indexes/information. The first is the composition of the yarn/thread, for example, 100% cotton, 100% polyester, T/C (cotton+polyester), etc. Second is size/thickness. There are generally two systems in use, imperial and metric. For example, 40s is an imperial system, we can also write it as Ne 40, traditionally we write it as 40s, 20s, 30s, 10s, 7s in the textile industry. The third is the spinning method, such as OE (Open-end), OA (Ring spinning), Siro, slub, etc.
Let's look at two complete examples:
100% polyester 40s/2 spun thread. The composition is 100% polyester, 40s=Ne 40, the yarn thickness/size is 40s (imperial system), Tex 29.5 (metric system), /2 means 2 yarns/threads, 2 40s double twisted yarns/threads.
100% cotton OE 10s. 100% cotton --- composition, OE --- spinning method, 10s --- yarn size/thickness.
How to convert Ne to Tex? There is a formula to do it!
If the synthetic is 100% polyester or other man-made fibers, the formula is: Tex=590.5÷Ne. For example, 100% polyester 40s/2 yarn---Ne number, 590.5÷40/2=590.5÷40×2=29.5, so Ne 40s/2=Tex 29.5
If it is compounded as 100% cotton or other natural fibers, the calculation formula is: Tex=583.1÷Ne. For example, 100% cotton OE 10s---Ne number, 583.1÷10=58.3, then Ne 10=Tex 58.3
If the combination is mixed fibers, the formula is: Tex=588÷Ne. For example, 80% cotton 20% polyester T/C40s/2---Ne number, 588÷40/2=588÷40×2=29.4, so T/C Ne40s/2=Tex 29.5
Correct meaning of Tex 29.5. It means that the weight of 1000 meters of yarn/thread is 29.5g under commercial moisture regain.
