This 40S ring spun polyester yarn is a fine single yarn made from 100% polyester staple fiber. Sock factories use it for daily, casual and sports socks, while knitting mills turn it into lightweight knitted fabrics. Weaving mills and sewing factories also order it. We wind every lot on cones, so it goes straight onto your machines.

40S Ring Spun Polyester Yarn Specifications

Material	100% polyester staple fiber
Yarn Count	Ne 40/1 (40S)
Equivalent Count	About Nm 67.7, 133 denier or 14.8 tex
Spinning Method	Ring spun
Yarn Form	Cone yarn
Main Uses	Sock knitting, lightweight knitted fabrics, weaving, sewing applications
Fiber Properties	Durable, quick-drying, shape-retaining, mildew-resistant
Color Options	Natural white, bleached white, red, blue, green, yellow, purple, cyan, mixed colors, and custom shades by color card
Packaging	Carton packing
Lead Time	Stock orders: 1-2 days after confirmation. Custom orders: usually 3-15 days after confirmation.

How Ring Spinning Shapes This 40S Polyester Yarn

Our 40S ring spun polyester yarn is stronger than open-end yarn of the same count. It also feels softer and fuller in the hand. Open-end yarn wraps loose fibers around its outside, so it tends to feel firmer and bulkier. This gap matters most at a fine count like 40S, because a thin yarn has less fiber to carry the load during knitting.

Ring spinning does leave more long hairs on the surface than compact spinning. When a fabric needs a very clean face, compact yarn is the usual next step. Our guide on how ring, compact and open-end spinning compare covers the trade-offs in detail.

Polyester adds durability. The fiber resists wear, holds its shape and dries quickly, so socks and knits keep their fit through repeated washing. Its moisture regain is only about 0.4%, compared to 8.5% for cotton, which is why a polyester sock dries much faster than a cotton one.

Applications in Socks, Knitwear and Sewing

Socks: daily socks, sports socks and casual socks. Since 40S is a fine count, it suits lighter socks better than thick, cushioned styles.

Knitted fabrics and apparel: lightweight knitted fabrics, soft knitwear, T-shirts, activewear and casual wear.

Weaving and sewing: light woven fabrics and garment sewing applications.

Accessories and home textiles: gloves, hats, textile accessories and light home textile products.

For socks, check the count against your machine before you place a bulk order. A mismatch can pass the first sample, then show up in bulk as a heavy sole or a thick toe. We cover how to match yarn count to machine gauge in a separate article.

Our regular buyers include sock factories, knitting mills, sewing and garment factories, fabric suppliers, sportswear brands and yarn traders.

Quality Checks Before Shipment

Before each shipment, we check the count, strength, evenness and surface quality of our 40S ring spun polyester yarn. If you need the figures for your own approval, ask for the technical data sheet of the current lot. We match custom shades to your color card, and sample cones are available before you commit to bulk.

How to Get a Quote

Tell us the colors you need, the quantity per color and the end product. For socks, also include your machine gauge. We will then reply with a price and a delivery date for your order.

FAQ About 40S Ring Spun Polyester Yarn

Can I use 40S/1 polyester yarn directly as sewing thread?

Not as a finished thread. Sewing thread is usually 40/2 or 40/3, made by twisting two or three singles together. The thread mill then lubricates it so it runs cleanly through the needle. A 40S/1 single yarn works better as the base yarn for that twisting step. If you need plied yarn instead, send us the specification and we will confirm what we can supply.

Does 100% polyester yarn absorb sweat in socks?

Very little. Regular polyester fiber takes up almost no water, and it does not pull sweat through the fabric well either. When a sock must move moisture away from the foot, most buyers switch to a modified polyester or a cotton blend. Our article on hydrophilic polyester explains how wicking works inside the yarn.

Should I choose 40S or 30S ring spun polyester yarn?

Pick 40S when you want a lighter, finer fabric or a thinner sock on a fine-gauge machine. A 30S yarn is coarser, so it gives the fabric more body and suits heavier knits. If you want to compare the two, see our 30S ring spun polyester yarn for the heavier option.

What is 40S polyester yarn in denier and tex?

40S means Ne 40 in the English cotton count system. That equals about Nm 67.7, 133 denier or 14.8 tex. Ne is an indirect system, so a higher number means a finer yarn, while denier works the other way round.

Will fabric made from 40S spun polyester pill?

It can. Polyester staple fiber is strong, so loose fiber ends tend to form pills that stay on the surface instead of breaking off. Knit density, fabric structure and finishing all play a big part, especially in socks that rub inside shoes.