textile yarns - the secret to fabric development
Did you know understanding textile yarns are the secret to understanding fabric, and creating a quality garment?
But, before we get started
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What are textile yarns?
Yarns and threads are not the same thing. Threads are for sewing and are what hold pieces of fabric together. Yarns are what make up a fabric.
By definition, yarns are groups of fibers that are twisted together to form one continuous strand. These strands can then be interlaced together to form a woven fabric or looped together to create a knit fabric.
Yarns are a textile development specialists secret weapon because they have the biggest impact on the final look of the fabric. It's where we can really get creative.
History of textile yarns
The inventions of yarn plays a crucial role in human-kinds evolution. The first yarns were made from animal fibers for ropes and nets which made hunting possible. Around this time there was also the discovery of fire and the wheel. These three discoveries helped to propel early humans into an age of modern progress.
so, what are textile yarns?
spun vs filament yarns
Yarns fall into two main groups, spun and filament.
Spun yarns are made from staple length fibers. Staple fiber are short fibers only a couple of inches long - like cotton. But, long filament fibers can also be cut up into staple length. To make a spun yarn, first, all of the fibers need to face the same direction (we will get to how that is done in a minute), mechnical twisting then holds the fibers together.
Filament yarns are made from filament fibers. A quick refresher, filament fibers are generally man-made (with the exception of silk), and have a really long fiber length. Because filament fibers are less chaotic than staple fibers, their yarns need very low amounts of twist to hold them together.
how to tell spun vs filament yarns apart
The easiest way? Untwist them! If tiny fibers come out then it's a spun yarn. If no fibers fall out it's a filament.
what if you can't untwist the yarns.
Sometimes you can't untwist a yarn because it's in a garment. So, how can you tell if the fabric has filament or staple yarns? Well, there are three categories we can look at to give us clues about how the yarn was made. They are uniformity, smoothness and luster, and strength.
In general filament textile yarns have a more uniform diameter. This makes sense, because the fibers run the full length of the yarn. So if a yarn has 20 filaments at one point it should have 20 filaments at every other point. Staple yarns are much more unpredictable and because of this have slight variations in diameter.
Smoothness and Luster
The smoother and rounder a textile yarn, the more luster or shine it will have. Staple length yarns tend to have less smoothness and luster than fillament yarns. This is because tiny bits of fibers stick out of staple length yarns creating a fuzz which is bad for shine.
But what is bad for shine, is actually a benefit while sewing garments. Sometimes filament yarns are too smooth and too shiny, and this can create seam slippage. Have you ever had a dress or top made in satin that starts to develop holes on the seams around the sewing threads? This is because the filament yarns in the fabric are actually sliding around and not stable.
Kind of like what happens to Cory in his silk pajamas and silk sheets at the end of this Boy Meets World clip. Start watching at 0:47...
Filament yarns are stronger and take more force to break. Staple length yarns tend to fray and slip apart.
Sustainable design tip!
Designing a jacket or dress that you want to really last forever? Filament yarns are perfect for linings in coats and jackets, or dress slips. Why? Because they are inherently slippery. By having a filament lining it is easier to slip in and out of clothing, and garments tend to show less wear and tear and get fewer snags.
Don't skip the step of lining your garment to save costs. In the long run it will help create a garment that is less likely to end up in a landfill.
types of filament yarns
monofilament vs. multifilament
Monofilament yarns are yarns that have only one filament fiber. Multifilament yarns are yarns that have multiple filament fibers twisted together.
Given the same fiber diameter multifilament yarns will have more movement and flexibility than a mono. Generally speaking, the more filaments in a textile yarn has the more flexible and less rigid the yarn will be.
How is this relevant to sustainable fashion? Well, lots of ways. For example, alternative cruelty-free rayon silks are an example of fabrics with multifilament yarns. I see a lot of first-time designers focusing on weave density and fabric weight when choosing an alternative silk. The real pros know to ask questions about the yarns. The more fibers, generally the higher the quality of the fabric.
Microfilament yarns are even finer than silk, and made of microfibers - we measure them in micro deniers. And, fabrics made of microfilament yarns are almost indistinguishable from silk. Seriously these fabrics are tricky. That is why it is important to have third-party verification testing, or at the very least burn test fabrics.
By blending microfibers with natural fibers we can enhance the quality of yarns and fabrics. This practice of microfiber blending creates fabrics that feel like natural fibers but with extra silky drapability.
Textile Yarn Twist
TPI, or turns-per-inch measures how much twist a yarn has. Twisting yarn is important because it is what holds all of the fibers together.
Soft-twist vs. Hard-twist
Soft-twist yarns have low TPI, generally 2-12 TPI. An example of soft-twist yarns are home knitting yarns.
Hard-twist yarns have higher TPI's, about 20-30 TPI. Higher twist yarns are stronger than lower twist yarns, but they do tend to have a few extra kinks and irregularities.
Too much twist
When a textile yarn has too much twist it creates a crimp yarn that has a pebbly effect on the fabric. These type of textiles yarns are crepe-filament or crepe twist.
An example of too much twist in a fabric is a cantaloupe effect in denim. The extra twist in the yarns creates a problem during indigo dying and the fabric ends up looking like the skin of a cantaloupe instead of smooth. When this happens the denim is defective and usually ends up being sold cheaply in local domestic markets.
But crepe fabrics are not always a mistake. Sometimes we use this to design special texture effects into fabrics.
There are two different types of twist direction in yarns. S and Z. S yarns have spirals that twist upwards towards the left creating an S pattern. And, Z yarns have spirals that twist upwards to the right creating a Z pattern.
To create a smooth fabric we generally want to stick with one type of directional yarn. If we are trying to create texture effects, then S and Z yarns can be combined.
As a rule of thumb, S yarns are much more common than Z yarns.
Fiber Quality in textile Yarns
Carded vs combed cotton yarns
Carding is done to all cotton yarns. This process cleans and untangles the fibers. The carding process aligns the fibers into a thick rope (without twist) called sliver.
For higher quality yarns the carded sliver is then combed. Combing removes short fibers. Sliver that has undergone combing has longer fibers, that are more uniform diameter, and have less dirt and impurities.
Combed yarns are not always better. For exampled carded yarns are perfect for flannel shirts and denim.
woolen and worsted wool yarns
Woolen yarns are the equivalent of cotton carded yarns, and worsted yarns are the wool equivalent of combed cotton yarns, they get the extra process to make them higher quality.
Just like cotton worsted is not always better than woolen. Woolen yarns are good for products like tweeds, while worsted yarns are best for smooth fine gaberdines.
single vs ply textile yarns
Yarns can be made up of other yarns - these are ply yarns. Ply yarns are two or more yarns twisting to form a new single yarn. So, a two-ply yarn is two single yarns twisting together to form one new yarn, and a three-ply yarn is three single yarns twisting together to form a new yarn. Two ply is the most popular type of ply yarn.
how to tell single vs ply textile yarns
Untwist them. When ply yarns untwist it creates smaller finner yarns. When a single ply yarn unravels it just falls apart into fibers.
why are ply yarns better?
Plying is only better for staple length fibers. Plying does not add any beneftits to filament yarns.
But, for staple yarns, two-ply is definitely better than single ply. But, with anything higher than two-ply there is not that much more of a benefit. Each of the yarns in a ply yarn is made of finer, more uniform fibers, which creates a better stronger more uniform yarn. And, these superior ply-yarns create fabrics with better hand feel and drape.
There are 3 ways to spin a yarn
Ring spinning is the oldest method of spinning fibers into textile yarns. It also produces the strongest yarns. The only downside is that the process is slow.
Open-end spinning is the same as rotor spinning. Open end spinning requires fewer steps than ring spun spinning, and because of this is a much quicker process, up to seven times quicker. But, when you skip steps, you also lose a bit of quality. Many people in the industry say that open-end spinning is more environmentally friendly. Well, yes if you skip processing steps, of course, there will be less energy needed in production. But, it will be lower quality and not last as long. So, is it really better for the environment in the long run?
air jet spinning
Air jet spinning pulls the yarns into an air vortex kind of like a mini tornado. It is 20 times faster than ring spinning. But, the possible size range of yarns is limited, and the quality of the yarns is very low.
blends vs mixtures
textile yarn blends
Blended yarns are made with two or more different types of fibers. Blending is done at the fiber level, and then spun into yarns. This is called an intimate blend.
Blends create better fabrics. And, can even help create more sustainable garments that last longer. For example, blending wool fiber and staple length polyester fibers will create a sweater that has all the warm and fuzzy properties of wool, but the polyester will help it retain its shape so it does not stretch out.
Another popular blend notorious in fast fashion is cotton and polyester. CVC or chief value cotton is a type of cotton and polyester intimate blend. It means that at least 51% of the fibers in the yarn are cotton.
CVC is a fashion developer's secret weapon. It feels like cotton but is cheap like polyester. And because the majority of its fibers are technically cotton, we are able to import it under cotton duties and tariffs (which are much lower than synthetic fibers).
textile yarn mixtures
A textile yarn mixture is a mix of two or more different types of yarns. Unlike blending which works at the fiber level, mixing works at the yarn level. Fabrics with yarn mixtures can create special effects like cross-dying.
So far we have thought of filament yarns as smooth and silky. But, through the process of texturing we can change those smooth shiny yarns into ones that are crimpy and dull.
Texturing can add stretch, bulk, better insulation, a softer hand feel, and more wrinkle resistance. But, fabrics made with these fibers become more fragile and are more prone to snags and damage.
Stretch makes clothes comfortable when we move. There are two main categories of stretch, they are power stretch and comfort stretch. Power stretch textile yarns are in garments like swimwear and athleisure. Power stretch yarns are necessary when fabrics require a lot of stretch and strong recovery. Comfort stretch is a little less intense. Comfort stretch is just a little bit of stretch that helps a garment move with the body. An example of comfort stretch would be the recent trend of 1% stretch in men's jeans.
Bare Elastic Yarns
This is just a single monofilament spandex or elastane fiber. Bare elastic yarns are generally in power stretch fabrics.
covered elastic yarns
Covered elastic yarns are spandex or elastane fibers that are then wrapped by another yarn to cover-up the stretch fiber. These textile yarns are very strong and offer high recovery stretch and recovery.
Core-spun yarns have stretch filament fibers that have staple length fibers spun around them. The stretch core is completely hidden and the yarn looks like whatever fiber was chosen during yarn spinning. Core-spun yarns are comfort stretch yarns and are in fabrics like denim.
Novelty yarns are textile yarns that are not uniform in width. But, these irregularities are not an accident they are actually engineered into the yarn.
Novelty yarns add pizzazz and texture to fabric. The only downside is that sometimes they can become expensive.
Here are a few types of novelty yarns - seed, nub, slub, boucle, spiral or corkscrew, and chenille.
Yarns are bought and sold by the pound. It would be crazy to try and calculate how many meters of yarn it would take to knit or weave fabric. But, we need a way to be able to tell the size of the yarns we are getting. So we use the yarn numbering system aka yarn size. Just like types or yarns, filament and staple, there are also two main types of textile yarn numbering systems - denier and yarn-count system.
Let's start out easy. The denier system measures the weight of yarn in relation to its length for filament yarns like rayon, polyester, acrylic, etc. This system is a direct system and makes logical sense, a finer and lighter yarn has a lower denier number and a thicker and heavier yarn has a higher denier. As a reference, silk is about 1 denier.
The system is also proportional, so a 10 denier rayon yarn is 1/2 the weight of a 20 denier rayon yarn. Easy so far, right?
The denier system is based on grams per 9,000 meters of yarn. So, 9,000 meters of a 1 denier yarn will weigh 1 gram. And 9,000 meters of a 2 denier yarn will weight 2 grams, and so on.
Now, let's put everything we have learned so far together. What does a yarn with a label 200-30-1/2-S mean? It means the yarn is 200 denier - with 30 filaments making up the yarn, and there is a yarn twist of 1/2 TPI in the S direction.
The yarn count system
The yarn count system for staple fiber yarns is a little more confusing and counterintuitive because it is an indirect system. For example, a 50-count yarn is twice as heavy as a 100-count yarn.
Things are about to get even more confusing.
Each type of fiber has its own indirect yarn count system.
The cotton count system
Cotton yarns and cotton blend yarns generally use the cotton count, c.c. indicates cotton count. But, cotton yarns also have another numbering system (Ne), Number English.
Next, we add in the plys. So a yarn that is 50/1 is a 50's cotton count single ply yarn. A two-ply yarn of the same size and weight would be 100/2.
Hold on, what? Remember the count system is inverse. A 100/2 yarn is essentially two 100 count yarns that have been spun together. But, because the system is inverse that would be equal to a 50's single (50/1).
Worsted wool is measured by the worsted count system - w.c. When we talk about worsted yarns they are listed in the reverse. So, a 1 ply 50 w.c. reads 1/50, and a two-ply 50 w.c. would be 2/50.
But, woolen wool uses the run system.
Linen yarns are measured in lea.
The metric yarn count system
Lastly, there is the metric yarn-count system, Nm. This numbering system expresses yarns in kilograms of weight to kilometers of length.
I know, this is all super confusing.
Tex numbering system
The Tex Number System aims to solve all this confusion. Its purpose was to replace the denier and count system with one uniform system. The system is similar to the denier system, in that it is a direct system. And uses easier numbers for calculations - 1,000 meters per gram instead of 9,000. So, a 10 denier yarn is 1 tex.
The system has been slow to adopt and is currently only applicable to sewing threads.
Sewing threads are not textile yarns. They are a special kind of yarn specifically for sewing machines. Sewing threads need to be strong and resilient to not break during sewing processes.
Just like textile yarns, sewing threads can be spun, filament, or core-spun and are made from fibers like rayon, cotton, nylon, and polyester.
So what makes a sewing thread different than a textile yarn? Sewing threads always have plys for extra strength, and they have higher twist, again, for more strength. Sewing threads often have finishes and lubricants that make them slippery so they don't get stuck in sewing machines.
Choosing a sewing thread
If the sewing thread is too weak for the seam, the seam will burst when someone wears the garment. But, if it is too strong the fabric will rip. Seams are much easier to fix than fabric. So if longevity of a garment is your goal, you will want the seam and not the fabric to rip first under tension.
Most industry experts agree that 60 percent is the sweet spot. When designing a garment the seams should be about 40% weaker than the fabric. This ensures the seams are strong enough to not fall apart, but protects the fabric from ripping under pressure.