Cotton and polyester are two of the most common fabrics used in screen printing.
Cotton, made from plants, is a ubiquitous raw material for clothing. Odds are good that you’re wearing something made from cotton right now.
Polyester is a broad range of manmade materials, mostly made from petroleum products, that are generated through chemical processes then made into long strands of material and woven together. Polyester is also extremely common.
We’ll cover the background of each material, the differences between them, the pros and cons, and even tell you which is better for screen printing.
Background: cotton in the clothing industry
Cotton has a long and storied history in the clothing industry, as well as in the history of the United States. Cotton has been used by humans for clothing since pre-historic times, with remains of cotton clothing found at archaeological sites dating back to 5000 B.C. and earlier.
Cotton fabrics became a mainstream during the Renaissance and Enlightenment periods in Europe, leading to a large export trade from India. This led to the East India Company in 1600. Cotton was the impetus for much of international trade during this period, which led to a global boom in trading and the maturation of cotton as a common fabric.
Cotton and slavery, however, are closely intertwined. Enslaved people from the West Coast of Africa were brought to the early United States to farm cotton and sugar. The rise of cotton as an industrial product was made possible only through the stolen labor of slaves.
The major breakthrough in cotton manufacturing and production was the cotton gin. Short for “cotton engine,” the cotton gin made separating cotton fibers from the seeds of the plant much easier, reducing the workload required to produce cotton by an unfathomable amount. In less than 20 years (1830-1850), cotton production increased 5x in the US.
In the present day, cotton is produced en masse in Chinese markets. A global supply chain exists for the creation of textiles, with raw materials moving from country to country. Many major garment suppliers use South American countries for their cutting, sewing, and dyeing operations due to the low cost of labor.
Common uses: cotton
You can find cotton in almost any article of clothing you purchase today. The most common cotton item is the 100% cotton t-shirt, a staple item for any screen printer.
Cotton is typically found in:
- and much, much more…
It’s even common to see cotton blends, such as the “tri-blend,” which is a t-shirt made from cotton, polyester, and rayon (another manmade fabric).
Since cotton is not a manmade material, many customers prefer cotton products to synthetic fabrics. Cotton products can be organic certified, and even certified for sustainability in manufacturing.
Background: polyester in the clothing industry
Polyester is the shorthand name for the chemical polyethylene terephthalate or “PET.” Created via a simple chemical process, polyester was first developed in the 1940s. By the 1970s, the material became ubiquitous: it was used to create plastic bottles for beverages and soon became the standard for single-serve beverages.
How can a plastic like PET become a soft garment?
The chemical process is too complicated to explain here (unless you’re an organic chemist), so we’ll break the process of creating polyester into a simplified version:
- Two compounds (ethylene glycol and terepthlatic acid) are mixed together
- The temperature is increased to 150-200 degrees Celsius and a catalyst is added
- By-products (methanol) are removed via distillation
- The temperature is increased to 270-280 degrees Celsius
- Any by-products and leftovers are removed through distillation
The final product is a raw plastic material that is broken down into smaller pieces, heated, and then extruded (or stretched) into thin fibers. These fibers can then be woven into garments and other raw materials.
The DuPont company pioneered the use of polyester garments, introducing it during the post-war era as a superior fabric to cotton. The original usage was actually for parachutes and other war-time materials while cotton was scarce! Polyesters are durable, resistant to moisture and wind, and extremely long-lived. The downside to that longevity is that polyester has an outsized environmental impact compared to cotton: polyester lasts for a very long time in the ecosystem without proper disposal.
So: the material that goes into a plastic water bottle is the same material that polyester garments use. Amazing, right?
Common uses: polyester
Polyester isn’t just used for t-shirts. Its constituent material, PET, is a type of plastic that’s used in everything from plastic bottles to trash cans to a wide array of consumer goods.
Some places you’ve seen polyester and PET materials include:
- Athletic wear (yoga pants, running shorts, socks, etc.)
- Household textiles
- Recycled plastic products
- New plastic products
Polyester is also used in tandem with cotton to create blended fabrics, which we cover later.
Because polyesters are a synthetic material, they’re known to persist in the environment for a long time. However, robust recycling programs often reclaim a significant amount of polyester waste. We discuss environmental concerns further in this article.
Why are t-shirts made from cotton?
T-shirts are made from cotton because cotton is affordable, easy to dye, sew, modify, or print on, and it’s often hypoallergenic. This makes it the ideal material for t-shirts, which are a highly processed product that involve a lot of cutting, sewing, and dyeing.
Cotton is a time-tested material for making clothing, so it’s the ideal material for t-shirts sold to mainstream customers. Its shrink rate is well understood. Customers are used to cotton garments and know how to launder them correctly. Inks used to print on cotton are extremely advanced, and can last for the life of the garment. The mills that make cotton fabrics are high-tech wonders and have been cranking out t-shirts for decades!
Cotton t-shirts are remarkably lightweight, durable, and comfortable. Thanks to cotton’s absorbent qualities, dyeing cotton is a cinch. Many cotton t-shirts last for decades. Cotton is available in any country at relatively low prices. The woven fibers have a soft and pleasurable feeling on the skin, which is why cotton is used for things like extremely soft sheets!
Additionally, organic cotton is an option for environmentally-conscious consumers. Organic cotton is produced without pesticides, genetic modification, and other ostensibly harmful farming and cultivation practices. Cotton (whether organic or not) does not persist indefinitely in the environment because cotton fibers are biodegradable over time, making cotton less likely to pollute the environment or wind up in a landfill.
Why are t-shirts made from polyester?
Polyester has numerous benefits as a clothing material: it is extremely functional, very durable, and it is affordable. It has different qualities as a t-shirt material compared to cotton, making polyester t-shirts useful for people in vocations that involve a lot of physical exertion.
Polyester has similar characteristics to cotton in many crucial areas. It feels good on your skin, is lightweight, and can be dyed. While dyeing polyester is not as easy as dyeing cotton, polyester garments are known to resist fading much longer than cotton garments do. Polyester is also affordable and available throughout the world.
Polyester has some interesting qualities as a material for a t-shirt that set it apart from cotton:
- It’s extremely wrinkle resistant. It’s not advised to iron polyester t-shirts – you may melt the fabric. You will probably never see a true wrinkle on a polyester garment.
- It holds very little moisture. This is great for athletes, because polyester is considered a “moisture wicking” material. Many skin-tight athletic pants (yoga pants, for instance) use polyester. In other words, polyester dries really quickly.
There is no “organic polyester,” and you can assume that any polyester clothing you have will last for decades. Polyester is an entirely manmade fabric and is essentially plastic, and because of that its effect on the environment is considerable. It’s believed that polyester fabric stays in the environment indefinitely, just like a plastic bottle would.
However, some French researchers have engineered bacteria to eat PET and polyester molecules, giving hope that the environmental harm of polyester garments could be mitigated in the future.
What are the main differences between cotton and polyester?
The most important difference between cotton and polyester is that cotton is a natural fiber while polyester is a manmade fiber. This has implications for production (since cotton must be farmed while polyester is made in a factory), the final product (cotton and polyester differ significantly in their qualities as fabrics), and the environment (polyester persists indefinitely, while cotton can biodegrade).
Cotton is farmed across the world and has been bred for multiple climates and conditions. It is generally regarded as a pesticide-intensive crop. However, it is still farmed traditionally and subject to the whims of the weather. Polyester is simply produced in a factory setting, using a series of chemical reactions at temperature. This means that cotton is subject to fluctuations in market conditions, so its price can rise or availability can fall (as happened in 2011, when cotton prices spiked dramatically).
Since polyester is a synthetic fabric, it is known to cause a mild allergic reaction in some people. Cotton is widely used for hypoallergenic purposes, such as in hospitals, for people with allergies, or for babies. The two fabrics differ considerably as final products: cotton is mostly used for textiles, while polyester and PET can be the fundamental building block for a wide range of petroleum-based products (such as plastic bottles, which can even be recycled into fabrics).
Environmentally, cotton and polyester are hotly debated. Which is better? That’s difficult to judge. Cotton is pesticide, water, land, and labor intensive – environmental costs which are often forgotten or discarded. Polyester, however, is synthetic and known to persist forever in the environment, causing a massive pollution problem for the entire garment industry. What’s clear is that closed-loop systems (such as SanMar’s South American facilities) are the way forward for the textile industry. These factories are “closed loops” and produce or re-capture all of the energy and water they need to make their textiles.
What are the benefits of using cotton t-shirts?
The benefits of using cotton t-shirts are many. Here’s a list:
- Easy to dye
- Easy to print on
- Easy to control shrinkage
- Come in light or heavy weights (thicker or thinner shirts)
- Respond well to discharge inks (the softest inks)
- Easy to tack (glue) for screen printing
- Liked by customers
- Extremely familiar to everyone
- Available as organic options
Cotton t-shirts are loved by screen print shops and consumers the world over.
What are the cons of using cotton t-shirts?
While we all know and love our cotton t-shirts, there are some drawbacks to them too. These include:
- Piling – small balls of fibers that appear on cotton clothes. These make it harder to print on cotton and some people really dislike them.
- Fibrillation – when a print has a patchy appearance and the actual shirt under the print can be seen. This is an undesirable effect of screen printing on cotton.
- Fibers and lint – print shops are often covered in fibers and lint from handling dozens of cotton shirts. Cotton lint is flammable and, to quote one print shop employee, “You’ll lint out your whole building.”
- Hard to source from the US – most cotton is grown and manufactured overseas. 100% cotton t-shirts made in the US are hard to come by at a price that most customers can afford.
- Lots of low-quality “mill t-shirts” – while some t-shirts are great, there are lots of super-cheap cotton t-shirts that are very low quality. This means finding a nice cotton t-shirt can be surprisingly difficult when purchasing in bulk.
- Cotton is tricky for water-based screen printing inks – because cotton is so absorbent, printing on cotton with water-based inks (which are soft and vibrant, and can feel just like the t-shirt) can be challenging due to the microclimate created in the print shop’s drying and curing unit. Water-based inks are utilized throughout the world more than plastisol inks (the most common type in the US).
So, cotton tees aren’t all sunshine and rainbows! There are some definite downsides.
What are the benefits of using polyester t-shirts?
Polyester t-shirts absolutely have their place. Here are the benefits:
- Doesn’t chafe. This makes it ideal for people like marathoners and cyclists.
- Lightweight. Ideal for physical activities.
- High “wearability.” Many find it softer and more comfortable than cotton.
- Athletes love it: it’s a staple fabric for many athletic garments.
- Moisture wicking. Polyester barely absorbs water. This is great for sweating: the shirt doesn’t get heavy and wet.
- Dyes last a long time. Polyester clothes virtually never fade.
- Hard to stain. Since it’s not absorbent, you can spill on polyester and probably not stain your clothes.
If you’re an athlete, you already love polyester! It has lots of applications that cotton simply couldn’t handle: from working in hot environments to running races.
What are the cons of using polyester t-shirts?
Polyester t-shirts aren’t for every single purpose, of course. While this miraculous synthetic fiber does have some upsides, there are downsides too. The cons of polyester t-shirts are:
- Dye migration. The dyes in polyester t-shirts are known to “migrate” through prints. This means your nice white print on a red t-shirt might turn pink as the dye in the polyester migrates out of the fibers. Mitigate this with a blocker base ink.
- Polyester is heat sensitive.
- Polyester melts easily, then burns at a fairly low temperature. Be careful around open flame and hot surfaces.
- Cheap polyester is known to turn a brown color when heat is applied.
- Tightly woven polyester shrinks significantly in size compared to less tightly woven polyester when heat is applied.
- Unpredictable shrinkage. Because the density of the woven polyester affects shrinkage, polyester shrinks at different rates in unpredictable ways.
- Holds odor. Some people claim that polyester holds odor more than other fabric, while others swear that it doesn’t. In our experience, polyester garments do have some residual odors even after washing.
Fun fact: most t-shirts that people rip off in movies and on TV (like the HULK) are actually just polyester t-shirts that have been heated to 400 degrees briefly. The heat makes the polyester fibers very weak, so the shirt is very easy to rip off.
Which is better for screen printing: cotton or polyester?
Here’s the million-dollar question: is polyester or cotton better for screen printing?
This is a simple question with a complicated answer, like so many things in screen printing.
To assess exactly which fabric is better for screen printing, you’ll have to look to the end customer’s needs. It’s not appropriate to give a group of people running a marathon a bunch of cotton t-shirts, but it probably is fine to give a school ordering graduation tees cotton t-shirts. Equally, you don’t want to give the school choir a bunch of neon-green polyester athletic tees, either!
We suggest using a process-based approach. Evaluate the following for your customer:
- Cotton: loose fit, lower activity
- Polyester: tighter fit, higher activity
- Cotton: most breathable, no wicking
- Polyester: least breathable, but most wicking
- Inks & Designs
- Cotton: plastisol, water based, discharge, acrylic – complex designs
- Polyester: plastisol (will dye migrate), water based inks, acrylic – simple designs
Cotton and polyester are both time-tested materials, and good print shops have experience printing on both materials. Most screen printers are more familiar with cotton!
Be sure to research your ink manufacturer’s recommendations for printing on different materials, test thoroughly, and always wash and dry at least one garment before sending it to the customer.
Pro tip to avoid dye migration: you can use a toaster oven set at 125 degrees for about an hour to simulate approximately 24 hours of dye migration. This lets you know if the dye in the garment will migrate without waiting 24 hours.
A third path: the tri-blend
Modern breakthroughs in textiles have enabled a third category of t-shirt fabric to emerge: blends.
This third category is simply a blend of fabrics. The most famous is the tri-blend t-shirt, which is a blend of polyester, cotton and rayon. These t-shirts are usually 50% polyester fabric, 25% ring-spun cotton fabric, and 25% rayon.
Tri-blend t-shirts are designed to take advantage of the best qualities of cotton (softness, shrinkage, familiarity, printability) and polyester (durability, wicking, non-wrinkling) together. Tri-blends have emerged as a very popular consumer category, as the shirts are very high quality. This is very much a “best of both worlds” outcome for screen printers, as tri-blends are more like printing on cotton than printing on polyester.