sustainable denim development
A few tips when buying your next pair of eco-friendly jeans
Conscious fashion is not clear-cut, there is no end all pair of jeans that can claim these are the most sustainable jeans for women. It’s a spectrum. Instead of demanding a black and white sustainable and ethical world, the narrative needs to shift to a conversation about design, and the impacts both good and bad, of those design decisions.
You don't have to go out of your way to buy eco friendly jeans that promise to save the world. Becoming more sustainable can be as easy as committing to wearing your newest purchase at least 30 times.
During my panel at SXSW, I introduced my idea of changing the way we talk about sustainable and ethical fashion with an example of how polyester can actually make a pair of jeans more sustainable. Gasp, how could plastic poly possibly create eco friendly jeans?
Since posting the first teaser of the panel from SXSW on Sustainability and Ethics in Fashion Technology, I have received quite a few questions about how I can argue using polyester could be sustainable. I realized that there is a lot of misinformation out there about textile science and development. So, if you are interested in diving into the world of textile engineering and garment development this weeks post is for you.
the difference between stretch and structure
Stretch comes from elastane or spandex, it gives clothing comfort, and it is what allows us to move freely without limitation or restriction. Structure is achieved by using polyester, it is what gives a garment shape and it prevents bagging and sagging during prolonged wear. Polyester is extremely rigid, not stretchy.
the importance, and limitations, of stretch
When developing the perfect denim there are two testing numbers we look at, they are stretch and recovery. And, by using those two numbers together we are able to calculate a figure called growth.
In wovens, stretch and recovery comes from spandex or elastane. It is measured by how much a garment can be stretched, and then how much it can recover to its original shape. Growth is the difference between the two. By measuring growth we are able to determine performance on how quickly a fabric will lose its stretchy qualities and bag out.
During denim development, while designing textiles there are also lots of other factors to take into account like how quickly the stretch bounces back – does it slowly make its way back like silly putty, or does it spring back like a rubber band, this is called power. Generally, you want your jeans to snap back - those are going to create the best shape. Add onto that tear, tensile strength, wear, pilling, colorfastness, and other standard industry tests, and you have a lot of variables we are able to design into to make a “better” product. But, for the sake of keeping things simple for this article we are going to only focus on stretch, recovery, and structure.
These numbers in denim development are fundamental in determining if a garment will bag out at the knees and butt after one wear. I am sure anyone that has bought cheap denim before has experienced putting on a pair of perfectly fitting jeans in the morning, and by the evening the knees are all loose and wrinkly and your butt looks like you are wearing a diaper. The only solution is tossing them in the wash and drying them so they snap back to their original shape. By designing intelligently, we can prevent this from happening, so you can get more wears out of your pants.
Pants stretch out because the areas of our knees and behind are where all the movement and stretch happens, as we walk, sit, move, and go about our daily business our pants are stretching and returning back to their original shape, eventually the fabric becomes tired and can’t snap back the way it used to.
When we launder those pants the fibers and yarns become relaxed and shift back to their original form. But, the process cannot continue forever, after many cycles of stretching out and laundering eventually those pants will stay saggy and baggy.
It is a common misconception in denim development that more stretch leads to a better product, denim should never have more than 5% stretch, and ideally, 1-3% is more than enough (except in the exception of power stretch). Stretch from elastane or spandex is one of those things where less is usually more.
To date, there is no perfect elastic that stretches back every time and last’s forever, eventually, it wears out.
Spandex and elastane are also very expensive fibers. In my experience, while developing fabrics for fast fashion, stretch is usually the first place we cut costs, either by switching to a lower percentage, removing it all together, or using a lower quality fiber that does not have the same longevity as the expensive stuff.
what about 100% cotton denim?
100% cotton also stretches and bags out.
I have broken in raw denim before, and it is a tedious process. Essentially you need to buy the pants so tight that you can’t even button them. After weeks of daily wear, they will stretch to a comfortable size. But, once you wash them, well you are SOL, and need to start the whole process again.
Committed denim lovers are willing to sacrifice comfort for an authentic style like this, but most people I know that have tried to go raw and selvage end up giving up and those pants sit in their closets and end up getting tossed… seems pretty wasteful if you ask me.
structure picks up where stretch falls short
As explained above, there is no way around baggy knees when you are designing only with cotton and stretch. To mitigate the design flaws of spandex, during denim development we need to turn to materials that can provide structure, and will help the garment retain its shape when spandex becomes fatigued. This is where a bit of polyester can make all the difference.
the first uses of polyester
Historically polyester has been marketed to consumers as an easy-care fabric - easy wear, easy home launder, and it last’s forever.
One of the first mainstream uses for polyester was permanent press and wrinkle-free garments. Because, fundamentally, polyester is a plastic it can be melted to create and hold a shape. The heat inside a home drying machine is typically not hot enough to undo the engineered shape, but the reason most poly clothes have a no iron care label is that they will straight up melt under those conditions.
Don’t believe me? See for yourself. If you have an old poly garment, take a small piece and light it on fire, it will melt and turn to a puddle of molten plastic.
Today we don’t see permanent press as much in pleated pants, but instead in this trend of pleated skirts and dresses.
poly for stability in denim
Paige from Paige Denim said it best all the way back in 2014 - "If it says 70 percent cotton and 30 percent polyester blend, the jeans will hold you in like a girdle. If it's 98 percent cotton, they will stretch and sag."
By using poly, everything is held together. The poly and spandex are able to work together and compliment one another, allowing stretch for comfort and structure for long wear.
According to The Guardian, a load of laundry washed at 40C and dried on the line has a CO2e of 0.7kg. A load of laundry washed, and then tumble dried has a CO2e of 2.4kg. This means that drying alone accounts for over 70% of the eco-footprint of a load of wash. The Guardian goes on to hypothesize that if you did laundry every other day for a year, you would release as much CO2e as taking a flight from London to Glasgow, including taxi rides to and from the airports!
If we can take the same pair of cotton pants that we talked about earlier on, the pair that needs to be washed and dried every time they are worn because they stretch out, and add a bit of poly to help them keep their shape, now they only need to be washed once every 5-10 wears. Jeans made in heavyweights with well-engineered contents can last 10+ years instead of 1 season. Can it not be argued that by using poly we have created a more sustainable garment?
full product lifecycle
It is becoming a common misconception that 100% cotton garments are better when looking at the full garment lifecycle, and how our clothing is processed after we are done wearing it.
When fiber recycling first came out only garments made of one specific fiber could be broken down, blends were out of the question. But today, there are new technologies that are getting really good at breaking down, separating, and reusing blended garments. The thought that 100% fiber content garments are the best solution to post-consumer recycling is old school.
making the product even more sustainable
Just because something is designed sustainably, that does not mean there is no more room for improvement. We need to move away from the notion that there is a final stamp of sustainable and ethical approval and embrace the fact that there is always room for improvement.
using PET recycled poly instead of virgin poly
Instead of designing using virgin poly that requires new petroleum resources, we can use recycled PET poly derived from used water bottles. By opting for recycled we are repurposing waste into a new product.
accounting for microfibers
Another issue with polyester is that when we launder at home, tiny microfibers break off and are released into our oceans. It has become such a problem that "if you are eating fish then you are eating plastic". There are home laundering bags and other easy add-ons that catch the microfibers in your washing machine before they can be released into the environment. So if companies gave these bags away (they are extremely inexpensive to make) with the purchase of the jeans, the product has become, yet, even more sustainable.
there are no right answers
The point of this article isn’t to tell you to only buy polyester blend jeans. The purpose is to get you thinking. How can materials be used to create longer lasting, more sustainable products? When looking for product longevity the answer is not always the obvious one.
Textiles and clothing are much more complex than we often realize. A small change, like the TPI (twist per inch) in a yarn, can create a totally new fabric with completely different properties. Crazy right? Or, using all of the same components and changing the density of a weave or the gauge on a knitting machine we can produce something totally new. The art of textiles is playing with and combining these tiny changes to make better fabrics.
So instead of raising our pitchforks at the mention of poly, let’s start learning about it and discussing what it really means when used intelligently.
Now, you might be asking, what gives me the authority to preach this opinion that goes against much of what the sustainable community believes? I started the first 3 years of my fashion career representing Asian denim mills in the US. I worked with major labels, (check out my customer list here) to develop performance and price sensitive product, learned how to operate testing equipment and do my own testing, and spent weeks inside wash houses learning how to do every job from the science of formulating enzyme wash equations to hand sanding on a bladder. I spent this time, after receiving my degree in Textile Development and Marketing from the Fashion Institute of Technology, learning the science of the industry from fiber selection to garment fit.
This is a photo from 2012 of the first pair of jeans I ever hand sanded - taken via Blackberry (rip) - they are definitly not eco friendly jeans, but I am proud of them non the less.
If you are interested in learning more about textiles and their implications from PhD’s and textile engineers (yes it takes an engineering degree to develop blue jeans) please email us for resources and references.