I have a complicated relationship with Polyurethanes. While it's true that they are the only viable alternative to vinyl (other than leather, which frequently prices itself out of the running), it is far from the miracle textile that it is often described to be. As a retail design firm, making sure the fabric we specify holds up against abuse is our top priority. Some abuse is unintentional, like denim dye rubbing off on a white vinyl or studs on a pair of jeans scratching a seat, but some is simply the result of people being stupid. Either way, it's our responsibility to do what we can to protect the furniture and make it as indestructible as possible. This means that 99% of our upholstery specifications are high performance textiles. Since the majority of our clients don't have the budget for leather, vinyl has been the industry standard for a very, very long time unfortunately.
But what about polyurethanes? When first introduced, they were described to me as "vinyl, but much better for the environment" which sounds dreamy. As our industry responds to the mandate of sustainability, more and more textile manufacturers are phasing out vinyls and replacing them with polyurethane lookalikes. Some have eliminated vinyl from their line completely. In theory, this sounds a good thing, because what is good for the earth is also good for us, right? With a long list of benefits, it seems like the swap from toxic vinyl to something new would be a no brainer.
Except none of our clients will go near it. From dealerships to fabricators, all of my attempts to specify a polyurethane in place of a vinyl have been shot down. So what on earth going on here?
What is a Polyurethane?
Before we can dive into the complications of using it, we must first understand what it actually is. In the context of interior design, the term "polyurethane" is used to describe a high performance textile that closely resembles vinyl or leather. In reality, polyurethane is actually a synthetic polymer that is used in a whole host of things like fiber glass, upholstery foam, varnishes and even adhesives. It was first discovered by Professor Otto Bayer in 1930 as a substitute for rubber, as prices were soaring during the second World War. Since then, it has been added to everything from diapers to mattresses and, as a textile, is often touted to be a more environmentally friendly alternative to PVC (Polyvinyl Chloride, aka vinyl) and a cheaper alternative to leather.
To make a polyurethane textile, a fabric backing (typically cotton) is coated with the polymer resin in its liquid state. This forms a base that is then whipped into a frenzy (technical term) and treated to ensure durability and strength. Finally, it is topped with the decorative surface layer (also know as the skin...ick) of the desired color. From there it can be embossed, treated with a stain resistant coating, you name it, the options are pretty endless. The final product is formed by the three layers: the fabric backing, the polymer base, and the decorative skin.
Benefits of Polyurethanes
The most notable characteristics of polyurethane textiles are it's high durability and relatively low cost. It has an extremely high abrasion and stain resistance, and can withstand the use of heavy commercial cleaners without discoloring. It is somewhat breathable (more so than vinyl, but not as much as leather), and has a quite soft hand. It can emulate leather beautifully, and there are more and more patterns and colors coming out every day.
Many sources brand polyurethane as environmentally friendly which I agree with, to a certain extent. Most of it's "benefits" exist only because it's "not as bad" as vinyl. For example:
- Technically decomposes over time, but it takes 500 years to do so. That is a sure improvement from vinyl, which never decomposes, but still. Leather only takes 50 years.
- Technically it is safer when burned, as it doesn't release as many toxic compounds as vinyl, but again, it is only good because it's "less bad."
- Polyurethane's contain a vastly lower level of Volatile Organic Compounds (VOC) than vinyl, which can improve air quality. This is actually a huge advantage.
- Depending on the manufacturer, it can by Phthalate, Lead/Heavy Metal, and BPA free.
So technically people aren't lying when they say it is more sustainable, but I do think the claim is a little misleading. I once heard it referred to as "Vegan Leather" which is completely preposterous, but a brilliant marketing strategy nonetheless. Calling polyurethane environmentally friendly is like calling Subway "healthy." Sure, it's better than McDonald's because it's not deep fried, but I doubt their actual ingredients come from that much better of a source.
So What's The Problem?
The main reason our clients and fabricators won't use polyurethane is because it is inherently more tensile than most types of fabric. This means that will puddle, or show butt marks, over time. When compared side by side, there is an extremely noticeable difference between the stretchiness of a vinyl versus a poly. While vinyls are pretty resistant when you pull on each corner, polys will completely change shape and are almost elastic. For this reason, fabricators find it much more difficult to work with and furniture is more likely to show wear over time.
In the photo below, you can see a mark where the fabric stretched and has been gathered in the middle. This is a pretty bad case of puddling. Mind you, I found this photo on a "Leather Care" site, which is much less stretchy by nature. If this is the worst case scenario for leather, you can only imagine what a poly might look like after a few years.
To solve this, the common recommendation from manufacturers is to install a higher density foam, or wrap the foam so the poly backing slides over the cushion easier. I have also heard from a few designer's that if you order 1" more on all sides, the fabricators will be able to stretch the material a little tighter when upholstering, but I have no clue if that actually works. In my experience, fabricators or dealers have taken one look at the specification and said "Nope, try again."
Other common issues to watch out for are delaminating and cracking. Delaminating is what happens when the skin or base starts to separate from the backing. I have heard that metallic finishes are more likely to do this, but I have no proof to back that up, it might just be a rumor. Cracking occurs when a poor quality textile is exposed to either too much humidity or varying temperatures. While high quality polyurethanes are known to dissipate heat quite well (so it isn't too hot or cold when you sit down), low quality polys can be broken down by something as simple as the the combination of body heat in an air conditioned room.
In most cases, the quality of the product is dependent on the resin used in the manufacturing process. The three main types of resin are:
- Polycarbonate: The only resin suitable for commercial use, it is the most expensive, but it's far and away the most resistant to heat, light, and humidity.
- Polyether: Only suitable for light commercial use, falls in a medium price range, and has an average resistance to heat, light, and humidity.
- Polyester: Not suitable for commercial use. It's low cost is matched by it's low resistance to heat, light, and humidity.
In addition to the type of resin, a fabric's Hydrolysis Resistance is one of the most important ratings to look for when specifying polyurethane. For commercial applications, a 5 Year Resistance rating is recommended at the minimum. In addition, a minimum of 40 hrs is recommended to to meet ACT standards for lightfastness.
So What Should We Do?
I think educating ourselves and our contractors is the best place to start. While polyurethanes are far from perfect, the improved environmental impact cannot be ignored, but should also not be overstated. It is important for design professionals to be aware of the realities and risks of what we specify, and know what to look for when doing so. I believe that as more polys are introduced into the market, more fabricators will learn how to work with them. Additionally, as time goes on and the industry continues to evolve, our clients will hopefully start to come around.
That being said, the best case scenario really is leather. All of the designers in my firm (including myself) are firmly in favor of spending more on quality up front, and saving on maintenance in the long run. This topic really deserves it's own post, but I think it's still important to mention here. In regards to high performance upholstery, leather is the gold standard. Complications exist in the tanning process and the chemicals that are used for it, but I would argue that it is the most environmentally conscious option as well. Controversial, I know! Yes, it is an animal product, but it's important to remember that no cows are being slaughtered for their hides, they are being slaughtered for their meat (which is a different conversation entirely). Apart from the fact that animal hides have been used by humans since the dawn of time, it is silly to think that manufacturing a new plastic material is better for the environment than using a resource this is readily available. Especially when you consider that it is more biodegradable and will need to be replaced far less frequently than any lookalike. Why would you waste a better product that exists anyway (as a byproduct of the meat industry) in favor of a completely synthetic product that doesn't occur naturally in nature in any form?
But I digress. The biggest challenge of leather is the cost, which is why alternatives have risen to such heights in the retail/hospitality industry. It's cheap, and it works (just not as well). While polyurethanes have a ways to go before our clients will use them, I won't be giving up any time soon. It is my hope that by educating myself and others, we can address these problems practically and move towards a more sustainable solution.