Carpet Fiber Update - March 2011

By Darius Helm


The synthetic carpet fiber industry is in the midst of its most significant transformation in decades, including a dramatic reshuffling of the ranks, due to the impact of a handful of factors. At the top of the list is cost—the relative cost of the different fibers, both short-term and long-term—along with the shift from staple yarn to continuous filament, new carpet constructions, new fiber treatment chemistries, vertical integration of mills, consumer trends, and demand for sustainable products.

Nylon is still the dominant fiber, though its share of the market has retreated to where it stood ten years ago at about 55%. But that’s where the similarities end. Over the last decade, new technologies and relentlessly rising raw material prices have played out the battle between performance and profit, entirely reshaping the landscape of the carpet fiber industry.

Marketshare Overview
One of the most fundamental changes in the fiber industry is arguably the shift from staple fiber to BCF (bulk continuous filament) fiber, a shift that had been taking place for well over a decade before it suddenly accelerated. Back in 2000, staple nylon, which was already losing share, accounted for 33% of all nylon carpet fiber consumption, and last year it ended up at less than 4%. Polyester (PET) had a 7% share back then and it was largely staple, compared to 24% today and most of that is filament. Polypropylene, which has always been predominantly filament, was at 37% and still gaining share in 2000, but last year it was down to 17%.

In the midst of this transition from staple to filament, in 2005 nylon’s trajectory was significantly altered with Shaw’s acquisition of Honeywell’s fiber business. Four years later, Mohawk bought Solutia’s Wear-Dated brand, and the rest of Solutia’s business was organized into a new entity, Ascend. That has left one major independent fiber supplier, Invista (Stainmaster and Antron), along with Universal, Aquafil, Ascend, Nylene and a handful of smaller players.

Since 2005, nylon BCF’s share has gone up about 13%, while nylon staple’s share has fallen 87%—it’s on the endangered fibers list—and nylon’s total share is down from 62% to 55%. However, over the same time period total synthetic fiber volume fell from 1.62 million metric tons to just over one million tons, according to PCI Fibres’ Alistair Carmichael, which means that nylon volume has gone from a million tons to about 560,000 tons. Over the same period of time, polypropylene’s share has dropped 30%.

The big gainer has been polyester, with marketshare nearly doubling. Polyester staple has fallen by more than a quarter, while polyester filament is up more than fivefold. And triexta (PTT), which barely registered back then, now stands at 4% marketshare (see chart on page 66 of the March 2011 issue of Floor Focus Magazine).


Each fiber type has its own distinct environmental attributes or potentials. Other than polypropylene, that is, which has no bio-based or recycled content and is also not recyclable back into fiber. However, a case could be made for calling its shrinking share a movement toward sustainability.

Polyester's main green story is its recycled content. Staple fiber can be made out of 100% post-consumer content from bottles, while the more popular filament fiber can accommodate about 25% post-consumer content. That number should rise steadily over the next few years. Mohawk is one of the biggest recyclers of plastic bottles in the world. Beaulieu also uses a lot of bottles, in face fiber for its residential fibers and in backing on the commercial side.

Shaw's joint venture with DAK Americas is another major PET bottle recycler, and the second phase of expansion will take capacity from 160 million pounds to 280 million pounds, making it the largest recycler of bottles in the nation. Also, the newer process enables the facility to avoid an additional remelt phase (which degrades the polymer) and go straight from flake to BCF, and it also yields a better blend ratio than its competitors can currently attain.

Triexta's environmental claim to fame is that DuPont makes it with 37% bio-based content, currently derived from corn through Tate & Lyle. A fermentation of the corn releases the sugars, which are used to create bio-PDO, one of the two major components of the Sorona polymer. Sorona is a true polymer, and the use of corn does not make it biodegradable--it will perform exactly the same as triexta made from petroleum based PDO.

Nylon 6 can be remelted, like all thermoplastics, but the major recycling operations currently focus on depolymerization, which reduces nylon 6 to caprolactam, then repolymerizes it into new nylon. Shaw's Evergreen facility in Augusta, Georgia is the volume recycler, and now Aquafil is in the game. The Italian firm, which has domestic operations in Cartersville, Georgia, recently opened a depolymerization facility in Slovenia, where it has existing facilities. The firm's Econyl fiber will initially feature 25% post-consumer content. Most of that content comes from carpet, followed by fishing net and fabrics. Aquafil's biggest source for post-consumer carpet fiber is the U.S.

Nylon 6,6 can't be depolymerized like nylon 6, but it's still a sturdy thermoplastic that can be remelted, and that's exactly what Universal Fibers has been doing in a partnership with InterfaceFlor for more than three years. Depending on the color, post-consumer content can go as high as 17%.

Invista, which makes nylon 6,6, also has progressive programs, but much of its focus is on its fiber's untold green story--its lifecycle advantages. The firm has put a lot of effort into comparative studies that reveal not just nylon 6,6's environmental attributes, but the attributes of Invista fibers in particular. For instance, the firm has a marketing claim that its residential Stainmaster carpet lasts up to 50% longer and stays up to 30% cleaner than other carpets. The firm also has similar, if not slightly more impressive, claims for its commercial Antron fiber. The overall conclusion is that Invista fibers have an inherently lower environmental footprint than competing fibers because of lower maintenance costs and an extended life.

Staple’s Demise
The technique for creating staple fiber is modeled on how natural materials like wool are made into fiber. The spinning process twists and braids the short, irregular fibers into a strong yarn. On the other hand, a bulk continuous filament is a single, solid fiber. DuPont invented continuous nylon filament 50 years ago, melting the polymer at high temperatures and forcing it under pressure through a spinnaret, yielding threads that were then crimped to add bulk and wound up into yarn. Then it’s twisted and heatset.

The process for creating filament, be it nylon or polyester, is cheaper than the staple process because it contains fewer steps and less labor, so it’s always been a better cost equation. However, staple has historically had the advantage of taking dye uniformly, while filament yarns were streaky. 

On the nylon side, that advantage helped slow the shift from staple to filament, a shift driven by increases in raw material costs, but starting around 2004, new equipment became available that brought uniformity to dyed filament—and there went nylon staple’s advantage. A few years later, during the recession, mills looking to cut costs targeted their high labor, high cost staple operations, further accelerating the shift to filament. 

Since then, nylon staple’s share has plummeted, and most of the staple facilities have been shut down. Last April, with volume down to about 20 million pounds (9,000 tons), Shaw shut down its Tifton, Georgia spun yarn facility. 

Even before nylon staple’s collapse, it only accounted for a quarter of all nylon carpet fiber, and it had already been losing share to filament for years. But on the polyester side, there were some different issues. For one thing, most polyester has historically been staple. Also, there is an established channel for polyester drink bottles going into polyester fiber through firms like Mohawk and Beaulieu, and until recently that was all staple fiber, because it can be made with 100% recycled content. 

Over the last few years, as the new filament technology made its way to the polyester category, the shift from staple to filament gained momentum. The ratio went from about 80% staple/20% filament to 33% staple/67% filament in just five years. From 2009 to 2010, polyester filament grew a whopping 30%.

A lot of the staple polyester out there is still coming from Mohawk and Beaulieu because of the established demand for their 100% recycled face fiber PET carpets, but both firms now offer BCF polyester carpet, though with lower recycled content—most of the new polyester product introductions from the two firms are from PET filament. And last summer, Shaw launched Clear Path Recycling, its Fayetteville, North Carolina joint venture with DAK Americas, to turn PET drink bottles into fiber, in this case ClearTouch polyester filament with 25% post-consumer content. The target is to hit 50% post-consumer content, a goal that is more attainable now that processing and filtration technologies are increasing the purity level of reclaimed PET.

Fiber Cost Equations
Today, polyester polymer is 30% to 40% cheaper than nylon, even though it costs more to take it from polymer to yarn, bringing the final fiber costs closer. Nylon’s higher cost is largely because its ingredients are petroleum based, while PET, made from terephthalic acid and ethylene glycol, is more buffered from rising crude oil costs. There’s much more competition for nylon’s raw materials, like benzene, than for polyester’s.

Furthermore, global polyester production capacity far exceeds nylon capacity; though nylon is used in some specialty applications, like molded automotive parts, thanks to its high melting point, polyester has vastly more uses. Volume in polyester water bottles alone is four times the total of nylon fiber, and it’s also bonded to rubber in passenger vehicle tires—and it’s an important apparel fiber a well. All that translates to fewer restrictions on raw material availability; polyester producers can source PET ingredients from a larger number of sources.

PET’s cost advantage is even better over nylon 6,6 than nylon 6, and that’s because the market for adiponitrile, the key ingredient for nylon 6,6, is dominated by just three producers—Invista, Ascend and Rhodia—while the market for nylon 6 ingredients is much wider open. And the premium pricing for adiponitrile will likely keep nylon 6,6 more expensive than nylon 6.

One reason PET carpet fiber has such a strong long-term cost profile is because only a small percentage of PET production goes to carpet fiber, while nylon’s carpet fiber percentage is far higher. According to Thomas Rennie of TLR Consulting, what that means is that carpet has a much higher influence on nylon than on polyester in terms of demand, so polyester can grow in the carpet industry without having a huge impact on the overall polyester market.

Then there’s triexta (PTT), which is chemically related to PET, but with enough improved performance characteristics that two years ago the Federal Trade Commission, at the behest of Mohawk and DuPont, agreed to reclassify it from a polyester to triexta.

Right now, Mohawk is the only mill to use triexta residentially, due to an exclusive agreement with DuPont, and over the last couple of years it’s also been introduced commercially, also through Mohawk, along with a small offering from hospitality specialist Clayton Miller.

Triexta capacity is an issue. Currently, the only producer is DuPont, which makes Sorona pellets largely for carpet and apparel, with an estimated, and recently increased, capacity of about 120 million pounds. 

Triexta is priced higher than PET but somewhat lower than nylon, and it is also more buffered from rising petroleum costs than nylon. However, on the commercial side, where treatments are needed to attain the necessary performance, it comes out comparable to nylon.

Polypropylene, which is used in residential carpet but more heavily in rugs, has been losing share in the carpet market at a good clip, largely because overall demand for the olefin has increased in recent years (outside of the carpet market), capacity has been constrained and costs have consequently risen. At the same time, the styling that favored polypropylene, like berber carpet, has become less popular. Supply is now starting to increase, but costs have already risen so much that it’s unlikely to lead to a rebound in polypropylene carpet, particularly because of better performance characteristics in the other fibers.

Fiber and Performance
There are a handful of key performance attributes for carpet fiber, the most important of which are wear resistance, stain resistance and oil repellency, which relates to soiling. Other important characteristics include dyeability, flammability and recyclability.

A key factor in wear resistance is resilience, and the consensus is that nylon is the most resilient fiber, with triexta close behind. But according to Invista, the dominant independent nylon 6,6 producer, triexta is more brittle than nylon, so triexta carpet under a constant load, like under the legs of a sofa, is more likely to suffer from breaking fiber than nylon carpet. Invista also claims that nylon 6,6 outperforms nylon 6 in terms of brittleness and resilience.

For overall durability, it looks like nylon comes in first, then triexta, then polyester, and finally polypropylene, which crushes down like no other fiber.

Nevertheless, there are a number of ways to mitigate the lack of resilience in fibers like polyester, and the most common method is to add twist to the fiber. In addition, loop pile constructions are more effective at maintaining resilience. Denser constructions and higher weight products also tend to mask the differences between nylon and polyester, even though the competition for share is, at least for now, being waged at lower face weights and price points. 

When it comes to stain resistance, PET and PTT, and even polypropylene, have inherent advantages over nylon, and that has been well exploited by polyester and triexta carpet producers to make a case against nylon. PET and PTT are acid resistant, and nearly all stains are acid-based. However, stain resistant treatments are commonplace in nylon, so that tends to level the field.

Soil repellency is a different issue, and it’s largely about how fiber reacts to oils. At one end of the spectrum is polypropylene, which by all accounts never met a lipid it didn’t love. Polyester and triexta are somewhere in the middle, attracted to oil but not undone by it. But nylon, it turns out, has little interest in oil; instead, it’s drawn to water.

PET’s solution is oil repellent treatments, like those offered by Scotchgard, though it’s not so common on entry level products because the treatments add too much cost to the equation.

One of the barriers to polyester, and possibly even triexta, in the commercial market are flammability ratings. Nylon is inherently more flame retardant than PET or PTT, so for commercial applications with a fire code, polyester has a hard time competing, and more than one industry expert claimed that triexta with a soil repellency treatment has trouble attaining the Radiant Panel Class One standard that nylon easily meets.

In regard to the long-term outlook for nylon, polyester and the other fibers, much of it depends on the outlook and confidence of consumers. If the economy rebounds and regains a level of activity like what we saw five years ago, people may be more willing to pay the upcharge for nylon, and that may slow polyester’s expansion. But if consumers end up looking back at the recession as a lesson about excess and the consumer culture resists a return to extravagance, polyester’s attractive pricing may win the day. 

Copyright 2011 Floor Focus