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To sleep, perchance on foam

Advances in polyurethane chemistry are helping revolutionize the bedding industry

by Michael McCoy
July 17, 2017 | A version of this story appeared in Volume 95, Issue 29

A blue Nuvanna foam mattress sits in a well-lit bedroom with a comforter and knit blanket on top.
Credit: Nuvanna
Nuvanna is one of several companies offering polyurethane foam mattresses in a box.

Earlier this year, new entrepreneur Alvaro Vaselli launched a company called Nuvanna that sells premium foam mattresses and other sleep products over the internet.

Vaselli is marketing his new mattress as a starting point for people seeking better balance in their lives. But as a former chemical and bedding industry executive, he knows that marketing needs to be backed up—in this case with polyurethane chemistry.

It wasn’t long ago that foam mattresses were low-end products found in discount stores and cheap motels. That started to change in the 1980s, when the National Aeronautics & Space Administration released intellectual property related to viscoelastic polyurethane foam, more commonly known as memory foam.

The Tempur-Pedic Swedish Mattress, which was launched in the early 1990s, is considered the first commercial mattress to be made from memory foam. It continues to be sold today at high-end bedding stores.

A second seminal moment in the history of memory foam bedding occurred in 2003, when Sleep Innovations debuted the first “bed in a box.” Unusual at the time, it was a mattress, compressed and packaged in a cardboard container, that expands when opened by the consumer at home.

Pricey, the new mattresses were niche products for many years, but costs slowly came down, explains Will Koonce, North American R&D director for Dow Chemical’s polyurethanes business, a major provider of foam ingredients. “We in the chemical industry did what we do best,” he says. “We figured out how to do it efficiently and at a large scale.”

A micrograph showing increasingly open cell structures of polyurethane foams.
Credit: Dow Chemical
Advances in opening the cell structure of polyurethane foams have allowed for higher air flow, enabling cooler sleep. From left to right, the images show memory foam made with Dow’s technology from before 2010, from 2010, and from 2016.

Today, aided by online sales, mattresses using polyurethane foam are a fast-growing segment of the bedding industry. Doug Todd, North American marketing director at Dow Polyurethanes, estimates that about one-third of mattresses sold in North America are made out of foam or are a hybrid of foam and traditional innersprings.

Moreover, Todd figures that sales of foam mattresses are growing at least twice as quickly as sales of traditional mattresses. And thanks to both continued polyurethane innovation and the rise of online bed-in-a-box purveyors such as Nuvanna and Casper, sales should continue to grow smartly.

Polyurethanes are produced by reacting an isocyanate—generally methylene diphenyl diisocyanate or toluene diisocyanate—with polyols in the presence of a catalyst and other additives. Carbon dioxide formed during the reaction is combined with other gases to create the tiny foam bubbles.

Unlike the bouncy polyurethane foams of earlier mattresses, memory foams have little spring. Instead, they mold to and retain the shape of a sleeper’s body—hence the term memory—and return to their original shape only gradually. Advocates say the effect can relieve tension and prevent pressure sores.

The memory effect can be achieved two ways, Koonce explains. One is basically pneumatic: By controlling surfactant and catalyst levels, mattress manufacturers can produce partially open foam cells that slowly let air in and out.

More commonly, though, memory foams are created by playing with the viscoelastic polymer structure, according to Koonce. By choosing the right polyols and catalysts, manufacturers control glass transition and hydrogen bonding effects in the soft phase of the polyurethane.

“Polyurethane is a polymeric spring,” Koonce says. “Memory foam is counterintuitive. We intentionally make the polymer a poor spring with slow recovery by changing the microstructure with different polyols.”

Early memory foam mattresses had a relatively closed cell structure that didn’t allow air to flow freely, creating what is known in the trade as an unfavorable microclimate around the body. Customers who bought the mattresses often complained that they got hot during the night. The solution, Koonce says, was to improve airflow by opening cell structure.

In a first round of improvement, which occurred around 2010, researchers played with polyol molecular weight, functionality, reactivity, and backbone to create a more open foam structure. According to Koonce, airflow increased to about 0.09 m3/minute from 0.03 m3 in the first-generation foams.

But the perception that people “sleep hot” on memory foam persisted, so last year Dow came out with what it calls “ultra high airflow and moisture-wicking memory foam technology.”

This time, Koonce says, Dow combined its customized polyols with new additives at low levels to create a polyurethane, called Vora Zzz, with even more openings in its cell structure. “The newest technology has all the windows open,” he says.

Dow claims that airflow is up to almost 0.3 m3/minute. The moisture-wicking capability of the new foam is improved as well, the company says.

As polyurethane raw material suppliers such as Dow help improve airflow, foam formulators are pulling other levers—including additives such as graphite and phase-change materials—to dispel the “sleep hot” reputation of memory foam and otherwise improve the experience of mattress customers.

All these technologies are in play in the labs and factories of Innocor, a New Jersey-based firm that calls itself the second-largest U.S. producer of polyurethane foam products. The company, which produces and markets the Sleep Innovations mattress line, operates 22 plants and distribution centers in the U.S. plus an R&D lab in Baldwyn, Miss.

Much is expected of a polyurethane bed in a box, notes Jeff Hansbro, vice president of product development at Innocor. It is assembled in a factory out of single or multiple foam slabs, covered in fabric, compressed by as much as 90%, rolled up, boxed, and warehoused for as long as three months. It is subject to temperatures that can range from 32 °C in the factory to 10 °C during storage or shipping in cold climates.

Customers who buy and open a boxed mattress expect it to regain its shape and be ready for sleep that evening. Mattresses that disappoint are routinely sent back. “One-hundred-day, money-back guarantees have become table stakes in the industry,” Hansbro says. “The unpacking experience for a customer is extremely important.”

Seeking to keep customers happy, Innocor’s researchers and engineers have made multiple advances in foam production technology since the firm launched the first bed in a box in 2003. Innocor spent the early years lowering the foam’s density, opening its cell structure, and making it more affordable. New polyether polyols from Dow and other chemical companies were a big part of the change, Hansbro says.

In 2010, Innocor introduced polymer gel beads to “act as a thermal conductivity control within the memory foam matrix” and pull heat away from the body, Hansbro says. Subsequently, the company introduced foams and mattresses with added graphite or phase-change materials to even better manage heat.

Innocor’s latest technology is called Evencor. Enabled by specialty polyols, new additives, and formulation adjustments, Evencor foams are intended for mattresses that deliver a comfortable, uniform feel across a wide temperature and humidity range.

Evencor, Vora Zzz, and other technologies are all at the ready for companies seeking to enter the bed-in-a-box business. Many just a few years old, such firms already command as much as 13% of the mattress market, according to Vaselli, the Nuvanna founder.

They’re also attracting attention. In June, the prominent bed-in-a-box maker Casper raised $170 million in a venture capital funding round led by the retail giant Target.

It’s an increasingly crowded space, but Vaselli says he knows what he’s getting into. Over the course of his career he’s worked for Dow, Arco Chemical, the foam fabricator FXI (formerly Foamex), and companies in the retail mattress industry. “I’ve experienced the entire supply chain,” he says.

To crack the market, Vaselli is drawing on a personal story of transformation from workaholic to better-balanced person. He’s also calling on his industry experience to build what he says is a better mattress out of three distinct layers of foam.

On top is a high-density, non-memory-foam “ascension” layer infused with a phase-change gel to maximize coolness. In the middle, or core, is a memory foam “equilibrium” layer intended to offer support and minimize motion transfer. On the bottom is a non-memory-foam “support” layer designed to underpin the other layers and minimize the sinking feeling that all-memory-foam mattresses can bring.

While designing the new mattress, Vaselli was mindful of the consumer’s unpacking experience. He recalls an earlier foray into bed in the box by Walmart, which sold mattresses that took two or three days to decompress. “Because of the quality of the foams today, customers can sleep on our bed the same night,” he says.

There’s more to Nuvanna than polyurethane foam, but Vaselli is willing to give the material some credit for his success so far. “Twenty years ago when I started, foam was bad and innersprings were good,” he says. “There’s been a lot of improvement in the foam industry.”


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