Companies tend to limit the number of mattress types they want to sell via bed-in-a-box. This is so they don't have endless product variation, Geeraert adds. "They tend to build up a mattress of different layers. Typically these have a support layer, the biggest block, on the bottom, with transition or comfort layers on top," he said. "With the lower density materials, especially if they are produced from MDI foams, there can be issues with recovery."
Bed-in-a-box mattresses need very open foams. 'Even our viscoelastic foam is open cell. As soon as it's pulled out of its cover and its vacuum it recovers very rapidly,' he said. 'Every comfort layer we try to make as open cell as possible because you have more air flow and a cooling effect. Memory foam mattresses with more closed cells heat up when you lie on them. New generation memory foams made of polyurethane do not have that.'
Eve uses a combination of visco foams and polyurethane foams, Lobkowicz said, along with some hybrid foams.
"There is always an emphasis on having good densities and open cell, at least with the top layers," he said. "There's some trade-off with density and breathability. But we mainly look for sleep climate-related properties – breathability, humidity, absorbance. And then there's rebound, and the support that can be provided in different ways by different foams. There's always a trade-off between visco, which aligns to your body but then you really sink in, and the kind of rebound support that doesn't allow you to sink in so much. We try to find the right balance."
Although he declined to say who his firm works with, Purple's Whatcott said his company sources foam from a couple of the large manufacturers.
"The big property we test for new vendors, and our current vendors with ongoing quality, is rebound," he said. "The last thing we want to do is ship out a bed-in-a-box mattress and it doesn't open correctly when it is unpacked.
"We like to get as much breathability as we can, we like to have good airflow through our foams. We work with our suppliers to make sure they cut at the right sizes and dimensions. A lot of that comes down to how they cure it, and whether they get a good, solid cure before they begin processing and ship it out to us."
Most of Latexco's PU foams are MDI based, but it also produces TDI foams, notably for global furniture giant Ikea, although bed-in-a-box mattresses are predominantly MDI.
"We focus on the comfort layers, and there you need MDI because those layers are very thin, 3–5 [centimeters]," Geeraert said. "We offer a portfolio of different combinations of hardness and densities of foam, so customers can choose" he added. "Here in Belgium, we have a small continuous line, a J-Flex from Hennecke. We can produce foam blocks the width of the mattress, and then cut out the mattresses."
Latexco also produces different densities, ranging from 35–50 kilograms per meter cubed, and with varying hardnesses. "If you want to deliver all over Europe, you have to have a big portfolio of different qualities."
In the U.S., Limer from Latexco's North American operations said the company is the only producer that pours polyurethane and latex under one roof.
"We do box pours in the U.S., which makes us very customizable," he said. "If the customer wants a tweak here, an additive there, we can do it without having to fire up a huge slabstock line. Also, it's good from an R&D perspective. We don't have to pour 50 feet of foam to find out it didn't behave how we thought it would."
The Middleton, England-bsed Vita Cellular Foams (UK) Ltd. has also been investing in the space. Nick Wood, operations director for Vita's Vitafoam unit, said the bedding market continues to be an area of active development.
"Vita is working proactively with its strategic partners to support the growth in their markets," he said. "Vita has invested significantly in new a foaming plant, Hyflo, with an aim of developing the new mattress market products of tomorrow," Wood said.
The company already is seeing the decision pay off, with several new product launches in the past 12 months.
For a number of reasons, Wood said, the majority of bed-in-a-box designs are 100 percent foam only. There is often one mattress construction per brand, so the feel of mattress has to be high quality and universally appealing. Vita, as an example, has developed a number of foams, including the ReVo brand.
The demands from the bed-in-a-box market for universally appealing comfort has driven both mattress designers, and foam suppliers to innovate. This is happening faster than the traditional market needed. Altering construction materials and methods traditionally gives different mattress properties.