viscoelastic foam Urethanes Technology: vol. 18, no. 6: December 2001/January 2002: page 22 á © Crain Communications 2001 Viscoelastic foam : marketing hype or molecular miracle?

By Liz White, UT Contributing Editor the foam’s temperature sensitivity, “this is tics and conforms to body shape.” Most the key active property of viscoelastic flexible foams are “more lively, highly re- n the last decade, a new type of flexible foam,” Hackett added. silient and bouncy,” explained Stan foam—commonly called ‘viscoelastic’ Slow recovery is an obvious feature, Hager, research fellow in Bayer Corp.’s Ior ‘slow’ foam—has achieved a high used in marketing the material. If you sink division. Hager has been profile in the market. your hand into viscoelastic foam, it leaves working on viscoelastic foams for some Its marketing might lead you to believe an indentation which disappears only years now, with Union Carbide, Arco that this is a magic material with quite gradually (see pic). Chemical and Bayer.

amazing properties (see Tempur World “Conventional HR [high Viscoelastic foams, “become more box, below). resilience] foams are two- lively as you heat them up—they all have But for once, the dimensional (density and this to some degree or other,” Hager said. claims for the materials hardness can be varied); vis- Jacob Boelskifte, quality and develop- are not just marketing coelastic foams are four di- ment manager at Dan-Foam A/S, de- hype: as Paul Bergad, mensional, with hardness, scribed viscoelastic foam as a slow recov- managing director of density, temperature and ery, rather soft, but supportive foam, US mattress maker time effects,” said Denis which is also temperature sensitive in its Bergad Inc. explained, Hicks, slabstock technology indentation hardness. “What excited us most manager with Huntsman The low indentation hardness (IFD) of [about viscoelastic , based at these foams allows the body to sink foam] was that it had bene- Slow to recover—and Everberg in Belgium. “rather deeply” into the foam, while still fits as well as a story.” heat sensitive. Most foam experts listed maintaining the firm feel of a good quali- Anybody can promote a product well, similar key properties: “The novelty is ty resilient foam, Boelskifte said. Bergad said, but it is different when the that it has very slow recovery characteris- Viscoelastic foam is formulated to give product has major advantages over com- peting materials—as viscoelastic foams Medical benefits very rapidly, he said. have in health features (see box right). Hackett made similar points about design “Within five years, every hospital mattress of wheelchair pads. Sophisticated pressure- High damping will be made out of visco foam,” Hackett mapping techniques are used to assess the said. It has great benefit in stopping develop- “A key feature of ‘visco’ foam is that it is problem, with the same aim—of keeping the ment of bedsores, saving nurses and carers maximum pressure below a critical point. lazy or slow, with high damping. One of its a lot of hard work and time, he said. The principle for wheelchairs is the same main characteristics is very low resilience, Conventional HR foam mattresses cause as for beds—“to spread the load, to lower there is no spring in it,” said Padraig Hack- pressure on specific parts of the body— pressure at any given point,” Hackett said. ett, technical director at Irish foamer Kay- shoulder blades, buttocks, heels. Viscoelas- Hicks added that viscoelastic foams are foam Woolfson, based in Dublin. tic foam acts more like a viscous material at breathable, so they allow moisture to dissi- But by far the more important quality is these points, under the influence of heat pate, which is good for arthritic conditions from the body. So it softens and flows and for reducing skin irritation. They are also around these pressure points, Boelskifte usually medicated so that they have antibac- Foam-tastic! said. This spreads the load over a much terial properties. wider area, avoiding the pressure spikes that Other solutions to sores are generally “Visco-Elastic Memory Foam is a revolution- can cause decubitus ulcers, commonly more expensive, said Hackett, listing “ac- ary open cell space-age foam ... developed known as bed sores, he explained. tive” mechanised beds, complex air beds, for NASA in the early 60s. So unique are its Kayfoam data confirms this: compared and highly sophisticated water beds, used in properties that it continually adjusts and with regular pressure reducing mattresses, burns units. moulds to the weight and shape of your body viscoelastic foams give a far greater area of Viscoelastic foam mattresses can also be …itdramatically minimises pressure points, surface contact for a supine patient, with a used for burns units, to minimise pressure, thus reducing tossing and turning, signifi- contact area for the head, back, buttocks and Hicks said. cantly improving circulation, noticeably re- feet of 1872cm2 as opposed to 902cm2, ac- Sufferers from back and joint pain and ducing pain and discomfort associated with cording to Kayfoam literature. This reduces restless sleepers may also gain relief using disruptive sleep.“—US internet supplier Oh average pressure to around 15 mmHg from viscoelastic mattresses, the literature My Ach’n Back. (www.swedishfoam.com) nearly 30 mmHg with the regular product, claims. The foam supports the whole body, the firm says. while keeping the spine aligned (below). UT “The Future Is Here— … new space age Viscoelastic pads are technology … an extremely high density Tempur World also a bonus during visco-elastic foam which moulds to every surgery, because blood curve of the body… completely eliminates flow problems can occur localised pressure … at the hips, arms, and when patients are immo- shoulders [which] results in impaired circu- bilised, said Paul Bergad, lation and numbness, stiffness or pain. you managing director of US will experience tension-free sleep which is mattress maker Bergad vital to good health.”—Sleepyzzz, a US sup- Inc. Breakdown of tissue plier of foam products made by Knoxville- leading to ulcers can occur Tennessee based Knox Foam Corp. UT

22 URETHANES TECHNOLOGY DECEMBER 2001 / JANUARY 2002 viscoelastic foam Urethanes Technology: vol. 18, no. 6: December 2001/January 2002: page 24 á © Crain Communications 2001 a certain low resilience and hardness at Materials for VE foam gives “taller blocks, good shape and very 20¡C. If the temperature drops, the foam commercial properties,” Hicks commented, gets very hard, “like a piece of wood,” British Vita’s viscoelastic foams “use a blend adding that the fast cure of MDI systems is Hackett said. “If you want to see if a piece of polyols, one a high hydroxyl value polyol, also of benefit this is kind of typical for most suppliers,” of foam is genuinely viscoelastic, put it in The Huntsman specialist added that, “con- said Ken Hillier, chief technologist with Mid- trol of foaming needs to be very precise, we the freezer, to see if it hardens,” he com- dleton, Manchester-headquartered foam mented. “Above about 30¡C, the foam stick it on the line and optimise it for them.” maker British Vita plc. Dan-Foam uses a specially developed poly- gets softer and this temperature depen- One approach is to “try to have two phases ether polyol and TDI, and fine-tuned the in the polyol, each with a different tempera- dence is the reason the foam is used in ap- recipes with silicone stabilisers to optimise ture response; depending on how well the plications like hospital beds,” he said. processing in the early days, Boelskifte said. phases are mixed and the nature of the transi- With a standard flexible furniture foam, Foam index is normally below 100, he added. tion, you can get fast or slow change and tem- a hardness (IFD) of 20 at room tempera- Polymer systems for Dan-Foam’s Tempur ture will be the same if the temperature is perature response,” said Hicks of Huntsman. There are various routes to such polyols, materials are basically the “same raw mate- raised to 30¡C or if it is dropped to 0¡C, “a lot of know-how, but, because there are rials produced at different indexes,” which is Hackett said. For normal flexible PU many ways of doing this and there are a lot how the temperature is al- foam, across the ambient temperature of patents, it takes a lot of care to avoid in- tered, Boelskifte said. range, IFD values are not temperature-de- fringements,” Hicks explained. Dan-Foam uses very similar materials for pendent, he stressed. Foamers can use MDI (methylene moulded viscoelastic foam, with minor varia- “Typical furniture foam has, say, 65 diphenyl diisocyanate or TDI ( diiso- tions to cover higher moulding temperatures percent resilience: you drop a steel ball cyanate) Hicks added. MDI seems better and to handle high pressure mixing, Boel- bearing on it from a metre and it rebounds than TDI on the production line, he said. It skifte said. UT 65 cm,” he commented stressed, but “will always be a niche.” Both Kayfoam and Dan-Foam feel the “On a piece of slow foam it will only A lot of foam manufacturers are using next major growth area for viscoelastic rebound 2 cm,” Hackett said, since, viscoelastic foam in some shape or form, foam is domestic . “visco foam is very low resilience, it is observed Alvaro Vaselli, vice president of On the domestic side, there are a lot of dead, with no bounce.” A typical metal marketing and sales with Foamex Interna- mattresses now available “with a top 2 or sprung will give perhaps 95 cm tional. It is a unique way to differentiate 3 inches of visco foam, giving a very rebound, he added. products, he added. comfortable, lazy feel,” said Hackett. Hager said the viscoelastic foam mar- Cost will be a limiting factor in this use, Markets and marketing ket has grown considerably in the US over said Hackett, since viscoelastic foams are “Slow foam opened up a new market for the last 7 to 8 years. Tempur has raised the denser than conventional flexible foam us,” and it is big business for Kayfoam, market size by its promotion of these ma- and therefore use more material. Also, the said Hackett. But as a segment of the total terials and, “other producers have piggy- speciality polyols and surfactants are flexible foam market, viscoelastic foam is backed on this,” he added. more expensive. very small, he added. In the US, Hager said, almost all the Manufacturers typically use a 30 kg/m3 In a UK market of perhaps 50 kilo- foamers are making viscoelastic material. density foam for normal mattresses but tonnes a year, viscoelastic foam makes up Similarly in Europe, “All the major manu- visco foams are perhaps twice the weight perhaps 1000 tonnes or 2 percent, he esti- facturers are now making these materi- at 60 kg/m3 density. Some manufacturers mates. It is a growing segment, he als,” Hillier said. offer viscoelastic foam at around 85 kg/m3. 200 people, and matches Dan-Foam’s Aarup A Scandinavian first plant in size, facilities and capacity. Tempur Tempur is a major global brand in viscoelastic decided to build the US plant because it al- foam products, and has led the field in mar- ready shipped over 40 percent of its produc- keting the material, according to most com- tion to the Americas. It made sense to make mentators. Tempur viscoelastic polyurethane foam locally and avoid transporting the light foam products are made by 40-year- old Dan- but bulky material around the world. ish company Dan-Foam A/S, based in Aarup. Tempur products also sell well in the Far Originally a general-purpose flexible foam foam—and the firm has never looked back. East and Dan Foam is considering setting up maker, Dan-Foam is now totally focussed on Fagerdala’s major shareholders set up an Asian plant, although it is not close to a making products for Tempur World Inc. This Tempur World to market the products, with decision on this yet, Boelskifte said. organisation was set up in 2000 to market Dan-Foam as its manufacturing subsidiary. Dan-Foam’s 85 kg/m3 viscoelastic foam the products globally, following the high The Danish unit now focusses solely on mak- mattress tops are higher density than com- sales growth experienced in the last decade ing slabstock and moulded viscoelastic foam, petitors’ foams, Boelskifte claimed. Mechan- for Tempur products, Boelskifte said. together with the HR foam used as a base in ical properties including durability and ageing In 1989, when Dan-Foam was taken over the mattresses. are, “significantly better than competitors’ by Fagerdala World Foams, of Varmdo, Swe- Dan-Foam turns the foams into upholstery materials, typically made at 55 kg/m densi- den, it already had a recipe for viscoelastic backing, mattresses and , using its ty,” he claimed foam—as originally developed in the US at cutting and fabricating facilities. Tempur products are sold via a network of NASA (the National Aeronautics and Space Tempur World, which has all the distribu- 22 daughter companies who sell to furniture Administration). NASA had wanted a shock- tion rights to the Tempur products, had a shops, and through chiropractors and back absorbent and insulating foam for astronaut’s turnover last year of DKr 14000 million ($168 specialists, and direct to the public. suits. Slow foam has the shock-absorbency, million), said Boelskifte. Average annual The firm will design and make products but not the temperature protection, so, “was growth has been around 35 to 40 percent in for individual customers, it offers a person- not suitable” for space suits, Boelskifte said. recent years, he added. alised service, Boelskifte stressed. But Dan-Foam had not yet developed suc- Tempur World has doubled its foam pro- In moulded foam, Tempur has developed duction capacity with the completion in June the ‘Tempur inside’ concept to allow manu- cessful mass production of the foam. 2 Former Dan-Foam chemist Åge Kris- 2001 of a 40 000-m US foam production fa- facturers, of chairs and recliners for example, tiansen spent the next two years developing cility, in Duffield, Virginia. The Duffield plant to use the Tempur logo and to keep its brand a reproducible slabstock process for the (pictured above) will eventually employ over prominent, Boelskifte said. UT

24 URETHANES TECHNOLOGY DECEMBER 2001 / JANUARY 2002 viscoelastic foam Urethanes Technology: vol. 18, no. 6: December 2001/January 2002: page 25 á © Crain Communications 2001 Hillier said British Vita makes it, “in a sells products. A relatively new area for polymer, said Hillier. range from 40 to 60 kg/m3, depending on the Danish foamer is moulded foam parts While fiddling with the cell structure to which factory it is made in.” for office furniture and similar uses. leave vestigial cell walls can create simi- Viscoelastic foam is expensive—“three Hackett said another market for visco lar initial behaviour, these are not true vis- to four times the cost of regular foam,” foams may be in musical chairs—orches- coelastic materials, which need a “good said Bergad, raising the cost of the foam tral seating. This is a specialised market, open cell structure,” Hillier said. products the company supplies. using purpose-designed seats, since many But Hager said that, while viscoelastic With DanFoam’s Tempur mattresses, musicians must sit in specific ways in order foams, have open cells, “the windows are prices are competitive with those of a good to play their instruments, for example the not necessarily wide open,” and this in- quality spring mattress, Boelskifte said. cello. Orchestras travel with their own creases the viscoelastic effect a little. Other viscoelastic foam uses are in chairs, and comfort in sitting for long peri- “You can achieve a pseudo-viscoelastic prostheses and medical devices: for exam- ods in one position is also a critical factor. foam with a closed cell structure, but this ple a viscoelastic foam layer can be used Foamex is also working on energy ab- is unlikely to be viscoelastic over any use- under Plaster of Paris for setting broken sorbing foams, some of which are vis- ful time period,” Vaselli commented. bones, and in neck braces, said Hackett. coelastic materials, Vaselli said. Foamex’s A foam with a lot of closed cells can They are also finding use in trolley use of the variable pressure foaming seem ‘slow,’ because when crushed it pads in hospital accident and emergency (VPF) system, in combination with for- takes time to recov- units. Although patients are not generally mulating expertise, means it can make er, but this is just supposed to stay on the trolleys for any novel energy-absorbing products “not slowness in taking length of time, they unfortunately do in available with conventional processes or up air again, Hillier some countries. urethanes,” he added. said. Bergad uses three layers for the wheel- Energy absorbing foams are becoming Hackett agreed: chair pads, soft, firm and a lot firmer, so more widely used in automotive and “some manufactur- that there is no bottoming out of the packaging applications, and the Foamex ers do a little bit of a foam—quite a task with only a 3-inch materials “will deliver benefits at equal or cheat,” he said, by foam layer, Bergad pointed out. lower costs to existing plastics,” used in raising the number Viscoelastic cell Visco foam will find its way into seat- this field, Vaselli claimed. of closed cells, structure—Tempur ing, but it is too expensive to be used at the which can make a mass end of the market, it will only be used Real or pseudo effects? foam lazy. It is easy to pick these foams for the top end of the range, for people able There is a big debate as to what viscoelas- out, though, because it is difficult to draw and willing to pay lots of money—$800 to tic foam is, Hicks commented. air out of them, Hackett added. These feel $1400—for a sofa, Hackett said. In simple terms, the foam is viscoelas- like a lazy foam to the touch, but the tem- Dan-Foam does not sell foam, it only tic because it is made using a viscoelastic perature dependence is small, he said. glimpse of viscoelastic material... Then we The temperature dependence occurs VE foam renews Bergad started to restock the whole operation to because the glass transition temperature “Viscoelastic foam has turned our business use viscoelastic foam.” (Tg)ofthe foam has been designed to be around,” said Paul Bergad of mattress Bergad now turns over between $3.5 and in the right region—about body tempera- maker Bergad Inc. of Ford City, near Pitts- $4 million a year, and employs 50 in its pro- ture. Normal foam has too low a Tg and burgh, Pennsylvania. duction unit, plus, “another army of sales is also usually highly resilient rather than “Right now we primarily deal with vis- people,” Bergad said. highly damping. coelastic products,” he said, listing wheel- Growth has been high—exponential ac- “We’ve designed formulations to raise chair cushions, surgical pads, medical and cording to Bergad—with “this year one of the T to typically around 30°C,” said consumer mattresses, and even surgical the best to date,” he added. g pads for pets, among his firm’s products. Bergad’s 8-inch (20-cm) thick mattresses Hackett, adding that Tg is a range, not a Bergad set up the company to make consist of a 5 inch base layer of conventional single value. For pressure-relieving mat- 1 cheap foam mattresses for children’s bunks, firm HR foam. Next is a 1 ⁄2 inch layer of soft- tresses the Tg needs to be between 15¡ and inexpensive pads for furniture and similar er, less heat-sensitive viscoelastic foam and 30¡C, he said. 1 items, he said. the top 1 ⁄2 inches is a firmer, slightly more One aspect of the technology is to try to In 1993, Bergad said, “I got my first heat-sensitive viscoelastic type. UT make the Tg close to room temperature, viscoelastic foam Urethanes Technology: vol. 18, no. 6: December 2001/January 2002: page 26 á © Crain Communications 2001 and thus give slow recovery, Hager said. change with temperature, others a more The chemical suppliers and foamers “You want viscous damping, so you gradual change, Hicks of Huntsman have put, “a lot of technology develop- have to have glass relaxation over room pointed out. This is the focus of another ment into improving that,” Hager said. temperature to do this,” he added. But, debate: whether the temperature sensitivi- But Dan Foam sees the “very steep

“you don’t want to leave an impression ty should be broad or narrow. US special- Tg,” of its Tempur material as “one of the long-term, you want recovery.” ists say broader would be better. good things in a mattress application,” Broadening of the glass transition peak Current viscoelastic foams can be too Boelskifte said. “It maintains a rather reduces the temperature sensitivity, and temperature sensitive, said Hager. This rigid foam at low temperatures, then Hager said another possibility is to have means they are not suitable for auto- when the foam is heated by the body double peaks. motive seating, as they would be too hard temperature, it shapes to the body and in cold winter conditions. Also, in a non- stabilises it,” he commented. Slow, slow, quick-quick, slow heated hotel room, such mattress foam US users seem to prefer a softer feel to Some slow foams give a sudden hardness may become too hard, Hager said. their mattresses. It is a selling point in some regions for the foam to be firm, and only soften at body temperature, Vaselli said. But for the US market, Foamex, “wanted to have an initial feel which was more comfortable,” he said. People “don’t want the bed to change its feel from show- room to bedroom and over the year,” Vaselli said. In Foamex’s recent work it, “wanted to make the temperature range where the material is viscoelastic much broader,” Vaselli explained. Bergad also commented that if the user’s house is cold, the mattress can feel firmer. The ideal material has to have a controlled temperature sensitivity; users “only want to sink to a certain point,” some support is essential, he said. Soften- ing between 70¡F (21¡C) and body tem- perature (36.8¡C) is the right sort of range, Bergad said. But DanFoam’s Boelskifte pointed out that the majority of beds are used at am- bient temperature in peoples’ houses. New from Foamex Foamex International is using its newly de- veloped proprietary VPF (variable pressure foaming) processing technology, in combina- tion with internally developed formulations, to make a new line of viscoelastic foams. They are initially avail- able in two high-den- sity grades, said Al- varo Vaselli, vice pres- ident of marketing and sales with the Linwood, Pennsylva- nia, headquartered foam producer. Foamex is using a proprietary process and protected chem- istry to give benefits Alvaro Vaselli never seen before in conventional vis- coelastic foam, he claimed The flexible foam maker has been work- ing closely with some foam customers in the US on these materials, Vaselli said. It has had products available for two months now, and is just about to launch the new grades on the market, he added, in a 19 Nov telephone interview. Foamex is aiming these foams at the medical and residential bedding markets, for mattresses and . UT

26 URETHANES TECHNOLOGY DECEMBER 2001 / JANUARY 2002 techfile Urethanes Technology: vol. 18, no. 6: December 2001/January 2002: page 27 á © Crain Communications 2001 This temperature does not vary signifi- From hospital to home turers worldwide. cantly in the developed world, since the The Kaymed range is endorsed by leading advent of central heating and air condi- Kaymed viscoelastic foam is the result of a chiropractic associations and consultants, $250 000-investment in R&D by Dublin, the firm claims. tioning, he pointed out. Ireland-based foamer Kayfoam Woolfson. Kayfoam Woolfson has been in business In contrast to the US, users in the UK Far from relying on NASA, the company’s for more than 100 years and now employs want firmer support, Vita’s Hillier’s said. researchers, led by Padraig Hackett, devel- over 400 people at six manufacturing loca- “UK customers will probably be looking oped the material in response to the slow- tions—in Dublin, Cork and Kildare in Ireland, for a little harder foam than other markets ness of a PU foam toy—a ‘doughy’ nerf ball. and Manchester, UK, with smaller compo- want,” he said. These toys are, “slow” but not temperature nent-manufacturing units in South Wales Also the UK has much tighter flamma- sensitive. The research team had been ex- and Belfast. perimenting with temperature-sensitive Kaymed is also aiming at the US market bility requirements than the rest of Eu- polymers and felt if they could combine with Federal Foam Technology and other rope. “A lot of our [British Vita’s] materi- slowness and temperature sensitivity it strategic partners. al is sold into the UK market,” he added. would create an pressure-reducing materi- The firm has just launched a range of vis- “So the material has to pass the UK flam- al—offering support with a flotation effect. coelastic consumer products under the Im- mability laws as well as doing the job of Kayfoam made the first sample in Novem- pression name.The firm has used its Visco pressure relief,” he said. ber 1997, named it ’Kaymed Visco,’ and set material for some years in its own range of Irish foamer Kayfoam also makes its up its Kaymed Division that same year. King Koil beds for the UK and Irish market, “The pressure-reducing properties of the but “it has taken some time for bedding viscoelastic foam flame retardant. It Kaymed products won approval through companies to realise the potential of higher- claims to be the only company in the evaluations at ward level from carers and pa- end genuine Visco as a mattress interior,” world that makes an 85 kg/m3 density (5.5 tients alike,” according to the firm. chairman Solomon Woolfson said. pound) viscoelastic foam to the UK flame Kaymed has recently been awarded two Kayfoam Woolfson is also franchising its safety standards. major NHS contracts—from Cornwall NHS marketing approach and licensing the whole and Community Care of Northern Ireland. It process to firms capable of meeting the ex- Longevity also an issue in US has also licensed distributors and manufac- acting technical requirements. UT Bergad now has viscoelastic foam, Foamers are addressing this aspect: “poured just for us.” Previously, “we “We know that a feature of some mat- Slow to develop slow foam could not find the longevity which we tresses on the market is that they lose their The viscoelastic foam concept was devel- needed,” with foam from some of the viscoelasticity over time,” Vaselli said. So oped in the US around 25 years ago, said major suppliers, Bergad said. a key objective of Foamex has been to Vaselli. So why did it take so long to be Medical mattresses are used in the, make a foam with viscoelastic properties commercialised? “worst situation ... when someone lies on that do not deteriorate long term. One reason was that the foams are “not easy it 24/7 (24 hours a day, 7 days a week),” Hackett said the only factor he has seen to make,” said Hillier. Raw material suppli- and the material can suffer permanent set, which changes the viscoelastic nature of ers—Shell, Dow, Bayer, Huntsman—will Bergad explained. the foam is humidity. “If you raise the hu- offer formulations, but using them on a pro- Bergad’s current foams, “are holding midity to 100 percent, this affects the re- duction scale machine is not simple. up extremely well,” he said. They have silience, which also goes up, and the foam Vaselli made the same point: process- been in medical use for over five years acts more like a normal foam. Also the ing a quarter of a tonne of foam a minute now and have shown less than 2 percent temperature effect diminishes,” he said. on a commercial-scale production line is loss of height during this time, he said. quite different to making some success- fully in a laboratory. are available under the Elastoflex name, Foam index (OH to NCO ratio) is im- Varying cell morphology Schmidt said. portant: higher index foams give “better German PU systems supplier Elastogran is The system uses high molecular weight offering systems for moulded viscoelastic hydrophilic polyols and isocyanate prepoly- processing, but too high and you lose vis- foam under the Cosypur name. These have mers based on MDI, and special additives, coelasticity,” Hillier commented. adjustable cell morphology, using high mole- used to control the phase separation of the The real advance in getting these foams cular weight polyols and additives, said Peter ureas, Falke said. “To achieve a different cell into the marketplace was being able to Falke, a research chemist at BASF morphology we use a different additive,” he mass-produce them reproducibly and con- Schwarzheide GmbH. With perforated cell said. These materials are not temperature trol the performance, agreed Hager. walls, a viscoelastic foam results, while to- sensitive, this is not an issue, according to The foams have had a fairly narrow pro- tally open cells give a supersoft foam. the Elastogran specialists. UT cessing window, and machinery develop- This makes it possible for the industry to ments were a factor, said Hager, citing the make supersoft water-based foams using MDI, previously only possible with TDI, use of high-pressure machines with a nu- said Falke. cleating capability that gives highly uni- Cosypur is a very high hysteresis foam so form cell structure. Developments in com- it can absorb a lot of energy, the BASF spe- puterised control have helped by raising cialist said. It acts like a shape memory repeatability, Hager said. foam, with the perforated cell walls behav- Another factor in the slowness of the de- ing like a pump for the air in the cells. velopment may have been that viscoelastic The price of the material is comparable to foam did not represent a “sizeable market” that of conventional flexible foam systems, to the chemical suppliers, Hackett said. said Hans Schmidt, senior manager for CASE technical service with Elastogran Also, hospitals were “maybe a little GmbH, based in Olching, Germany. Examining a moulded are (l-r): slow in realising the potential of the One potential use for Cosypur is to make Peter Falke, Heinz-Jürgen Schröder foams,” Hackett feels. all-PU office seating. Rigid PU can be used of Elastogran’s CASE/flexible foams Both Kayfoam and British Vita had the for the structural parts, with Cosypur flexible unit at Schwarzheide, and Lothar added challenge of developing fire resis- foam and an integral skin PU cover. Baum, manager of the CASE/ flexible tant visco foams to sell into the stringent- Similar systems to make slabstock foam foams unit. ly regulated UK market. UT

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