Foam gets technical
New foam composites respond to the call for high performance in a variety of applications.
By Barb Ernster
Traditional polyurethane foam is still favored for cushioning and other applications that require a variety of specs for their physical attributes, but foam producers are working with different resins, polyols and thermoplastics to produce a wide range of foam composites that can improve on performance requirements and expand on applications.
Aerospace and military defense industries are driving many new growth opportunities for foam producers because of their stringent requirements for fire protection and safety, as well as their need to lighten weight and reduce costs. Industrial equipment and medical industries are slowly becoming more sensitive to these benefits, and that awareness is opening the market to foam products that differentiate from standard solutions.
Polymer Technologies in Newark, Del., which manufactures foam composite products and custom molded foams for acoustical and thermal management, vibration damping and noise reduction, seized an opportunity to market a melamine foam product for aircraft interiors. Polyimide foam and fiberglass are typically used to insulate aircraft, but they are difficult to handle, costly to install and don’t hold up well over time. The melamine foam product, made by BASF in Germany, is lighter weight and easier to handle, has optimal flame, smoke and toxicity (FST) performance, and thermal insulating and acoustic properties. The Achilles heel is that it’s hydrophilic and readily absorbs water. If insulation in the aircraft interior absorbs water that naturally occurs from humidity generated by passengers condensing on the fuselage skin, it becomes heavy and unstable.
“It was the catalyst for us to attempt to convert the product from hydrophilic to hydrophobic, and we developed the patented process to do that,” says Robert Prybutok, president and CEO of Polymer Technologies.
Its product, Polydamp Hydrophobic Melamine (PHM) foam, received a Boeing specification in 2005 and is now used in all Boeing aircraft. It was introduced to regional jets and smaller aircraft, and has market opportunities in mass transit trains, buses and many other OEM industrial applications.
“There’s a regulation called Docket 90 that affects these transit buses and railcars,” says Prybutok. “The products they use must meet more stringent FR and smoke requirements than they previously did. That has transformed those industries away from urethane-type products to melamine-type products that don’t readily burn and give off toxic smoke.”
Polymer Technologies also sees great potential in the use of three-dimensional molded polyurethane foam for custom applications in marine, firefighting, and industrial equipment, as well as medical equipment, such as continuous positive airway pressure (CPAP) machinery for respiratory therapy.
“The ability to reduce noise, isolate components and create an acoustical air path in one 3D molded product saves a phenomenal amount of money for customers who can buy one product that replaces dozens of 2D products,” says Prybutok. “That’s the capability that we see growing significantly in the future: replacing 2D foam solutions with 3D solutions so the installation cost is much lower while simultaneously improving performance.”
SABIC Innovative Plastics in Pittsfield, Mass., a global supplier of engineering thermoplastics, launched into the foam market when one of its European customers decided to exit the manufacturing of polyetherimide (PEI) foam. To improve the variability experienced with the prior supply source, SABIC created a continuous manufacturing process for the new product, called Ultem® foam and commercialized it for the aerospace and defense industries. It has since found multiple new markets for the foam, which has high FST performance, acoustical and thermal insulating qualities, moisture stability, is extremely lightweight and is radar and microwave transparent. Besides aircraft interiors, applications are being developed for mass transit, medical, marine and other consumer-based industries.
The market for thermoplastic composites—foam being one of the core components—is exploding in general, not just for one application but for many, says Kim Choate, global product director for Ultem®. There is a lot of room for many new players and manufacturers to enter the thermoplastic composites market space as they will be utilized in every major industry in the future. Part of the demand is due to the ability to process a thermoplastic composite quickly and easily, get very lightweight structures, and have the ability to change the shape with heat even after prepreg or part construction. Rigid metals or thermosets cannot be changed after part construction.
Foam is one of the enablers that allows you to do that. “It has very nice options, and that’s driving the demand for the products,” says Choate. “PEI foam is very stable upon exposure to moisture. You can put a hard skin on the top and the bottom, then use the parts immediately, but with more traditional honeycomb materials you have to seal the edges to protect them from exposure to moisture. The labor costs are extremely high as you need to do this by hand. With PEI foam, you don’t have that. You can make most of the parts you need in a short time and you don’t have that finishing component. From a manufacturing cost point of view, it’s a huge cost savings.”
Life saving properties
SKYDEX Technologies in Centennial, Col., has introduced a thermoplastic urethane product that is saving lives in military combat areas. The product is used on the floors of mine-resistant vehicles to protect military personnel from blasts that occur from improvised explosive devices (IEDs). The vehicles typically have just a foam rubber or a honeycomb product on the floor.
“A vehicle is thrown into the air fast when it goes over an IED, and the floor literally comes up and crushes the legs of the troops inside. Our material has been shown to stop that from happening, by absorbing the acceleration of the floor into the leg,” says Peter Foley, chief technology officer at SKYDEX Technologies.
The idea for the product came from a former Nike employee, who wanted to expand into different applications. SKYDEX has many of the same properties as foam, but is engineered to a greater extent. Where foam relies on increasing thickness to get more cushioning, SKYDEX uses geometry, shaping the material to provide more or less absorption. It uses 30 to 50 percent less product to provide more energy absorption, and can be tuned to very specific loads. This is proving useful in many applications, from slimmed down shoulder, knee and helmet pads to high impact padding used in combat training rooms, sports facilities and on movie sets for stuntmen.
“For most of our applications, we need to compress and spring back, taking multiple hits or interactions,” says Foley. “A vehicle floor might only see one bomb, but it’s stepped on thousands of times, for example.”
Vibration dampening is another area the company is exploring, not only to protect valuable electronics or industrial equipment, but for personal protection from a phenomenon called whole body vibration that can cause migraine headaches. It is also looking at markets for mattresses, particularly for applications that see a lot of people coming and going, such as military bunkers, hospitals, hotels and prisons.
“In large institutional cases, hygienics is such a problem that our ability to be cleaned and aired out is attractive. And we’re recyclable because we’re thermoplastic. There are a huge number of mattresses that go into local landfills,” says Foley.
Decoding renewable content
As consumers pay more attention to what’s inside their products, retailers are seeking products made with renewable content without impacting performance. Minnesota-based Cargill has commercialized a soy-based polyol that replaces up to 25 percent of petroleum ingredients that go into flexible foams for furniture, bedding, carpeting and automotive seating.
Most bio-based producers were playing in the rigid foams market, but Cargill focused on flexible foam markets, as it is the largest market segment for petro polyols.
“We saw that if we wanted to differentiate ourselves and tackle a large market, we needed to be the first to crack the code in soy-based flexible foams,” says Jessica Koster, commercial manager for BiOH® polyols at Cargill.
Soy and other renewable products have, up to now, shown inconsistent performance and tend to produce odors. Cargill worked with several customers to develop the product and tackle the odor issue. Today, flexible foams account for the largest use of bio-based polyols, says Koster, and is a big step toward getting away from petroleum-based products. Some applications, like memory foam, are performing even better with the soy polyol foam, and costs are comparable to petroleum-based foams.
“We’re just scratching the surface today. This is a new chemistry, so as we develop new polyols that have unique performance benefits, or make foams that feel different or have different life spans, soy foams could be used more broadly than they are today,” says Koster.
FXI Foamex Innovations in Media, Pa., is also seeing the potential in “green” foams. The company produces two foams made with a natural oil polyol for bedding and for seating applications in vehicles. European mandates require that a certain percentage of the car has to be sustainable or recyclable, and the company wanted to be ahead of that potential in the United States. It is currently targeting the hybrid car market, but is hoping the OEM car manufacturers will pick up on it for all vehicles.
“We’re ready to go into production; the issue is once a car has been developed, it’s about two years before they redo the interior,” says FXI textile engineer Diane Murtonen. The company is testing one of the foams in vehicle seating now, and is hoping to eventually provide foam for the entire top of the vehicle.
The company is focusing its innovations on the comfort and everyday living market, addressing environmental issues for the home, transportation and technology arena. It has also developed a line of medical mattresses with a combination of foam and textile covering that is addressing the issue of pressure ulcers.
“We’re listening to our customers in what they want in their bedding, furniture, vehicles and now the medical industry,” says Murtonen. “Everybody wants their life to be simpler, easier and more comfortable.”
Today’s new foam products are answering that call.