Foam for the Future

posted on 8th October 2019
Foam for the Future

The UK’s Zotefoams produces a range of high-tech foam materials for industrial application. Its remarkable ZOTEK F product is already used in aerospace, but now the company is exploring the wider potential for its application in executive and VIP aircraft cabins, as James Bridges, Director of HPP Products at Zotefoams, explains

While new materials frequently make their way into executive and VIP aircraft cabins, they’re often finishes for cabinets or floors, or seat and divan coverings. The stringent fire, smoke and toxicity requirements that necessarily regulate the industry mean the basic materials of cabin structure, seat carcass, wall panels and ducts, generally change little.

For those very good reasons, plus the long lead times for entering new systems and, indeed, entire aircraft into service, the industry tends to walk a difficult line between high-tech advance and conservatism. But then there are those rare occasions when something so different comes along it has the power to stop the industry in its tracks, through a step change in possibilities.

Croydon, UK-based Zotefoams appears to have just such a product. It’s foam with mind-blowing capabilities. And it really has to be handled to be believed. Holding a confusingly lightweight, embossed, beautifully coloured seat panel in the hand, twisting it to the limit of one’s strength, then watching as it springs perfectly back into shape baffles as much as it delights. The possibilities of Zotefoams’ technology are really beyond words, but James Bridges, Director of High-Performance Plastics (HPP) Products at the company, gives it a try.

A producer of closed-cell polyethylene (PE), polyvinylidene difluoride (PVDF) and nylon polyamide (PA) foams for demanding industrial applications, Zotefoams realised that the unique properties of PVDF foams provide a sophisticated, lightweight, fire resistant solution for aviation interior technology, reducing weight while exceeding industry standards.

Founded as a manufacturer of expanded rubber products in the 1920s, Zotefoams forerunner supplied aviation-grade foamed rubber from the 1930s. During the 1970s, the portfolio became polyolefin-based, since the future lay in the more specialised and sophisticated properties afforded by plastics. During the 1990s, Zotefoams investigated and developed a range of high-performance foams produced from engineering polymers.

Key to the performance and success of these foams is a unique manufacturing process using only pure nitrogen for expansion. It’s inherently environmentally-friendly and certainly far more so than the widespread method of expanding foams chemically. Nitrogen is also chemically inert, an important factor where flame retardance is a critical requirement.

Manufacture is through a three-stage process, including a high-pressure dose of pure nitrogen. The nitrogen-charged slabs of newly-produced material are loaded into a low-pressure autoclave and heated above their softening temperature, allowing controlled expansion of the nitrogen and uniform physical foaming. Most foams are chemically blown, the plastic heated and mixed with a blowing agent to produce expansion. This is more difficult to control than physical expansion and can result in non-uniform density and product properties that vary with direction. The chemical blowing agent is also released over time, producing odour and potential fogging.

Among Zotefoams’ most successful products, ZOTEK F offers a host of beneficial characteristics for aviation interior technology. A PVDF foam, it’s an inherently flame-retardant material that releases very little heat and only small quantities of smoke on combustion. Nitrogen expansion ensures it has a uniform cell structure, for the same properties in all directions.

ZOTEK F’s physical performance means it is compatible with a wide range of forming methods, allowing the production of complex shapes for applications requiring high durability. The material has become increasingly popular as carpet underlay for example, its closed cell structure ensuring high thermal and acoustic insulation values, excellent resistance to impact and long-term durability to crush. Since it’s a closed cell foam, ZOTEK F does not absorb water; as an underlay, it doesn’t collect water that might otherwise cause corrosion.

Used this way, ZOTEK F also offers huge weight savings; as much as 1.25kg/m2. Putting this into perspective, Zotefoams’ data suggests a 100kg weight reduction is the equivalent of a US$25 million saving in fuel costs over the life of an aircraft. For a twin-aisle business jet, the weight saving could be as much as 200kg.

Lighter, Quieter Air

Moreover, many aviation OEMs have adopted ZOTEK F for environmental control system (ECS) ducting, thanks in part to its light weight, but also for its noise attenuating and cost saving benefits. ZOTEK F ducts are installed as finished components, integrating the pipe and insulation functions, and reducing the need for multiple materials. Modular ZOTEK F duct systems are now available for VIP aircraft, simplifying and expediting the modification process, as well as for system upgrades on older aircraft.

ZOTEK F is also the only foam compatible with bake moulding, an increasingly popular manufacturing method for components requiring high durability. These include armrests; features such as grooves can easily be added to accommodate stitch lines for a high-quality seam.

Zotefoams already works closely with MGR Foamtex, Europe’s leading manufacturer of advanced passenger upholstery systems for premium cabin seating. The company provides innovative designs to airlines and manufacturers, among them the world’s first easily removable padded vertical surface covering, known as MGRSoftWall; ZOTEK F is the material of choice in the soft-touch SoftWall trim panels. Installed on the seat shells in business and first-class seating areas, the panels are trimmed with the airline’s chosen fabric, enhancing the luxury customer experience through soft finish and noise reduction. Individual panels are very easily removed and replaced, helping airlines keep cabins looking fresh and new, and potentially simplifying rebranding efforts.

Compared with other foams, PVDF offers excellent chemical resistance, even to aviation fluids and chemicals; it’s also biologically inert, making it resistant to mould and bacteria. With no flammable agents added during manufacture, ZOTEK F is inherently non-flammable, so it naturally achieves aviation flammability standards, including those established by the major OEMs, meeting BMS 8-371D and AIMS04-14-009 thanks to its low heat release performance and fire, smoke and toxicity properties. Since it adds very little to the overall combustibility of soft-touch interior fittings, ZOTEK F also allows a wider variety of materials to be employed.

ZOTEK F offers a range of irresistible features is an almost blank canvas for executive and VIP cabin designers to explore. Uniquely capable, it is perfectly suited to a spectrum of obvious cabin applications, but at the same time offers potential for functionality and design yet to be realised.