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June 1, 2004

5 Min Read
Melamine foam replacing polyurethane in aircraft seats

RESINS/COMPOUNDS

Melamine foam replacing polyurethane in aircraft seats

Significant weight-savings potential is causing airlines to partly replace polyurethane (PUR) in seat cushionsing with Basotect melamine resin foam from BASF. French seatmaker Groupe JSO has patented a process for combining Basotect, which it obtains in blocks and then cuts into shapes, with other foam materials.

Basotect was originally intended for applications using its good sound-insulation and fire-resistance qualities, and those that placed no direct load on its fine cellular structure. Although flexible, it cannot be used on its own in cushioning because it has poor recovery properties and tear resistance, and is made only in one hardness. JSO''s Soly''t (pronounced "so-light") is a composite cushion with a core of Basotect encapsulated in molded PUR foam. Physical properties exceed those of the standard foams used in aeronautics. Soly''t showed no signs of compression fatigue when subjected to 80,000 load cycles.

Soly''t also conforms to the aircraft industry''s tough fire safety rules, where approval is only given to cushions that can withstand a direct flame of 1000C for two minutes while retaining 90% of original mass.

Agnes Timbre-Sauniere, managing director of JSO, says Basotect''s density of less than 10 kg/cu m means that Soly''t cushioning can be made 50% lighter (70% for special comfort products) than standard PUR foam cushioning. A 555-seat Airbus A380 equipped with Soly''t seating would be 600 kg lighter than one with 100% PUR.

"One planemaker calculates that savings in fuel would recoup the cost of refitting an aircraft with Basotect cushions in just two months," says Werner Lenz, responsible for sales and marketing of Basotect in France.

The first aircraft to be completely fitted with Soly''t cushions was an Aerospatiale ATR 42-500 belonging to Air Caraibes. Cathay Pacific has since replaced the cushions in its first- and business-class seats with the cushions, and Corsair will reportedly use them in Boeing 747-400s.

Timbre-Sauniere says she can imagine applications for Basotect outside the aircraft industry. One U.S. company has a license from JSO for production of seating for trains, and other manufacturers in the U.S. already use Basotect in flame-proof mattresses. BASF, Ludwigshafen, Germany; +49 621600; www.basf.de/basotect. Groupe JSO, Toulouse, France; +33 563 310069; www.soly-t.com

Nanocomposites find new home in nylon 6

Dinalon compounds contain less than 8% by weight of clay platelets. One has a modulus greater than that of a 30% mineral-reinforced compound (4.4 vs. 3.0 GPa), but is 15% less dense. Deflection temperature under load is also higher (104C vs. 95C at 1.8 MPa). A second grade, intended as an alternative to impact-modified nylons, has a greater modulus (1.6 vs. 1.3 GPa) and lower elongation (4.65% vs. 40%), but comparable impact strength (60 vs. 90 kJ/sq m). Grupo Repol, Almazora, Spain; +34 902 292292; www.repol.com

Insulation advance could prompt increased sheet sales

Driving a technology push and simultaneously trying to prompt a market pull can be tricky business, but specialty chemicals supplier Cabot (Boston, MA; Rheinfelden, Germany) hopes to do just that with Nanogel, an aerogel that can replace insulation materials like glass, wool, polystyrene, and polyurethane. Success could spell more business for processors of double-walled plastics sheet in the construction industry.

Nanogel is a translucent, hydrophobic silica aerogel, says Donald Beck, Cabot marketing manager Europe. The material, with granules sized .4 to 4 mm, are filled between twin-wall sheeting to improve thermal insulation by a factor of two to four times that of other materials currently in use. It reportedly has minimal light transmission loss; it is also a good sound insulator and diffuses light, reducing shadows and glare. Cabot claims it is the first to develop a manufacturing process that can economically produce aerogels for markets other than aerospace applications.

Nanogel bulk density is only 90 to 100 kg/cu m, so architects and builders needn''t redesign window supports to adjust for added weight. Filled-sheet weight usually falls within the limits of supports already used. Late last year the supplier formed an agreement with the Structured Products division of GE to comarket Thermoclear twin-wall polycarbonate sheet filled with Nanogel.

Flammability tests at Dutch research center TNO show multiwall PC filled with Nanogel earns an S1 classification in smoke buildup (no smoke) and a d0 classification (no burning droplets). Beyond the construction market, Beck sees its potential as a sound deadener in automotive parts. Cabot Corp., Boston, MA, USA; +1 617-342- 6254; www.cabot-corp.com/nanogel

ADDITIVES Agents clear up haze, improve productivity

Clearlite NU004 is a micronized, sodium benzoate-based additive to increase the overall crystallization levels of semi-crystalline polymers. It improves mechanical and physical properties. Another new grade, sorbitol-based NU005, in addition to its nucleating effects, clarifies polymers to reduce haze and improve transparency. The additives can be used in a wide range of housewares and packaging products. Great Lakes Chemical Corp., Indianapolis, IN, USA; +1 317-715-3000; www.greatlakes.com

Semifinished goods Agricultural films block UV, transmit visible light

Thermic films used to increase plant growth, speed up harvests, and create more abundant quality produce have traditionally been made from LDPE that used mineral fillers, or coextrusion with vinyl acetate (EVA) or butyl acrylate (EBA) to achieve optimum infrared (IR) radiation transmission. Repsol YPF has developed a compound for agricultural films using a new family of mineral fillers that reportedly won''t degrade or reduce visible light transmission, and can provide very low or very high haze, depending on what''s needed.

Ideally, films must block IR radiation between 7 and 14 µm, but still be transparent to the visible portion of the light spectrum that fuels the photosynthetic process. A good film can also reduce the risk posed by frost and lower the energy consumed when heating a greenhouse.

In experiments conducted by IMAG Institute (Wageningen, the Netherlands) comparing Repsol''s clear ultra-thermic (CUT) film to a three-layer coextruded film containing EVA without mineral fillers, it was determined that a tomato crop under the CUT film used 8.3% less energy than a tomato crop facing similar conditions under the EVA film. In an experiment made to replicate clear, direct-light days of a hotter sun, hazier films with values up to 90% light transmission and IR blocking of 97% were proved. Repsol YPF, Madrid, Spain +34 91 3484015; www.repsol-ypf.com

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