"Airplanes are a specific and highly technical challenge for coatings manufacturers. Aircraft need to be able to deal with temperatures ranging from -55°C in the air to +55°C on the ground, as well as having to stand strong UV irradiation at 30,000 feet. ..."

Robert van Kooperen, ANAC Product Manager

Manchester Team Flies High in Lightweight Coating

ANAC’s fillers, primers and topcoats such as the Eclipse®, Aviox®, Aerowave®, Alumigrip® and Intergard® brands are approved by over 60 OEMs operating in the commercial and general aviation sector worldwide. For example, Aviox Finish 77702 is a high-solids, lead-free, sag-resistant topcoat that has already gained a reputation in the aerospace industry for excellent color stability achieved in just two coats for most colors. The low film density, at equal layer thicknesses, reduces the overall aircraft weight, an important consideration today.

Manchester’s star players are flying high across Asia, thanks to an aircraft livery using the thin-film topcoat. The club has a huge following in Asia. In honor of its sponsorship as the official low-fare airline for Manchester United, AirAsia’s in-house design team created a special tribute on one of the company’s A320 Airbus aircraft.

The coating is formulated to be easy to apply and can be polished (during the first 48 hours after application) rather than reworked to maintain the high-gloss finish, reducing process and maintenance time, cutting labor costs, and improving coating schedules. Aviox Finish 77702 is also highly resistant to UV damage and to staining from oil, hydraulic fluids and other chemicals. It can be applied successfully in a wide range of climatic conditions.

AirAsia chose the paint system because of its weight-saving benefits and subsequent fuel savings. The superior gloss quality of the new product also met the high standards set for the airline’s branding image.

“Airlines spend millions on different ways of cutting the weight of aircraft to save on fuel costs, looking at everything from floor panels to seating,” commented ANAC’s Product Manager Robert van Kooperen. “The weight of coatings can, and does, make a measurable difference in this respect. With current technology, it’s now possible to cut the coating weight without compromising on performance. Our new-generation Aviox Finish 77702 thin-film topcoat is typically about 15% lighter than previous products, and in most colors achieves its optimum performance in just two coats.”

Coating Stretches With Wing Movement

Condor specified ANAC’s pioneering Aeroflex HS 113FO2, a polyurethane ‘in-spar’ wing coating, used on the upper surface of the wing, where a coating must stretch with the wing movement during flight to avoid cracking. The ‘film elongation’ properties of the new system by far outperform any other product on the market, claims ANAC, as well as meeting today’s demands for long-lasting high gloss, fewer layers, lower cost and VOC (volatile organic compound) compliance.2

About 250 gallons of PPG primers and high-solids topcoat were used to paint the fuselage and vertical fin of the first Airbus A380. Credit: Airbus.

PPG Aerospace Coatings Systems Launched for Boeing, Airbus Aircraft

PPG Aerospace – PRC-DeSoto coatings experts have developed chromate-free, selectively strippable systems (SSS) for painting aircraft surfaces that cut refinish cycle time commonly by 40 percent, reduce worker fatigue and are environmentally friendly, company officials say.

Paul Bowman, PPG global platform business manager, aerospace coatings, calls the SSS technology “an industry breakthrough” because it allows chemical stripping of composite and metal surfaces with environmentally friendly strippers that are less invasive than hand-sanding operations.

 “Although PPG has some current customers using a version of the selectively strippable system for aircraft refinishing, the chromate-free PPG Aerospace selectively strippable systems are launching on the Airbus A380 and Boeing 787 Dreamliner airplanes,” Bowman said.

 “For the first time ever, airplane maintenance personnel can strip composite surfaces chemically instead of using the labor-intensive and potentially damaging manual sanding process,” Bowman said. “The time-saving is huge. We are seeing painting firms commonly cut cycle time by 40 percent or more. As a result, airlines are able to get planes back into service faster for reduced downtime and improved profitability.”

Bowman said the key to the PPG systems is the layering of coatings that are formulated to work together.

PPG’s new selectively strippable systems consist of chromate-free Desoprime® CA7501 composite epoxy primer for the Boeing 787 Dreamliner and chromate-free Desoprime CA7049 composite epoxy primer for the Airbus A380, F565-4010 chromate-free intermediate coating, and Desothane HS CA8000 polyurethane topcoat.

According to Bowman, PPG Aerospace is also developing a new low-VOC exterior basecoat/clearcoat that will provide Boeing and Airbus customers with a unique combination of properties: fast cure, very low density and improved durability for prolonged service life compared with current materials.

 Bowman said the systems minimize the number of products required because of compatibility with composites as well as metal substrates, reducing the number of coating layers and required thickness on the aircraft.

“Desoprime HS CA7501 primer has been formulated to meet the rigorous performance requirements of aircraft fuel tanks,” Bowman noted. “As a result, aircraft maintenance personnel are able to use one primer for the entire aircraft instead of separate ones for the body, wings and fuel tanks.”

 According to Alan Schoeder, PPG global segment manager, commercial aerospace coatings, the new PPG selectively strippable system primers stay on the airframe surface during repainting. “So stripping time for an in-service aircraft can be reduced by as much as 24 hours,” Schoeder said.

“The intermediate coat is then applied, rather than having to re-seal, wash and prepare the surface for another 24-hour saving. The finish and other colors are then applied for an estimated strip-and-repaint cycle of five days, compared with a conventional cycle of nine or 10 days.”

 New chromate-free Desoprime CA7049 high-solids primer has been formulated to replace existing chromated primers used in the Airbus paint process while being suitable for composite structures as well.

Because most chemical strippers cannot be used on composite structures, airlines commonly sand composite parts to prepare them for repainting. As much as 95 percent of the Boeing 787 Dreamliner’s exterior surface and almost 30 percent of the A380’s exterior surface are expected to be composite materials, making sanding extremely labor intensive, according to Schoeder. Additionally, the potential for damaging the expensive composite skins is extremely high when using manual sanding processes, so the SSS is a logical choice, according to Schoeder.

With the new PPG selectively strippable systems, Desoprime chromate-free high-solids epoxy primers would be applied to the bare metal and composite surfaces, then F565-4010 chromate-free intermediate coating, and finally Desothane HS CA8000 polyurethane topcoat would be applied. When repainting is needed, the topcoat and intermediate coating are quickly removed with a mild chemical stripper such as Eldorado PR-3131E, leaving Desoprime primer intact.3


PPG Aerospace Coatings Fly on First Airbus A380

While airlines that take delivery of the new Airbus A380 will be able to specify PPG’s new selectively strippable system, the first A380 aircraft was coated with aerospace primers and Desothane HS CA 8000 high-solids polyurethane topcoat made by PPG. The new colors were created for Airbus by PPG at its Le Havre, France, aerospace coatings laboratory and Hamburg, Germany, application support center.

“The primary characteristic for an aircraft topcoat is to look good,” said Alan Schoeder. “Coatings protect the airframe but they add weight. Using our Desothane HS high-solids topcoat enabled Airbus to achieve the coverage needed with about 100 fewer gallons of paint than would have been used with conventional-solids topcoats.”

Desothane HS CA 8000 exterior high-solids, low-VOC topcoat is approved and in use by Airbus and Boeing. It contains 55 percent solids by volume, compared with 30 percent for conventional topcoats. As a result, it is more economical for aircraft to be painted with the PPG topcoat because fewer gallons are used. Desothane HS topcoat has 40 percent less solvent per volume than conventional topcoats, reducing environmental impact and complying with worldwide environmental regulations.

The A380s delivered to Singapore Airlines, which is set to become the first airline to fly the A380 when it enters commercial service, are the first to use PPG’s new-generation chromate-free high-solids Desoprime CA7049 primer.

High-Strength Coating Durable Over Wide Temp Range

NuSil Technology offers high-strength coatings for aircraft applications. R-2180, for example, is a two-part silicone dispersion that cures rapidly with heat. Its low viscosity makes it an ideal candidate for spraying or dipping applications. Once cured, NuSil’s R-2180 is durable over a wide temperature range and provides a tough, hydrophobic barrier.4

“This product expands our line of aircraft silicones and offers other industries like automotive and marine a tough silicone coating,” said Brian Nash, vice president of marketing and sales. “We are also working on other versions that offer fuel and temperature resistance for extremely harsh environments.”

Silicone Coating System Protects Space Shuttle Hardware

he Space Shuttle occupies a Low Earth Orbit (LEO) in the performance of its missions. The LEO presents a hostile environment to organic materials used on the shuttle, and the KU-band antenna reflector had exhibited damage due to the effects of LEO atomic-oxygen erosion. A coating was required that would protect the exposed surfaces; it also had to meet the following criteria:

  • No RF impact,
  • No thermal impact,
  • Field-repair capability,
  • Ease of application,
  • Minimal mass property changes, and
  • Ability to survive projected shuttle life with minimal maintenance and shuttle compatibility.

A number of protective coating systems were tested, taking into consideration both performance and manufacturing needs. One system, a silicone coating from NuSil Technology, was the clear choice for the coating to use. CV1144 is a flexible, room-temperature-curing coating formulated for protecting space hardware from the LEO environment. It can be spray-applied for a fractional-mil coating thickness or brushed on to repair damage. It is non-corrosive and uses an oxime-curing system that is not easily poisoned. It meets NASA out-gassing requirements and provides an effective barrier against oxygen erosion. The coating system does not affect the operation of the reflector while providing protection to the LEO environment for extended periods. 5

“Airplanes are a specific and highly technical challenge for coatings manufacturers. Aircraft need to be able to deal with temperatures ranging from -55°C in the air to +55°C on the ground, as well as having to stand strong UV irradiation at 30,000 feet. On the ground, aircraft coatings also have to cope with various fluids, which could act as a solvent or are otherwise aggressive, such as aviation fuel, de-icing fluids, hydraulic fluids and so on. In addition, the coatings need to be resistant to the impact of dust traveling at 900 km/hr, which has an effect similar to sandpaper.

“The coatings also need to withstand the vibration effect of incredibly powerful engines, and aircraft hull and wing movements. In addition, airplanes usually have to be colorful and attractive, while developing coatings that are less damaging to the environment is becoming increasingly important.

“So, it’s hardly surprising that the highly regulated and extremely demanding aviation sector has seen the development of technologically advanced coatings that address these very specific needs.”1

ANAC (Akzo Nobel Aerospace Coatings), Arnhem, The Netherlands; PPG Aerospace, Glendale, Calif.; and NuSil Technology LLC, Carpinteria, Calif.; make a range of products that meet one or more of the stringent demands of the aerospace industry described above. Following are some of the products these companies have recently introduced.