PPG Announces Revolutionary Secondary Fuel Vapor Barrier Sealant for Transport Aircraft

A new sprayable secondary fuel vapor barrier is in development by PPG that uses ultraviolet (UV) radiation to cure in seconds instead of 24 hours or more and can greatly reduce production cycle times for commercial aircraft manufacturers and subcontractors. The revolutionary PPG eco-friendly sealant uses PERMAPOL polymer technology and is expected to be commercialized in early 2018.

Aviation certification authorities require application of secondary fuel vapor barriers to the exterior of center wing box fuel tanks for all transport aircraft having them. These sealants are elastomeric coatings that provide a redundant level of sealing should the internal primary integral fuel tank seals ever be compromised. They are intended to protect, or contain, any vapor and fuel from leaking into the cargo bay and contacting electrical cables, which could have catastrophic consequences.

Bill Keller, PPG global market segment manager for aerospace sealants, said the new PPG secondary fuel vapor barrier offers the greatly reduced production cycle times required to build planes faster and with greater efficiency.

“I have met with aircraft manufacturers from around the world who said having a rapid-curing, easy-to-use product was an absolute priority,” Keller said. “A UV-cured, sprayable secondary fuel vapor barrier sealant based on Permapol technology by PPG will be a perfect fit for these customers.”

Traditionally, products used for these applications are two-part, chemical-cured polyurethanes. When applied in the production assembly environment, the material requires at least 24 hours for curing after application, curtailing other assembly operations in the proximity. This becomes a major rate-limiting factor for aircraft production.

The PPG UV-cured secondary fuel vapor barrier eliminates this bottleneck. The material is spray-applied, and then a UV light is used to completely cure the coating in just a few seconds. After this, all assembly operations can be resumed immediately.

In addition to curing speed, the product offers other benefits when compared with currently available secondary fuel vapor barriers. It has lower solvent content, is isocyanate free, and cures to a totally clear transparent coating that enables easy structural inspection.

Keller said that multiple transport aircraft manufacturers are intensely interested in the technology and how it can improve their productivity.

Paris Air Show attendees can learn more about PPG’s new secondary fuel vapor barrier and other sealants that use ultraviolet radiation for on-demand curing by visiting Hall 2b Stand C105 and talking with PPG aerospace sealants experts. The International Paris Air Show is June 19-25 at Le Bourget.