Kerry Pianoforte, Editor05.08.20
Towards the end of 2019, all indications were the aerospace coatings market was poised for growth. The COVID-19 crisis has drastically altered those forecasts.
“At the beginning of this year, we completed an extensive survey of the U.S. MRO marketplace which concluded that the industry entered 2020 in growth mode,” said Julie Voisin, global marketing manager, Sherwin-Williams Aerospace Coatings. “More than 60 percent of responding MRO Maintenance Directors and Paint Supervisors said they planned to increase their aerospace coatings purchases. In addition, a majority were looking to increase both the footprint of their maintenance or painting facility, as well as many looking to hire more technicians if possible.”
As a result of the COVID-19 crisis, Sherwin-Williams has been taking action to support employees, customers and communities. “We have taken a number of steps in response to this public health emergency, adjusting our business operations to protect our employees while continuing to meet our customers’ needs,” Voisin added.
PPG’s aerospace coatings experienced double-digit growth in 2019 versus the prior year, driven by higher sales volumes. “This increase was supported by market outperformance in all major platforms stemming from technology-advantage products and robust industry demand,” said Daniel Bencun, PPG global director, aerospace coatings.
“As you can imagine, this crisis is affecting PPG’s global businesses in many ways, some of which will extend beyond the current crisis,” explained Bencun. “The aerospace industry has been dramatically impacted, and aviation traffic has been dramatically reduced, dampening demand for some of our products. In many facilities around the world, we’ve adjusted production to account for a significant reduction in customer demand and lighter economic activity.”
With many airplanes grounded during this pandemic, PPG noted that it is helping its customers protect their fleets with its temporary and protective aerospace coatings.
“Environmentally friendly products such as Z6160 and Z6148 peelable temporary protective coatings help aircraft preservation while at the same time are easier to remove when the aircraft is ready to get back in service,” said Bencun. “PPG’s commitment to protect and beautify is evident in everything from our coatings to protect unpainted structures from corrosion during storage to our peelable preservation systems that protect planes from the environmental conditions during storage.”
According to John Griffin, AkzoNobel’s Aerospace business director, the aerospace coatings market continued to grow in 2019, albeit at a slower rate than in previous years. “Airbus had record deliveries in 2019, and high-performance coatings continue to support these production increases. Boeing deliveries in 2019 were severely impacted by the 737MAX issues.”
“Like most of all global industries, the aerospace coatings industry has been affected by COVID-19,” Griffin noted. “In our Q1 report, we stated that the demand for aerospace coatings started strong and decreased at the end of the quarter. At AkzoNobel, our priority is to keep our employees, their families, and our partners safe and well. We are closely monitoring the pandemic situation and taking all necessary measures. We fully support and follow national and local government requirements.”
“We are also taking all reasonable steps to continue serving our customers and maintain business continuity,” Griffin continued. “Our sourcing team is working closely with our suppliers to proactively manage our raw material supply. We are monitoring and managing the extent and duration of any local requirements impacting/related to our physical locations. Our focus is to ensure we can continue to support the industry and our customers for the long term and as the situation evolves, we will adapt our
actions accordingly.”
“It is too early to predict exactly what consequences the situation will have,” said Andreas Ossenkopf, director – head of Aviation at Mankiewicz. “One result is that other products come into the center of attention. A focus on hygiene in the cabin was present well before COVID-19, but in the current situation, it has gained enormously in significance. Mankiewicz has already worked for several years on the development of a paint system with antimicrobial effective additives and this resulted in ALEXIT FST BioProtect, a topcoat based on silver technology that inhibits mildew grows / bacterial odors on surfaces painted with it. After a single application, the product has proven its effectiveness for more than a decade now.”
The described effect is based on silver technology. “Silver ions, as they are contained in ALEXIT FST BioProtect, are highly reactive and they interrupt vital processes in the bacterial cells, ultimately killing them,” said Ossenkopf. “However, on human cells, the silver ions have no negative effect. The effectiveness of silver against bacteria has been known for centuries and successfully used for many purposes. Another advantage of ALEXIT BioProtect is that the silver it contains does not wear off and remains active for many years. The topcoat thus protects the painted surfaces for a long time without it having to be renewed. In lavatories, the product has been used for several years and has already successfully proven its effectiveness there.
Aerospace coatings manufacturers, now more than ever, must deliver products that offer high performance and cost-saving. Reducing coatings weight on painted aircraft has long been on the aerospace industry’s radar and it remains priority number one. Lowering the weight of an aircraft improves fuel efficiency that can result in significant operating cost savings and reduced greenhouse gas emissions when translated across a fleet.
“Aircraft painters, maintenance operations and airframe manufacturers have quickly adopted basecoat-clearcoats that offer reduced painted aircraft weight with many other benefits,” said Bencun. “Compared with traditional direct-gloss systems, basecoat-clearcoats have higher pigment load and coverage and can save weight even with an additional clear coat layer. PPG DESOTHANE HD basecoat-clearcoat allows customers with liveries that have medium to high complexity to reduce the weight of coatings on their aircraft by up to 20 percent.”
New pretreatments and primers are also being developed that offer weight savings. A few years ago, PPT launched PPG DESOPRIME 7530 pretreatment primer that customers can apply with electrostatic spray equipment. This technology combined with PPG Desoprime 7065 polyurethane primer offers a better transfer ratio, which allows customers to reduce weight.
“Another weight-reducing product is PPG AEROCRON electrocoat (e-coat) primer, which is used to coat structural parts by electrodeposition instead of a traditional spray process, brings uniform film on the part,” said Bencun. “This can result in up to 75 percent weight savings on highly complex parts. In addition, it offers high transfer efficiency and is an environmentally sustainable technology.”
The increased use of composites is also changing the aerospace industry and customer requirements. “Since composites are lighter than metals, they provide opportunities to save weight on the aircraft,” said Bencun. “Also, their ability to be molded provides original equipment manufacturers (OEMs) the opportunity to redesign and make complex parts in less time and with different mounting structures. Applied over composites, PPG Desoprime HS 7700 primer helps provide surface protection and leveling of the substrate. We also have a family of composite surfacers and trowelable grade fillers that meet the ergonomic and performance characteristics desired by the industry.”
“Some of the latest Basecoat/Clearcoat topcoats, such as Sherwin-Williams SKYscapes, not only provide better coverage but use less paint in doing so,” said Voisin. “Plus, it can provide full-color hide with lower film build through excellent opacity with our toner systems.”
“Aircraft manufacturers always welcome weight reductions, especially during the design and certification phases,” said Griffin. “Our products contribute to these benefits, but we mainly focus on developing high-performing, functional products. Our Aerobase and Aerodur basecoat/clearcoat systems were developed to improve durability and reduce application time. But by optimizing our color formulation for optimum brightness and opacity, the product potentially helps minimize total aircraft weight thanks to fewer layers and lower film build and weight. We also provide and continue to develop coating systems for composites, thermoplastics, and lighter substrates and thus support manufacturers with minimizing reducing aircraft weight. “
“Weight is indeed of high concern to the airline. Every kg on the aircraft makes a big difference in the operational costs,” said Ossenkopf. “When talking about paint, two main aspects have to be considered: the paint itself and the application process or sequence. On the first, Mankiewicz works continuously in adjusting the pigment concentration in products to achieve the best results by optimizing the weight of the dry film layer. The use of special research techniques allows Mankiewicz´s researchers to play with the tolerances defined by the different specifications in an effort of satisfying these but still the same some grams on each iteration.”
On the other hand, Mankiewicz continuously works with Airlines and MROs on defining best practices. “Only working closely with the user of our products, the smoothest and most efficient results can be achieved, resulting in the potential reduction of paint consumption and ultimately reduction of weight,” Ossenkopf added.
According to Bencun, in addition to weight reduction, aerospace customers are looking for products that have desirable environmental, health and safety qualities, and are more cost-effective. “Therefore, our innovation and research are based around these concepts. Our products need to be suitable for more automated processes and offer faster curing times. An aircraft in the hangar is an immobilized asset that is not generating revenue for the customer. There is an opportunity for us to help customers increase that revenue by reducing paint cycle time through better application processes and faster-drying products. Our customers also require more services such as product training, technical service and support, marketing support and coatings services. Through closer partnerships, we will be able to deliver higher value to our customers and better protect their assets that millions of individuals use every day.”
Sherwin-Williams’ recent MRO survey indicated product durability to be the number one performance characteristic its customers demand. “We find durability is a real deep-dive question that begins with the quality of the raw materials and formulas used in the manufacturing process of the coating. We want the paint scheme to look amazing for the life of the airplane. We want it to look like a fresh paint job for years. The entire process, from the coating type, mixing the product, aircraft preparation, to paint application, has a role in durability.
The survey then pointed out that product ease of use is the second most important attribute. Like the durability question, ease of use is all part of the entire process. Just like maintainability all these attributes are interrelated – durability, ease of application, maintainability, etc. They all affect how a reworked section of an aircraft appears after some work has been performed.
Two key trends that guide AkzoNobel’s developments are reducing the total cost of ownership and complying with the ever-changing regulatory environment. “Total cost of ownership includes the durability of coatings, ease of application, process time, and the cost per liter/surface area,” said Griffin. “Of all of these, durability is by far the biggest contributor to the total cost of ownership. Delaying the need to repaint aircraft or components saves significant costs in terms of material and application. Additionally, if aircraft do not need to be grounded for repainting, they can continue to generate revenue or be mission-ready.”
Griffin said he sees a continued shift to basecoat/clearcoat in the industry; technologies that were developed to improve durability and reduce application time. “We have since found further ways to optimize our color formulation for optimum brightness and opacity, leading to fewer layers and lower film builds, potentially reducing weight. Enhanced durability is one of many reasons why many airlines are switching to our basecoat/clearcoat systems, including Aerobase and Aerodur 3001/3002.”
Another important topic is chemical stripping. “After aircraft have reached the end of a maintenance cycle, they must be repainted according to OEM specifications, said Ossenkopf. “To avoid adding unnecessary additional weight, the old paint system must first be removed. This is normally done by chemical stripping. Chemical strippers normally work well on the aluminum skins of aircraft. However, modern aircrafts such as the Airbus A350 or Boeing 787 are mainly made of composite materials, which can suffer from a chemical stripping process. The only alternative would be to sand down the old coating layers: a mechanical process that is labor-intensive and costly. It also results in the painting process getting very long, requiring the aircraft to remain longer on the ground for maintenance and consequently impacting the airlines by loss of service revenue.
“For that reason, OEMs require what is known as a selectively strippable system for aircraft made of composites. This consists of a barrier layer that prevents the stripper from attacking the layers below it and the composite, which remain completely intact. As well as making the time-consuming process of sanding down the aircraft unnecessary, it also saves reapplying the basic primer and the exterior primer.”
Boeing has recently qualified as an optimal solution for a further product of Mankiewicz – CELEROL IntermediateCoat 990-09. The first Boeing 787 aircraft to use this selectively strippable system is already complete and the advantages of the CELEROL IntermediateCoat are clearly visible, according to the company. The system is particularly characterized by its robustness, its simple and safe application and providing significant savings of time and cost. CELEROL IntermediateCoat can now be used for painting in the production and refurbishment of B787 aircraft.
“The factors that helped Boeing decide for CELEROL IntermediateCoat were not only that the system acts as a barrier and enables good stripping, but also the excellent application features of the product,” said Ossenkopf. “The system allows us to use special chemicals for stripping, which are less aggressive than conventional ones, making it safer for the environment as well as for the staff using it. Mankiewicz CELEROL IntermediateCoat 990-09 has been qualified by Airbus for many years and is routinely used for production aircraft. Now Boeing has also decided in favor of the Selective Strippable System by Mankiewicz as standard for use on its airplanes made of composites.”
The repaint cycle depends on the airline, region and original coatings technology applied. “We are seeing the repaint cycle increasing and going beyond the traditional five to six years, but this is not becoming the new standard yet,” said Bencun.
Both PPG Desothane HD basecoat-clearcoat and PPG Aerocron electrocoat primer provide potential opportunities to increase productivity. “PPG Desothane basecoat-clearcoat technology offers higher chemical resistance and higher erosion protection that can extend the life of a paint job,” said Bencun. “Airlines are able to operate their aircraft longer with fewer repaint cycles. PPG Aerocron primer, where metal parts are dipped into an electrically charged tank containing primer, offers significant process time savings. Thermal curing occurs in about 30 minutes, while spray primers typically require seven days to cure fully. As a result, parts can be coated and put back onto the aircraft more quickly, so aircraft are back in service sooner.”
“Aircraft are being repainted and/or the livery changed for a variety of reasons - the plane may be sold, leased to someone new, reached its required maintenance checks, or the owner just wants something different,” said Voisin. ”In the business jet world, it would not be unusual for the plane to be repainted in the five to seven-year range. As far as commercial aircraft, it is more related to the required maintenance checks and the amount it is flown.”
New products
PPG has launched several technologies in recent years, and now is working on enlarging and expanding its qualified systems portfolio. “In pretreatment, for example, we have qualified PPG RECC 3007 sprayable chrome-free pretreatment to U.S. Military Specification MIL-C-81706, Type II, Class 3, Form IV, Method A,” said Bencun. “The pretreatment is formulated without chrome as an intentionally added ingredient.”
“Our chrome-free primer technologies, including PPG Aerocron e-coat primer, are being approved by a growing number of OEMs and tier-one subcontractors,” he continued. “PPG CA7088 chrome-free integral fuel tank coating has been qualified to SAE International’s Aerospace Material Specification AMS-C-27725, Type 3, Grade 2. The coating can help protect the interior of an aircraft’s fuel tank against corrosion from fuel contaminants, such as water, saltwater, aircraft fuels, hydraulic fluids, engine oils and dilute acid solutions, as well as diethylene glycol monomethyl ether (DiEGME). It is one of the first chrome-free coatings for use in fuel tanks.”
PPG Desothane HD basecoat-clearcoat has three new AMS3095A qualifications, and one major player in the industry has approved the same version with solar heat management. Airlines often avoid using dark colors in their liveries because they can absorb solar energy that heats the interior while the plane is on the ground. With this technology, the coating reduces external aircraft skin temperatures, helping keep interior cabin temperatures cooler by five to seven degrees Fahrenheit, so airlines can use dark colors in their liveries.
Sherwin-Williams’ SKYscapes and SKYscapes GA (General Aviation) Basecoat/Clearcoat and SKYscapes Shimmer Basecoat, the special effects system from S-W continue to gain more usage within the MRO universe. They allow aviation maintenance repair facilities and their paint shops to augment production schedules and improve turnaround time. Sherwin-Williams is still seeing a need to provide traditional single-stage technology exterior coating systems such as its Jet Glo and Jet Glo Express - both polyester
urethane coatings.
AkzoNobel’s new chromate-free exterior primer, Aerodur HS 2121 was developed with and qualified at Airbus. For airlines, Aerodur HS 2121 promotes superior sustainability of the brand image and improves selective stripping of the decorative layer, enhancing rivet adhesion and reducing maintenance downtime. It was developed to meet all Airbus exterior system specifications, including the selective strippable systems. The product received its qualification from Airbus in March 2019.
“In addition, we recently qualified our Aerodur 2111, a second-generation chrome-free primer, to Boeing specification BMS 10-72,” said Griffin, The updated Qualified Products List was released in 2019 and since then, hundreds of aircraft (in OEM and MRO) have been coated with this primer.”
“We are very proud to have acquired French aerospace coatings manufacturer Mapaero in late 2019,” said Griffin. “We are currently working to merge the combined product offer and give our customers access to a broader range of products to meet their needs. The key additions to our portfolio are the Airbus-approved FR2-55 water-based interior cabin coating, the P60/F70 range of structural coatings, and a very unique touch-up kit package. This versatile new package enables the use of multi-component coatings without having to pour or mix small quantities, enabling customers to quickly and cleanly complete touch-up work.”
“Not a new product, but [importantly] is the authorization of our CELEROL WashPrimer despite REACH,” said Ossenkopf. “For a number of years now, one of the main topics in aircraft painting has been the effect of REACH and how end-users will have to adapt. In addition to developing further chromate-free coating solutions, Mankiewicz has taken up this issue and is committed to making the changeover as pleasant as possible for its customers. This is why Mankiewicz has decided to have CELEROL WashPrimer 913-21 officially authorized. This allows customers to use the product at least until 22.01.2026, giving them more time to thoroughly plan a switch to chrome-free alternatives while making sure to proceed business as usual. The authorization will help customers with their sustainability plans, letting them decide when and if they move to other systems at their own pace.”
“At the beginning of this year, we completed an extensive survey of the U.S. MRO marketplace which concluded that the industry entered 2020 in growth mode,” said Julie Voisin, global marketing manager, Sherwin-Williams Aerospace Coatings. “More than 60 percent of responding MRO Maintenance Directors and Paint Supervisors said they planned to increase their aerospace coatings purchases. In addition, a majority were looking to increase both the footprint of their maintenance or painting facility, as well as many looking to hire more technicians if possible.”
As a result of the COVID-19 crisis, Sherwin-Williams has been taking action to support employees, customers and communities. “We have taken a number of steps in response to this public health emergency, adjusting our business operations to protect our employees while continuing to meet our customers’ needs,” Voisin added.
PPG’s aerospace coatings experienced double-digit growth in 2019 versus the prior year, driven by higher sales volumes. “This increase was supported by market outperformance in all major platforms stemming from technology-advantage products and robust industry demand,” said Daniel Bencun, PPG global director, aerospace coatings.
“As you can imagine, this crisis is affecting PPG’s global businesses in many ways, some of which will extend beyond the current crisis,” explained Bencun. “The aerospace industry has been dramatically impacted, and aviation traffic has been dramatically reduced, dampening demand for some of our products. In many facilities around the world, we’ve adjusted production to account for a significant reduction in customer demand and lighter economic activity.”
With many airplanes grounded during this pandemic, PPG noted that it is helping its customers protect their fleets with its temporary and protective aerospace coatings.
“Environmentally friendly products such as Z6160 and Z6148 peelable temporary protective coatings help aircraft preservation while at the same time are easier to remove when the aircraft is ready to get back in service,” said Bencun. “PPG’s commitment to protect and beautify is evident in everything from our coatings to protect unpainted structures from corrosion during storage to our peelable preservation systems that protect planes from the environmental conditions during storage.”
According to John Griffin, AkzoNobel’s Aerospace business director, the aerospace coatings market continued to grow in 2019, albeit at a slower rate than in previous years. “Airbus had record deliveries in 2019, and high-performance coatings continue to support these production increases. Boeing deliveries in 2019 were severely impacted by the 737MAX issues.”
“Like most of all global industries, the aerospace coatings industry has been affected by COVID-19,” Griffin noted. “In our Q1 report, we stated that the demand for aerospace coatings started strong and decreased at the end of the quarter. At AkzoNobel, our priority is to keep our employees, their families, and our partners safe and well. We are closely monitoring the pandemic situation and taking all necessary measures. We fully support and follow national and local government requirements.”
“We are also taking all reasonable steps to continue serving our customers and maintain business continuity,” Griffin continued. “Our sourcing team is working closely with our suppliers to proactively manage our raw material supply. We are monitoring and managing the extent and duration of any local requirements impacting/related to our physical locations. Our focus is to ensure we can continue to support the industry and our customers for the long term and as the situation evolves, we will adapt our
actions accordingly.”
“It is too early to predict exactly what consequences the situation will have,” said Andreas Ossenkopf, director – head of Aviation at Mankiewicz. “One result is that other products come into the center of attention. A focus on hygiene in the cabin was present well before COVID-19, but in the current situation, it has gained enormously in significance. Mankiewicz has already worked for several years on the development of a paint system with antimicrobial effective additives and this resulted in ALEXIT FST BioProtect, a topcoat based on silver technology that inhibits mildew grows / bacterial odors on surfaces painted with it. After a single application, the product has proven its effectiveness for more than a decade now.”
The described effect is based on silver technology. “Silver ions, as they are contained in ALEXIT FST BioProtect, are highly reactive and they interrupt vital processes in the bacterial cells, ultimately killing them,” said Ossenkopf. “However, on human cells, the silver ions have no negative effect. The effectiveness of silver against bacteria has been known for centuries and successfully used for many purposes. Another advantage of ALEXIT BioProtect is that the silver it contains does not wear off and remains active for many years. The topcoat thus protects the painted surfaces for a long time without it having to be renewed. In lavatories, the product has been used for several years and has already successfully proven its effectiveness there.
Aerospace coatings manufacturers, now more than ever, must deliver products that offer high performance and cost-saving. Reducing coatings weight on painted aircraft has long been on the aerospace industry’s radar and it remains priority number one. Lowering the weight of an aircraft improves fuel efficiency that can result in significant operating cost savings and reduced greenhouse gas emissions when translated across a fleet.
“Aircraft painters, maintenance operations and airframe manufacturers have quickly adopted basecoat-clearcoats that offer reduced painted aircraft weight with many other benefits,” said Bencun. “Compared with traditional direct-gloss systems, basecoat-clearcoats have higher pigment load and coverage and can save weight even with an additional clear coat layer. PPG DESOTHANE HD basecoat-clearcoat allows customers with liveries that have medium to high complexity to reduce the weight of coatings on their aircraft by up to 20 percent.”
New pretreatments and primers are also being developed that offer weight savings. A few years ago, PPT launched PPG DESOPRIME 7530 pretreatment primer that customers can apply with electrostatic spray equipment. This technology combined with PPG Desoprime 7065 polyurethane primer offers a better transfer ratio, which allows customers to reduce weight.
“Another weight-reducing product is PPG AEROCRON electrocoat (e-coat) primer, which is used to coat structural parts by electrodeposition instead of a traditional spray process, brings uniform film on the part,” said Bencun. “This can result in up to 75 percent weight savings on highly complex parts. In addition, it offers high transfer efficiency and is an environmentally sustainable technology.”
The increased use of composites is also changing the aerospace industry and customer requirements. “Since composites are lighter than metals, they provide opportunities to save weight on the aircraft,” said Bencun. “Also, their ability to be molded provides original equipment manufacturers (OEMs) the opportunity to redesign and make complex parts in less time and with different mounting structures. Applied over composites, PPG Desoprime HS 7700 primer helps provide surface protection and leveling of the substrate. We also have a family of composite surfacers and trowelable grade fillers that meet the ergonomic and performance characteristics desired by the industry.”
“Some of the latest Basecoat/Clearcoat topcoats, such as Sherwin-Williams SKYscapes, not only provide better coverage but use less paint in doing so,” said Voisin. “Plus, it can provide full-color hide with lower film build through excellent opacity with our toner systems.”
“Aircraft manufacturers always welcome weight reductions, especially during the design and certification phases,” said Griffin. “Our products contribute to these benefits, but we mainly focus on developing high-performing, functional products. Our Aerobase and Aerodur basecoat/clearcoat systems were developed to improve durability and reduce application time. But by optimizing our color formulation for optimum brightness and opacity, the product potentially helps minimize total aircraft weight thanks to fewer layers and lower film build and weight. We also provide and continue to develop coating systems for composites, thermoplastics, and lighter substrates and thus support manufacturers with minimizing reducing aircraft weight. “
“Weight is indeed of high concern to the airline. Every kg on the aircraft makes a big difference in the operational costs,” said Ossenkopf. “When talking about paint, two main aspects have to be considered: the paint itself and the application process or sequence. On the first, Mankiewicz works continuously in adjusting the pigment concentration in products to achieve the best results by optimizing the weight of the dry film layer. The use of special research techniques allows Mankiewicz´s researchers to play with the tolerances defined by the different specifications in an effort of satisfying these but still the same some grams on each iteration.”
On the other hand, Mankiewicz continuously works with Airlines and MROs on defining best practices. “Only working closely with the user of our products, the smoothest and most efficient results can be achieved, resulting in the potential reduction of paint consumption and ultimately reduction of weight,” Ossenkopf added.
According to Bencun, in addition to weight reduction, aerospace customers are looking for products that have desirable environmental, health and safety qualities, and are more cost-effective. “Therefore, our innovation and research are based around these concepts. Our products need to be suitable for more automated processes and offer faster curing times. An aircraft in the hangar is an immobilized asset that is not generating revenue for the customer. There is an opportunity for us to help customers increase that revenue by reducing paint cycle time through better application processes and faster-drying products. Our customers also require more services such as product training, technical service and support, marketing support and coatings services. Through closer partnerships, we will be able to deliver higher value to our customers and better protect their assets that millions of individuals use every day.”
Sherwin-Williams’ recent MRO survey indicated product durability to be the number one performance characteristic its customers demand. “We find durability is a real deep-dive question that begins with the quality of the raw materials and formulas used in the manufacturing process of the coating. We want the paint scheme to look amazing for the life of the airplane. We want it to look like a fresh paint job for years. The entire process, from the coating type, mixing the product, aircraft preparation, to paint application, has a role in durability.
The survey then pointed out that product ease of use is the second most important attribute. Like the durability question, ease of use is all part of the entire process. Just like maintainability all these attributes are interrelated – durability, ease of application, maintainability, etc. They all affect how a reworked section of an aircraft appears after some work has been performed.
Two key trends that guide AkzoNobel’s developments are reducing the total cost of ownership and complying with the ever-changing regulatory environment. “Total cost of ownership includes the durability of coatings, ease of application, process time, and the cost per liter/surface area,” said Griffin. “Of all of these, durability is by far the biggest contributor to the total cost of ownership. Delaying the need to repaint aircraft or components saves significant costs in terms of material and application. Additionally, if aircraft do not need to be grounded for repainting, they can continue to generate revenue or be mission-ready.”
Griffin said he sees a continued shift to basecoat/clearcoat in the industry; technologies that were developed to improve durability and reduce application time. “We have since found further ways to optimize our color formulation for optimum brightness and opacity, leading to fewer layers and lower film builds, potentially reducing weight. Enhanced durability is one of many reasons why many airlines are switching to our basecoat/clearcoat systems, including Aerobase and Aerodur 3001/3002.”
Another important topic is chemical stripping. “After aircraft have reached the end of a maintenance cycle, they must be repainted according to OEM specifications, said Ossenkopf. “To avoid adding unnecessary additional weight, the old paint system must first be removed. This is normally done by chemical stripping. Chemical strippers normally work well on the aluminum skins of aircraft. However, modern aircrafts such as the Airbus A350 or Boeing 787 are mainly made of composite materials, which can suffer from a chemical stripping process. The only alternative would be to sand down the old coating layers: a mechanical process that is labor-intensive and costly. It also results in the painting process getting very long, requiring the aircraft to remain longer on the ground for maintenance and consequently impacting the airlines by loss of service revenue.
“For that reason, OEMs require what is known as a selectively strippable system for aircraft made of composites. This consists of a barrier layer that prevents the stripper from attacking the layers below it and the composite, which remain completely intact. As well as making the time-consuming process of sanding down the aircraft unnecessary, it also saves reapplying the basic primer and the exterior primer.”
Boeing has recently qualified as an optimal solution for a further product of Mankiewicz – CELEROL IntermediateCoat 990-09. The first Boeing 787 aircraft to use this selectively strippable system is already complete and the advantages of the CELEROL IntermediateCoat are clearly visible, according to the company. The system is particularly characterized by its robustness, its simple and safe application and providing significant savings of time and cost. CELEROL IntermediateCoat can now be used for painting in the production and refurbishment of B787 aircraft.
“The factors that helped Boeing decide for CELEROL IntermediateCoat were not only that the system acts as a barrier and enables good stripping, but also the excellent application features of the product,” said Ossenkopf. “The system allows us to use special chemicals for stripping, which are less aggressive than conventional ones, making it safer for the environment as well as for the staff using it. Mankiewicz CELEROL IntermediateCoat 990-09 has been qualified by Airbus for many years and is routinely used for production aircraft. Now Boeing has also decided in favor of the Selective Strippable System by Mankiewicz as standard for use on its airplanes made of composites.”
The repaint cycle depends on the airline, region and original coatings technology applied. “We are seeing the repaint cycle increasing and going beyond the traditional five to six years, but this is not becoming the new standard yet,” said Bencun.
Both PPG Desothane HD basecoat-clearcoat and PPG Aerocron electrocoat primer provide potential opportunities to increase productivity. “PPG Desothane basecoat-clearcoat technology offers higher chemical resistance and higher erosion protection that can extend the life of a paint job,” said Bencun. “Airlines are able to operate their aircraft longer with fewer repaint cycles. PPG Aerocron primer, where metal parts are dipped into an electrically charged tank containing primer, offers significant process time savings. Thermal curing occurs in about 30 minutes, while spray primers typically require seven days to cure fully. As a result, parts can be coated and put back onto the aircraft more quickly, so aircraft are back in service sooner.”
“Aircraft are being repainted and/or the livery changed for a variety of reasons - the plane may be sold, leased to someone new, reached its required maintenance checks, or the owner just wants something different,” said Voisin. ”In the business jet world, it would not be unusual for the plane to be repainted in the five to seven-year range. As far as commercial aircraft, it is more related to the required maintenance checks and the amount it is flown.”
New products
PPG has launched several technologies in recent years, and now is working on enlarging and expanding its qualified systems portfolio. “In pretreatment, for example, we have qualified PPG RECC 3007 sprayable chrome-free pretreatment to U.S. Military Specification MIL-C-81706, Type II, Class 3, Form IV, Method A,” said Bencun. “The pretreatment is formulated without chrome as an intentionally added ingredient.”
“Our chrome-free primer technologies, including PPG Aerocron e-coat primer, are being approved by a growing number of OEMs and tier-one subcontractors,” he continued. “PPG CA7088 chrome-free integral fuel tank coating has been qualified to SAE International’s Aerospace Material Specification AMS-C-27725, Type 3, Grade 2. The coating can help protect the interior of an aircraft’s fuel tank against corrosion from fuel contaminants, such as water, saltwater, aircraft fuels, hydraulic fluids, engine oils and dilute acid solutions, as well as diethylene glycol monomethyl ether (DiEGME). It is one of the first chrome-free coatings for use in fuel tanks.”
PPG Desothane HD basecoat-clearcoat has three new AMS3095A qualifications, and one major player in the industry has approved the same version with solar heat management. Airlines often avoid using dark colors in their liveries because they can absorb solar energy that heats the interior while the plane is on the ground. With this technology, the coating reduces external aircraft skin temperatures, helping keep interior cabin temperatures cooler by five to seven degrees Fahrenheit, so airlines can use dark colors in their liveries.
Sherwin-Williams’ SKYscapes and SKYscapes GA (General Aviation) Basecoat/Clearcoat and SKYscapes Shimmer Basecoat, the special effects system from S-W continue to gain more usage within the MRO universe. They allow aviation maintenance repair facilities and their paint shops to augment production schedules and improve turnaround time. Sherwin-Williams is still seeing a need to provide traditional single-stage technology exterior coating systems such as its Jet Glo and Jet Glo Express - both polyester
urethane coatings.
AkzoNobel’s new chromate-free exterior primer, Aerodur HS 2121 was developed with and qualified at Airbus. For airlines, Aerodur HS 2121 promotes superior sustainability of the brand image and improves selective stripping of the decorative layer, enhancing rivet adhesion and reducing maintenance downtime. It was developed to meet all Airbus exterior system specifications, including the selective strippable systems. The product received its qualification from Airbus in March 2019.
“In addition, we recently qualified our Aerodur 2111, a second-generation chrome-free primer, to Boeing specification BMS 10-72,” said Griffin, The updated Qualified Products List was released in 2019 and since then, hundreds of aircraft (in OEM and MRO) have been coated with this primer.”
“We are very proud to have acquired French aerospace coatings manufacturer Mapaero in late 2019,” said Griffin. “We are currently working to merge the combined product offer and give our customers access to a broader range of products to meet their needs. The key additions to our portfolio are the Airbus-approved FR2-55 water-based interior cabin coating, the P60/F70 range of structural coatings, and a very unique touch-up kit package. This versatile new package enables the use of multi-component coatings without having to pour or mix small quantities, enabling customers to quickly and cleanly complete touch-up work.”
“Not a new product, but [importantly] is the authorization of our CELEROL WashPrimer despite REACH,” said Ossenkopf. “For a number of years now, one of the main topics in aircraft painting has been the effect of REACH and how end-users will have to adapt. In addition to developing further chromate-free coating solutions, Mankiewicz has taken up this issue and is committed to making the changeover as pleasant as possible for its customers. This is why Mankiewicz has decided to have CELEROL WashPrimer 913-21 officially authorized. This allows customers to use the product at least until 22.01.2026, giving them more time to thoroughly plan a switch to chrome-free alternatives while making sure to proceed business as usual. The authorization will help customers with their sustainability plans, letting them decide when and if they move to other systems at their own pace.”
