What I Learned on My Summer Vacation

Posted on Friday, August 1, 2014

Well powder fans, the 2014 PC Summit is history now. It wasn’t exactly my summer vacation; however, I have lots to report on. As expected, we had a band of industry experts expounding their knowledge of the latest technical trends in our industry. And, as always, we had a throng of august technologists attending and bringing networking to an expected crescendo.

I was fortunate to emcee this event and experience firsthand the unveiling of some of the coolest innovations taking place in the finishing industry. Highlights of a few of the most innovative topics are presented below.

Non-phosphate Pretreatment

Chris Berger of Calvary Industries shared some of the latest innovations in zirconium pretreatment for aluminum and steel substrates. He explained how this technology is rapidly replacing phosphate pretreatments because they produce significantly less sludge and operate at lower temperatures, thus minimizing hazardous waste and lowering operating costs.

Zirconium-based pretreats debuted in the late 1990s, however the initial products exhibited a number of problems, including flash-rusting, complicated control testing and inconsistency across substrate types. Pretreatment scientists went to work and developed solutions to these issues. Calvary Industries, in particular, found that by modifying the zirconium material with a proprietary alternate pretreatment chemistry these shortcomings could be ameliorated. In addition, the process is much more robust and user friendly.

Chris provided a few examples where traditional iron phosphate and zinc phosphate pretreatment systems were converted to Calvary’s Advantech ™ technology and demonstrated the improved performance and lower operating costs. The most compelling case depicted the change-out of a nine stage zinc phosphate to a simpler six-stage process based on Calvary technology. The new system is less prone to flash-rusting, uses less heat, is not pH sensitive and produces essentially no scale.

Gas Catalytic Infrared (IR) Curing

Marty Sawyer, one of the principles at Trimac Industrial Systems, provided a thorough tutorial on this intriguing curing technique. Gas catalytic IR relies on the combustion of natural gas (methane) to create infrared radiation that can be used to transfer heat energy to a coated surface. This type of combustion is highly efficient because of the platinum catalyst embedded in the emitters.

Marty explained how this innovative technology uses the same technique employed in automotive exhaust systems. The process creates IR in a very efficient manner combusting nearly 100 percent of the gas and expelling only a small amount of CO2 and water. This is possible because the catalyst lowers the activation energy of combustion and therefore reduces the energy needed to create the infrared. Gas catalytic combusts methane at around 250°F compared to the traditional combustion temperature of 1200°F. In addition, this process is flameless and therefore much safer than conventional gas-fired burners.

Gas catalytic IR can replace less efficient gas convection ovens and also reduce the time to cure a powder coating. Faster cure times result in lower capital equipment costs and a significantly smaller process footprint. Another advantage of gas catalytic IR is, like other IR technologies, the majority of heat is delivered to the coating material and not the work piece. This reduces the overall energy needed to cure the coating.

Marty showed a number of examples of finishing lines that had converted to gas catalytic IR including ones running complex parts, thick/ dense parts and diverse mixtures of parts. In all cases the finisher was able to reduce operating costs, shorten process times and reduce work-in-process with this environmentally friendly technology.

Steel Quality, Pretreatment Effectiveness and Solutions for a Globally Compliant Era

A few months ago, I authored a piece titled “Don’t Blame the Powder” for corrosion and/or adhesion failures. I chided that the culprit is usually the metal pretreatment and not the coating. However Dr. David Chalk from DuBois Chemicals Inc. begs to differ. He emphatically posited that it’s typically not the pretreatment at fault but the quality of the metal substrate instead. His comprehensive explanation made a believer out of me.

Dr. Chalk talked about the evolution over the past 20 years of the steel industry. Most significant is the loss of blast furnace production operations in the Western world. He states that over 90 percent of all steel-making blast furnaces are now located in China. On the surface this doesn’t seem earthshattering news; however, this development coincides with the practice of incorporating up to 25 percent scrap metal into each batch of steel. What this does to pretreatment technologists is create a moving target for their chemistry’s performance. The highly variable carbon and alloying element contents in cold rolled steel wreak havoc on cleaning and pretreatment quality. Dr. Chalk recommends using a versatile zirconium chemistry to combat the inconsistency of steel substrates.

He also commented on the global regulatory push to restrict a number of elements useful in pretreatment technologies, including many metals and fluoride based compounds. The use of fluorine chemistry in zirconium pretreatments will quite possibly restrict the commercial use of these. A potential alternative to existing pretreatment processes is to employ strong acid based organic compounds for metal preparation prior to powder application. DuBois Chemical has developed prototype materials and has conducted successful trials on commercial finishing lines. This technology uses no metals, operates at ambient temperature and works on widely variable quality steels.

A number of other very interesting technology advancements were presented during the 2014 PC Summit. I will be reviewing many of them in the upcoming issues of Powder Coating Tough magazine. Stay tuned, powder coating fans.

Kevin Biller is technical editor of Powder Coated Tough and the president of The Powder Coating Research Group.  He can be reached at kevinbiller@yahoo.com