That’s a Wrap

A look at lamination as a finishing option for fenestration
David Harris
July 30, 2019
COLUMN : In the Trenches | Materials & Components


Bronze remains a dominant residential color, as do subtle earth tones like clay and almond. (Image courtesy of the author.)

The window industry continues to see an increasing request for colors. Today’s consumers demand more color and design options, inside and out, both for new construction and especially in the replacement market. Homeowners want the chance to complement or accent the design of their home with more window options.

Current trends show bronze remains a dominant residential color, as are subtle earth tones like clay and almond. The current big trend is for statement colors like black and gray. This means black, bronze and other solids are making their way inside, too.

“Color has been around for a long time in Europe; it’s grown really well in much of the U.S. and Canada,” Jamey Rentfrow, owner and president of Stealth Finishing, reports. “More recently, that demand has really moved into the west and Southwest. The use of color will continue to increase—it’s here to stay.”

And, don’t forget the woodgrains. In the past, the industry was in a bit of a rut with very dated-looking older woodgrain patterns. They had a shiny appearance and the print quality was less than ideal. All of that has changed. There are new interior woodgrains that boast very realistic print design and a beautiful soft surface finish.

Typically, the techniques for adding color or design to profiles include colored profiles, either solid color extrusions or by means of cap stock, painting or applying laminate films. Over the past few years, laminates have become an increasingly more interesting and important means for adding color. New films also offer scratch-resistant coatings and stand up to everyday challenges, maintaining their appearance year after year.

“Take a look around the industry and you will see more and more lamination,” says Rentfrow. “It is really growing, and we fully expect it will continue.”

How it’s done 

Profile wrapping or lamination is always done on full-length profiles. Wrapping is done on a linear processing machine called a profile wrapper. It is a stand-alone operation, separate from the extrusion process.

The laminate film is supplied in a mother roll. First, that roll is cut on a machine called a rewind slitter into precise narrow width rolls to match what is needed for the profile. Next, the slit roll is put on the unwinding station of the wrapper. Profiles are fed into the machine end-to-end. In the first station, profiles are cleaned of any contaminates so the adhesive will bond properly to them. Heat is then applied to warm the part.

The film passes in front of a glue application unit and hot melt adhesive is applied to the back of it. The film travels down the machine and meets up with the profile. Next, a series of tooling rollers precisely form the film into the geometry of the profile. The profiles are separated, inspected and placed in a rack. Once the glue is fully cured, the parts can be cut, welded and processed the same as plain white profiles.

Many manufacturers ask whether the film will peel off in the field after time or in difficult weather conditions. The answer is no, it will not. The adhesive used in the process is a specific polyurethane reactive hot melt (PUR). A PUR is processed similarly to a traditional hot melt but, during the process, the PUR actually pulls humidity from the air. That moisture causes a chemical crosslink within the glue; when fully cured, it cannot be reactivated. This means it is a permanent bond. That resulting bond is ideal for all weather conditions, from extreme hot to cold and very humid to very dry.

For assurance, wrapped parts are tested against two AAMA specifications. They include a peel test to confirm bond integrity and a boil test where the parts are submerged in boiling water for one hour. After these tests, no separation of the film from the profile will occur. And, the same machine and process that applies exterior films can also be used for interior products.

Editor’s note: The author prepared a case study based on Rentfrow’s foray into starting a finishing business. Read about his experience with different color technologies.

David Harris is product manager for American Renolit Corp., maker of films for fenestration profiles, including Exofol FX, which carries a 20-year warranty. He can be reached at david.harris@renolit.com or 616/554-2230.