At any design show there are sure to be groups of professionals gathered around an exhibit, staring longingly at the panels. Their gazes penetrate, looking deep within the material, in fact seeing right through it… because it’s translucent. Material enthusiasts are intrigued by architectural resin panels, which can be imbedded with a seemingly endless variety of decorative inclusions (grass, leaves, shells, metal shavings etc.) and still allow light to pass through. Though the technology has been available since 1994, it is only in the last ten years that translucent resin panels have really made their mark in the design world, first in commercial applications and now increasingly in residential projects. Considering that they are both a panel product that can generally be processed on standard equipment, and a decorative surfacing material that is often specified in conjunction with other engineered materials, it is worthwhile to take a look at the fact behind the fashion.

Resin panels can be divided into two categories: decorative-quality panels and architecturalquality panels. Decorative panels are used primarily as accent work and can be made from a variety of materials. Architectural panels are similar, but meet stricter requirements for structural integrity, impact resistance and fire ratings. There are two primary resins used to make architectural resin panels, acrylic (PMMA) and copolymer (PETG). This story will focus primarily on where PETG panels come from and how they are brought to market.

TECHNICAL CHEMISTRY ALERT

Poly Ethylene Terephthalate Hexane Diglycol (PETG), is a clear amorphous thermoplastic that can be injection molded or sheet extruded and can be colored during processing. For architectural resin panels, pure PET is modified by adding cyclohexane dimethanol (CHDM) to the polymer backbone in place of ethylene glycol. Since this building block is much larger (six additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighboring chains the way an ethylene glycol unit would. This interferes with crystallization, which lowers the polymer’s melting temperature and makes the end product clear. PETG tests out at 18 times more impact resistant than unmodified acrylic and three to five times more resilient than modified PMMA. Compared with glass, PETG is 40 times more impact resistant.

Like all plastics, PETG begins life as a chemical mixture that is initially extruded and chopped into small pellets for ease of transport and storage. The pellets are then sold to extruding companies that extrude the pellets into many different forms, including sheets. PETG sheets are sold to laminators, who sandwich a decorative layer between two panels and press it under heat and pressure. The process is referred to as Encapsulated Image Layer Technology or EILT, and is proprietary from the formulation of the resin through finished product.

THE PLAYERS

Eastman Chemical Co., of Kingsport, TN manufactures the PETG pellets that eventually become architectural eye candy. They have an exclusive agreement in North America with Spartech Corp., located in St. Louis, to extrude and distribute the clear PETG sheet goods under the brand name Spectar resin. Spectar is Eastman Chemical’s fastest-growing specialty plastic.

There are four companies in North America licensed to use the EILT process, 3Form and Veritas (both owned by Hunter Douglas), Lumicor and Chrysalis HD. These companies each carry several product lines, but the PETG architectural resin panels produced by these laminators all share common parentage. In fact, the PETG products are identical. “The difference comes down to design and method of going to market,” says Joanna Jorgensen, CEO of Duraglass, the company that manufactures Chrysalis HD.

DESIGN AND MARKET

There is a lot to like about architectural resin panels with embedded inclusions. For one, they are pretty. Architects and designers like them because they are a wonderful material for working with light. Botanical inclusions help to “bring the outside in,” though Jorgensen cautions that there is enough empirical data now available to conclude that botanicals that are not absolutely dried prior to lamination (which is difficult to do) have a tendency to delaminate after about three years. Eric Kurtz, product manager for Lumicor adds that the PETG panels have a great green story. “The standard PETG panels contain 40 percent post industrial recycled material, and specialty panels can have a much higher percentage than that,” says Kurtz. “Resin panels are also 100 percent recyclable.” PETG resin panels are class “A” fire rated, Greenguard certified for indoor air quality and can qualify for several LEED credits.

PETG architectural panels typically carry a surface treatment to protect against exposure to UV rays. Left un-protected PETG will yellow over time when exposed to sunlight. Cap overlays can also be specified to increase abrasion and wear resistance and to protect against chemicals, making the panels good specifications for a variety of applications. All PETG panels also make great dry erase boards and are available in different thicknesses, though some producers charge extra for different dimensions and characteristics. Release papers can be added on top of the panel- inclusion-panel sandwich during lamination to add surface texture to the end product. PETG translucent resin panels can be thermoformed and cold bent without damage to the inclusion. Edges are fused with heat, and some finishes are “self-healing” and can be fixed with hand-held heaters or crème brulee torches on site.

Architectural resin panels are not intended for load bearing applications. They are commonly used in commercial projects such as room dividers, ceiling panels and decorative accents. To encourage residential usage, companies have created partner programs with kitchen/ bath and home storage solution companies to offer PETG resin panels as options for backsplashes, cabinet inserts and counter tops. More adventurous end users have specified the panels for flooring and exterior applications, which looks great but voids the warranty.

“The biggest difference between the companies who make PETG translucent decorative panels is the way we bring goods to market,” says Jorgensen. 3Form, Veritas and Lumicor primarily focus their efforts to selling directly to architects and designers. Chrysalis HD took a different platform and sells through distribution. The companies that sell direct have beautiful promotional material, offer lots of custom variations and tend to have big advertising budgets. Whereas selling through distribution relies on ease of access to reach the market place, with strategies including a large offering of standard designs, short lead times, and no price differential for options like panel thickness.

Clearly PETG architectural resin panels have caught the attention of architects and designers worldwide. And a better understanding of what they are, where they come from and how they come to market makes it easier to specify the right panel for the project.