Green Thoughts

Catalyzed by such groundbreaking tomes as Rachel Carson’s A Silent Spring and Annie Dillard’s Pilgrim at Tinker Creek, Americans became increasingly cognizant of environmental pollution and teeming landfills during the 1960s and 1970s. The U.S. government responded by forming the Environmental Protection Agency (EPA) in 1970, and Congress subsequently passed Clean Air and Clean Water acts a few years later.

It speaks to the better part of human nature that people wish to make responsible material choices for the betterment of future generations. However, such altruistic notions must be balanced by fiscal responsibility — what right-thinking entrepreneur would purchase products detrimental to his bottom line?

Obviously, the sign industry uses scores of materials, and their recyclability and overall environmental impact varies. Metals (especially aluminum and steel), self-adhesive vinyl, rigid plastics and inkjet inks represent such materials. Thus, ST has asked several material experts to offer insights on the feasibility — or lack thereof — of incorporating recycled product into commonly used sign materials.

Also, ink experts discuss the ecological properties of solvent- and waterbased inks and their components, and how to safely use them for printing. And, two signshop managers discuss ways to effectively conserve materials.

Metals

From razor-thin, chewing-gum wrappers to castings that have supplanted iron in automotive-part applications, aluminum is one of the most versatile metals — approximately 1,000 aluminum alloys exist. According to Robin King, the Aluminum Assn.’s (Arlington, VA) public-affairs VP, aluminum is most prevalent in three markets — transportation, construction, and consumer products and packaging.

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From thinnest to thickest, aluminum is available in five grades: foil, sheet, plate, extrusion and casting. In the sign industry, sheet and plate are generally the commonly used grades. King said that construction applications, such as signage, require weight displacement.

"Building materials must be light and retain high strength to support structural weight," King said. "Steel weighs twice as much as aluminum. Therefore, aluminum can be used to create larger structures."

Aluminum, despite being the most prevalent metal in the earth’s crust, doesn’t exist free in nature. The vast majority must be extracted from bauxite.

Although bauxite won’t be depleted anytime soon, aluminum should be recycled because of its versatility and malleability (and, as stated before, less strain on the solid-waste stream).

"Aluminum itself has no memory, so scrap or reclaimed aluminum can be melted down and re-formed 100 times," King said. "Though you can create secondary aluminum from one type of alloy into another, it’s a simpler process to stay in the same or similar alloys."

King said that aluminum is no longer mined in the United States because it’s more efficient and less costly to mine in areas with lower population density (Australia has become a fertile mining ground, he noted).

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Also, recycling aluminum conserves significant energy. King noted that the electrical current required to create the molten state with primary (new) material isn’t needed for secondary (recycled) aluminum. As such, secondary production only requires 5% of the BTUs that new aluminum needs.

King said recycled and new material prices are comparable, though market demand fluctuates. Given increasing demand in the developing world — China and India being key players — more scrap material is being shipped there, which has created a moderate crunch.

David Meacham, Alcan Composites USA’s (St. Louis) architectural-product marketing manager for the central U.S. and international markets, noted that approximately 85% of the aluminum used in the company’s Alucobond® and Dibond® composite panels is recycled. Meacham said the company chose the 3105 alloy for these products because of its high recycled content.

Alucobond, which contains 0.20-in.-thick aluminum panels, is used primarily for architectural applications — though it’s sometimes used for signage — whereas Dibond contains 0.12-in.-thick metal and is expressly for signage and graphic-display use.

"Alcan has established programs that pursue recycled material, and that harvest surplus scrap for use with our signage and architectural products," he noted.

In the past three years, the price of aluminum has risen approximately 25%, Meacham noted. Contributing factors he cited for this precipitous rise include soaring fuel prices and heavy demand for natural resources in the developing world.

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Charleston Industries (Charleston, MS) produces aluminum sheet, sign blanks and channel-letter coil, as well as post-and-panel, extruded aluminum signage that ranges from 2 to 12 in. thick. For the sheet, blank and coil content, Charleston Industries uses 3105 alloy that’s 85 to 90% recycled, according to Mike Palesny, the company’s president.

For Charleston’s architectural-extrusion products, the company incorporates 6063 aluminum, which also comprises a significant amount of recycled material.

Like aluminum, steel is readily recyclable. Bill Heenan, a spokesman for the Steel Recycling Institute (Pittsburgh) and a 35-year, steel-industry veteran, said the steel-recycling rate was 71% in 2004.

"Steel lends itself to recycling because it has no ‘memory’ of its prior shape," he said. "Steel can be transferred from any application to another. And, unless it’s been used for radioactive materials, or in combination with mercury, it’s completely safe for any application."

Vinyl

Vinyl comprises two disparate forms — rigid and flexible, with rigid accounting for roughly 80% of the market. In addition to PVC, channel letters and building products, such as pipes and siding, also incorporate rigid vinyl. Flexible vinyl, a stalwart for architectural and electric signage, also has such widespread applications as wallcoverings and water hoses.

Pete Lindabery worked 41 years in various capacities for rubber, chemical and plastic companies, and currently serves as a recycling consultant to the Vinyl Institute (Arlington, VA). He said nearly 99% of all pre-consumer vinyl waste is reclaimed, while a Principia Consulting study indicates that 20 to 50 million lbs. of post-consumer waste is reclaimed.

"There’s been enough work done in this area over the last 20 years that it’s evident that there must be a large, consistent, clean material source to make recycling economically viable," Lindabery said. "The infrastructure must be in place to handle post-consumer products as they become available in a collectible form."

Reclaimed vinyl is available in three forms — flakes of reduced, reground material; a fine, pulverized powder; or reprocessed pellets that also contain additional polymers. Flakes require the least processing, and they’re therefore the cheapest.

Chuck Bules, Arlon’s (Santa Ana, CA) technical services manager, said processing materials used to produce flexible-PVC film, such as solvents and casting substrates, are recirculated through distribution units and thermal-oxidation equipment that captures heat. However, once the pressure-sensitive adhesive is applied, recycling opportunities narrow considerably.

"In small-scale trials, Arlon found that the combination of different melting temperatures of the acrylic and PVC, as well as the adhesive’s stickiness, made feeding it into the waste stream and extruding it impossible unless the adhesive was a very small part," Bules said. "The very stickiness that makes self-adhesive film work well for the signmaker prevents it from passing through chopping blades, discharge tubes and conveyors without gumming up the works."

David Grant and Craig Campbell, Oracal’s (Jacksonville, FL) respective marketing manager and screenprinting and digital-media product manager, said recycling adhesive-coated vinyl would exact more harm than benefit.

"Breaking down adhesive-coated vinyl releases harmful by-products, such as chlorine and unused plasticizers," Grant said. "If left untouched, it’s basically inert. Representatives of Greenpeace have said that it’s safer to dispose of self-adhesive vinyl than to try to recycle it."

Also, Campbell noted that, once PVC’s adhesive has been broken down, the powder created from recycled material offers insufficient strength for virtually any application.

Rigid plastics

Acrylic is manufactured through continuous or cell-cast processes, and its central ingredient is a methylmethacrylate monomer. Grant LaFontaine, Cyro Industries’ (Rockaway, NJ) technical-support manager, noted the differences between cell- and continuous-cast products.

Because continuous casting requires polymer re-melting, and flowing through narrow extruder and die passages, the product must have a lower molecular weight than cell-cast material. Typically, because production is constant, continuous-cast acrylic is made in greater volume.

The lower molecular weight and constant production of the continuous-cast products enhance recycling possibilities. LaFontaine said scrap acrylic can be ground and re-extruded several times with minimal loss of strength or light transmission.

To recycle cell-cast material, some foreign manufacturers operate machines called crackers, which heat the acrylic to more than 572° F (300° C). This breaks down the polymer chain, which converts the polymers back into monomers, or single-chain molecules, that may then be recast, re-polymerized or resold to other plastics manufacturers. LaFontaine said a primary concern is maintaining purity.

"The process of breaking down acrylic for reuse, or selling to recycling outfits, must be carefully managed, but it’s a healthy market," he said.

In contrast to acrylic, polycarbonate is manufactured in a continuous-cast process that incorporates Bisphenol A monomers that are linked into single-line, polymeric chains. LaFontaine said that polycarbonate may be recycled several times, but it loses some mechanical strength and may assume a yellowish, cloudy appearance.

Tammy Rucker, GE Advanced Materials, Specialty Film and Sheet’s (Pittsfield, MA) global product manager, said opaque-sheet resins are primarily based on the company’s Lexan® polycarbonate. Its most popular product for the sign industry is Lexan SG-410, a 10-year, sign-grade polycarbonate sheet.

She said the company incorporates some pre-consumer scrap material, and there isn’t a substantial drop-off in strength from virgin material. But, she noted that recycled material makes matching custom colors a challenge because the color and translucency may be inconsistent.

When 3-Form (Salt Lake City) founder Ray Goodson incorporated his company in 1990, it encapsulated film and wood prints within plastic sheets. Goodson had acquired five patents for the company’s resin-encapsulation technology. Roughly four years ago, Talley Goodson, Ray’s son, assumed control of the company.

The company developed the Varia™ panel system for architectural-graphic programs. The panels comprise a polyethylene-glycol (PETG) panel layered with a textured or patterned surface and Ecoresin® panel, which comprises 40% post-industrial, recycled resin. 3-Form has encapsulated some rather unusual items for custom client orders, such as bamboo or computer chips.

According to Grant Goodson, the company’s marketing manager, the panels maintain 25 ft.-lbs. of impact strength, 91% light transmission (which is roughly the equivalent of acrylic) and self-extinguishing flame resistance.

Inks

In the late 1990s, solvent-based inks were introduced, which reportedly offered prints that could last up to two years without lamination and several years with a finished print. However, the solvent-printing process emits fumes that may be harmful without proper ventilation, and the spent cartridges must be treated as hazardous materials when disposed.

As an alternative, "eco-solvent" inks, which emit less noxious fumes, were introduced roughly three years ago. UV-curable inks offer an additional alternative, though its manufacturers are continuing to refine them.

Steve Emery, the manager of OEM sales and marketing for Inkware (Meridith, NH), has been working in the ink market for eight years.

He said hard-solvent inks contain handling and waste-removal risks, whereas eco-solvent inks are regarded as presenting fewer such issues. At present, Emery said eco-solvent and conventional-solvent share approximately half of the overall inkjet in terms of liters of inks sold — he cites greater weatherability in current eco-solvent inks versus their progenitors.

Though he estimates they capture less than 5% of the current inkjet marketshare, UV-curable inks are the next evolution, Emery believes. The inks set through light exposure — flash lamps commonly cure the inks. From a safety standpoint, Emery noted that they emit no VOCs.

Roland DGA Corporation (Irvine, CA) sells proprietary ink formulations for their aqueous and eco-solvent printers. Marketing VP Brian McLeod noted that Roland DG, Roland DGA’s Japanese parent company, opted to offer eco-solvent printing options.

"Hot solvents require very diligent handling and incur substantial charges for freight and disposal, as well as significant fines for mishandling," he said. "It’s expensive to install ventilation systems necessary to protect your employees using hot-solvent inks."

As such, Roland DGA color-products division manager Barry Johnston said that only large signshops could afford to incorporate conventional solvent inks and the necessary safeguards required to enjoy their excellent performance and color gamut. Thus, he noted, eco-solvent inks opened the opportunity for smaller shops to use solvent inks on uncoated substrates while only making a minor ink-adhesion sacrifice.

"Over time, the ink chemistry and pigments have improved, and the ability to print on a wider variety of substrates has grown," Johnston said.

McLeod added, "There will always be a market for hot solvents; they print very well on PVC. But, with eco-solvents, you can also print on photo-glossy papers and canvas, which increases the repertoire for a smaller shop."

Johnston said the air within an enclosed, conventional-solvent printing area needs to be filtered using a hard-pipe, take-up system. For optimal VOC removal, he added that air must be extracted from under the print hood and cleaned before it’s recirculated.

The company unveiled its newest eco-solvent ink, Eco-Sol™ Max, in late August. According to McLeod, the nearly odorless inks are immediately dry after printing and offer a wider color gamut and improved scratch resistance.

According to the ink’s Material Safety Data Sheet (MSDS), it contains 55 to 65% diethylene-glycol-diethyl-ether as its primary solvent, as well as 10 to 20% of gamma-butylrolactone and tetraethylene glycol dimethyl ether and 5% or less tetraethylene glycol monobutyl ether. The ink is less flammable than conventional-solvent inks; it carries a flashpoint of 160° F.

For safe handling, the MSDS sheet prescribes a well-ventilated room and electrically conductive protective gear. Oxidizing and explosive material should be kept clear from the printing area.

The shop perspective

Being on the demand, rather than supply, end of the equation, signshops have limited — at most — control over the contents of the products they use. However, shops can bolster their inventory and save money while preventing waste.

Mike McClure, the senior project manager for Arrow Sign Co. (Oakland), said the company’s most common reuse procedure is to disassemble and restock sign cabinets from defunct or moving businesses.

"If someone wants an inexpensive sign, all we have to do is relamp and reballast an existing cabinet," he explained. "And, it’s also standard practice for us to reuse piping from pylon signs. It doesn’t make any sense to let it go to waste."

Also, McClure noted that the company has used Matthews low-VOC paints for several years without customer complaints, and it utilizes a comprehensive recycling program. In addition to standard industrial-waste materials, he noted the company recycles electronic equipment, which, although it only represents approximately 2% of the solid-waste stream, has become potentially hazardous when relegated to a landfill because of its metal content, such as arsenic and cadmium.

Charlie Stroud, Arrow’s senior designer, said the company would consider using more recycled materials if they were available on the market. The company incorporates 3-Form’s panels for certain architectural applications, but he notes their expense and somewhat limited UV stability precludes widespread use.

Steve Ashton, operations manager for Signage Systems Inc. (Mississauga, Ontario, Canada), noted the company recirculates components whenever possible, including aluminum equipment, such as lightboxes. Occasionally, plastic faces can be stripped and reused, though he noted consistent UV exposure usually makes this prohibitive. In addition to typical scrap, Signage Systems has contracted a company in neighboring Cambridge to remove and recycle fluorescent lamps. Roland DGA Corporation