Green Printing and Plastic: No Longer Strange BedfellowsNovember 2008 By Jean-Marie Hershey
According to independent UV print consultant and former plastic printer Kurt Kroening, “Companies considering getting into the business of plastic printing would be well-advised to master the nuances of UV technology first, rather than risk expensive misfires.” A short list of the technical challenges associated with UV printing on plastic includes the need to adjust for a narrower window when setting the ink/water balance; the need to adapt printing profiles to compensate for the higher dot gain; and the need to control ink film thickness to promote curing.
Chemically or naturally biodegradable or compostable plastics made mostly or entirely from renewable resources represent one focus of an emerging industry intent on making products that enable users to control when and how the substrate degrades, while ensuring that the product remains viable and functional while still in use.
Technically, all bio- and petroleum-based plastics are biodegradable, meaning they can be broken down or degraded by microbes under suitable conditions; however, for all practical purposes, many degrade so slowly as to be considered non-biodegradable. What makes a given plastic “green,” therefore, is one or more of the following characteristics: (1) It is made from renewable ingredients; (2) it can be returned safely to the environment after use; and (3) it is manufactured in an environmentally friendly manner. One of the most familiar bioplastics is cellophane, a sheet material derived from cellulose plant fiber.
Print markets for these materials include single- or limited-use packaging materials, gift and phone cards and plant tags, as well as billboard and banner applications. Examples of biodegradable and recyclable plastics engineered to look and perform like their traditional counterparts include:
Ultraflex BIOflexFL is a biodegradable banner/billboard material for UV, solvent or screen printing. When exposed to conditions in a landfill (darkness, high heat, moisture and lack of oxygen), it attracts microbes that break down the PVC within three to five years. Ultraflex PolyeLite is a 100 percent recyclable front-lit polyethylene substrate used primarily for UV-printed outdoor billboards and banners.
Pace BIOGRAPH.ics is made from an extruded agri-based plastic resin for greater impact strength, heat and humidity resistance, and compostability. The substrate is said to be highly ink receptive. Pace reports success with printing, diecutting, foiling, press polishing, embossing, heat bending and thermoforming applications. Pace ABSOLVE, available in degradable sheets and rolls, is engineered to look and process like standard polyethylene, polypropylene and polystyrene. It is also recyclable.
Spartech Rejuven8 is a sheet and roll stock material produced from corn-based NatureWorks PLA (polylactide). Rejuven8 is said to offer superior thermoforming, clarity and diecutting characteristics, in addition to heat sealing and printing capabilities. The company also offers the Rejuven8Plus family of PLA Alloys. And it positions its Valiant modified high-impact polystyrene sheet product as a cost-effective, performance-enhanced alternative to PVC.
GOEX CAROM 45r recycled sheet is extruded from PVC with only ink applied. Recycled CAROM 88 PVC is targeted specifically to card manufacturers whose waste stream contains plastic and ink, as well as magnetic stripe, signature panels, lamination film and other ornamentation.
“From a printer’s perspective, most biodegradable and recyclable products currently on the market are very print-friendly,” Kroening says, although he adds this caveat: While the controlled temperatures of UV printing generally do not present a problem, certain finishing processes may selectively strain these substrates’ heat- and tear-resistance.
Originally introduced as a tree-free alternative to poor-quality recycled papers, most synthetic paper is made of a waterproof, tear-resistant, extruded polypropylene hybrid that has been surface-treated to enhance ink adhesion. Examples include Hop-Syn, Neenah Kimdura, MXM synthetic paper, Arjobex Polyart, Granwell Polylith, YUPO and GPA Specialty Substrates’ Ultra Green Film.
The first imperative for printers working with plastic is to institute a disciplined recycling program for their plastic scrap to keep it out of the landfill. In most cases, however, plastic recycling yields products suitable for nonprint utility and industrial applications.
Pace Industries credits many large users of its litho-grade polystyrene for their scrap, which is scheduled to return on trucks delivering new Pace stock. Material is then reprocessed to create a non-litho-grade product. In 2007, printers involved in Pace’s recycling program helped to divert more than 3 million pounds of high-impact polystyrene from the waste stream.
“We encourage our print customers to check with their local recyclers when considering our program,” says sales and marketing specialist Laurie Aspenson. “At different times one program may be more appropriate than another, due to price and what other materials the printer or end-user is trying to recycle.”
According to Aspenson, a common misconception among printers working with plastic relates to the availability of scrap polystyrene that can be reprocessed into print grade material. In reality, she says, the supply is extremely limited, due to careless handling and contamination issues.
While acknowledging the time, energy and marketing dollars being spent in the effort to develop so-called “green” plastics, GOEX Corp. realized that it already had access to a tremendous untapped, unfocused resource in the form of materials that previously were considered scrap. Accordingly, the plastics manufacturer has developed a so-called sustainable, “closed-loop” plastic recycling program that both avoids the landfill and returns a salable product to its customers.
GOEX promotes its “zero landfill” program as an opportunity for customers to recover and extract value from processed plastic (PVC and polystyrene) they previously regarded as useless waste. These materials can now be recycled back into a functional, printable plastic sheet that customers can reuse again and again.
According to Josh Gray, company president, “The value of a program like this is in enabling clients to reuse their processed scrap, rather than in selling scrap to a broker for 1-3 cents/pound or having it wind up in the landfill.”
Say the customer prints and processes a laminated PVC card job, collecting its makeready sheet scrap, card skeleton scrap and rejects. If that customer needs recycled material, it would send the card scrap to GOEX for reconditioning and reprocessing. GOEX inspects, grinds and washes the scrap, then extrudes it back into printable sheet that can be fully processed into a laminated card again. To ensure the scrap recycling process is sustainable, the manufacturer “sweetens” the recycled material with virgin raw material every time it is returned.
Environmental stewardship is the collective responsibility of all parties in the supply chain, from the press, substrate and consumables manufacturers, to the printer, to the consumer. When it comes to printing on plastic, the availability of recycled and biodegradable substrates, the widespread use of energy-curable technology, and the adoption of fresh approaches to waste-free processing strongly suggest that doing the right thing and turning a profit can be one in the same. PI