Sounding Boards

Tag/paperboard suppliers and converters air game plans for managing printing differences among surfaces, calipers and chemistries.

By Susan Friedman

Put the same tag or paperboard substrate through several different print processes, and the only thing that's likely to change is image quality. The most pronounced differences in the performance of these substrates on-press arise across the categories of surface, thickness and formulation.

Coatings, synthetics lead tag issues

A high degree of performance diversity can be found between coated anduncoated tag stocks, explains Glen Payton, Product Manager, Fraser Papers. "Coated tag stocks are best used for very high quality four-color process printing with line screens over 175," he says. "Conversely, uncoated papers come in a much wider variety of finishes, visual textures and colors, which provide a unique interaction of ink and paper that can't necessarily be duplicated with slick, white coated paper. In many cases, an ink station can be eliminated from the press run by proper use of colored uncoated paper. On the whole, uncoated papers can help the print budget in paper and press costs."

A critical difference Payton identifies for offset printing of coated vs. uncoated tags is dot gain, as ink absorption is higher on uncoated stocks. "Dot gain of 10 percent to 15 percent typically limits line screens to 175," he notes, "though proper design and press operation can yield excellent, on-budget results."

According to Daryl Evans, GM at Mafcote-Wabash Paper Coatings, a separate set of printing disparities may present themselves in the movement away from traditional paper tags toward synthetic materials that offer increased strength and resistance. Synthetic substrates tend to stretch, inhibiting clean cutting and punching operations. Other potential problem areas include tracking and registration.

Mafcote-Wabash addresses further synthetic needs with Typar Tag, a 100 percent spunbonded, polypropylene stock Evans describes as comparable to DuPont Tyvek in strength and moisture resistance, but more economical. Corona treated for enhanced printability, 10 pt. Typar Tag is available in coated or uncoated white.

Smoothing board's rough spots

On the paperboard side, converters emphasize their energies are primarily devoted to banishing board thickness issues, ensuring consistent converted results, and squeezing more mileage out of uncoated board stocks.

According to Marketing Manager Pat McGee, Graphic Packaging leaps the thickness barrier with Composipac, a patented process in which the company reverse-prints on film, vacuum metallizes behind the inks, and then laminates the film to paperboard. Lamination eliminates board thickness issues, and has led to successful replacement of preprinted corrugated material. Composipac allows less expensive base material to be used, while still achieving superior graphics. The process can also integrate more packaging functionality, such as moisture and vapor barriers.

At Fibre Container's Folding Carton Division, General Manager Tom Wynne credits advanced sheet transfer technology on its MAN Roland 700 offset presses with a recent heavier substrate

handling success. Though designed to run board up to 40 pt., the MAN Roland was able to print a 42 pt. F flute, normally done flexo, without crushing the corrugated material. Its flexibility enabled Fibre Container to provide a matching gloss on one customer's corrugated and folding carton packages.

Whether running SBS, SUS or clay-coated newsback, Wynne employs an overall strategy to "stick with better paper, and use the sames ones over and over to provide customers with consistency." Higher quality paperboard remains stable from process to process, and pays for itself by allowing presses to run faster, he advises, citing the MAN Roland presses' ability to reach speeds of 15,000 sph.

Corrugated preprinter Inland Paperboard and Packaging solved persistent score cracking issues with Temple Premium, a clay-coated SBS developed by parent company Temple-Inland with higher soft wood content for liner grades. Mixes with higher hard wood content can cause cracking in triple-layer corrugated packages, explains Graphic Resource Center GM Terry Ong, but typically don't cause problems for single-layer folding cartons. Score cracking can also result if a board's moisture profile is below 6 percent, Ong notes. In addition, drier board will absorb water-based inks like a sponge, and expand.

For Climax Packaging, flexo has proved most forgiving for accommodating a wide range of substrates in an array of calipers, due to the pressure control it affords via anilox rolls, notes Liz Hirschey, marketing manager. Climax's flexo line work graces everything from SBS to uncoated recycled chip board, with the goal of solid, heavy ink coverage that looks even.

One of the biggest printing challenges for paperboard Hirschey cites is the current shortage of uncoated stocks which can achieve appealing looks while still providing on-par press performance. For a smoother surface, printers can seal uncoated material with a primer, or laminate to it, but then face increased production costs, she adds.