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Paper Substrates



Familiar stock is continually re-engineered to meet changing package trends.



Published July 11, 2005
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Paper Substrates

From a converter perspective, selecting the proper paper label stock from a sea of endless rolls can be a dizzying task. It’s a game of chance — a balancing act. If careful attention is not paid to substrate characteristics, the finished product might bring an unpleasant surprise.

According to suppliers, some of the most important characteristics to be considered are paper strength and stiffness, ink receptivity, base sheet uniformity, smoothness, brilliance, whiteness, opacity, and gloss levels. With continuing demands for lower costs, downgauging has become another factor, bringing even more characteristics to the table. Digital printing technologies, including thermal transfer, dot matrix, laser and inkjet, carry their own lists of demands as well.


It all depends
Just as each paper has its own characteristics, so each label print job will require a paper stock that meets a variety of requirements, depending on the end use of the product that the label will adorn. Ray Mackura, technical support manager for the product identification division of Avery Dennison Fasson Roll North America, Painesville, Ohio, lists a few examples. The first factor, he says, is the application being considered, such as stiffness, dispensability, strength, basis weight and ink adhesion. Next is the “look” that the converter and the packaging customer are trying to achieve; this can include a combination of gloss level, smoothness, brightness, color, opacity and ink holdout for color matching. A final consideration, he adds, is any secondary print methods being used, such as thermal, laser, inkjet and date stamping.

Mike Saul, marketing manager of Technicote, Miamisburg, Ohio, agrees that customer expectations are dependent on the type of job being executed. “For a high-end, eight-color process job, the customer may look for a paper that can achieve eye-popping graphic appeal, such as a wet gloss look or a non-cast coated high gloss paper,” he says. “The pharmaceutical industry holds different requirements, like flexibility, less stiffness, lower basis weights, dot matrix, laser and thermal transfer printability, as well as ballpoint pen smudge proof characteristics,” he adds.

Aside from these factors, however, customer demands have changed along with improvements in print quality, converting speeds and label application speeds. “An emphasis is shifting toward higher process line screens, crisper line art, brighter, blue-white paper shades, with no loss in strength or the other physical properties necessary at high line speeds,” says Mackura.

Matti Laakso, sales manager, Cham-Tenero Paper Mills, Switzerland, adds runnability, exact roll length and consistent whiteness to the list of changing customer demands. Whiteness, which can vary across a single roll of stock, can affect the visual spectrum that can be achieved with the base substrate.

Dust is another issue. “It’s important that paper arrives to us with a stable finish that contains zero dust. The product must also retain this feature throughout our slitting, printing and diecutting processes,” says Tom Michalsen, manager of media products, Weber Marking Systems, Arlington Heights, Ill. “Blue-white properties seem preferable these days,” Michalsen adds.

According to many paper stock suppliers, packaging customers are looking for the most durable “system friendly” sheets. Unfortunately, cost has become a much greater factor compared to previous years. But as one supplier says, you’ll get what you pay for.

One way suppliers and distributors have cut back on cost is through downgauging. The change in paper weight certainly reflects well in the costs margin, but with it come the challenges faced in dispensing the labels. Auto-labelers have been able to compensate and adjust their machines to dispense 55-pound and 43-pound facers, where 60-pound and 50-pound were once used before.

Another way to combat the dispensing issue is to achieve a lower release on the liner, so that the label will peel off much more easily.

Aside from dispensing issues, Mackura adds paper strength characteristics and opacity to the list of challenges which accompany downgauging. “Understanding the actual properties necessary for success in the application is a key ingredient to overcoming hurdles in these areas,” he says. “Paper formation and paper coatings can overcome some of the challenges, but converters working as a team with industry suppliers — such as substrate, ink, press, dispensing equipment, and other suppliers — can offer innovative solutions to packaging designers.”


Challenging market segments
From pharmaceutical and industrial to the aesthetically pleasing health and beauty markets, each segment presents its own distinct challenge.

The pharmaceutical industry demands an above average face sheet, which, combined with a high shear, “no-wing up” type adhesive, will provide the end user with an effective store level label.

“The pharmaceutical industry is the most demanding,” says Michalsen of Weber Marking Systems. “Most of our applications involve flexo printing and variable thermal transfer printing. Font sizes are small and legibility is paramount.” As a result, an extremely smooth substrate surface is required for improved ink release.

“Balancing excellent paper strength characteristics with smoother, glossier sheets for printing is the key to enabling the roll label converter to compete with and overtake traditional offset and rotogravure printed applications,” adds Mackura of Avery Dennison.

Health and beauty demands include a face stock that is moisture resistant, ultra smooth, high in gloss and can print high-end graphics. The bottles may also require a clear-on-clear label, making adhesive and silicone coverage important. For this particular market, Ahlstrom Paper Group, Atlanta, Ga., offers its Silca Clear silicone base paper, used to line plastic transparent labels for the no-label look.

The industrial market focuses on a more durable and longer lasting substrate. “Substrates for industrial applications must be able to withstand extremely high and low temperatures and resist certain outdoor requirements, such as fading and yellowing,” says Saul of Technicote.

In this particular market, synthetic papers are making inroads with its high strength and durability.


Synthetics
End-user price pressure has driven the white and clear film market closer to paper prices. Synthetics are the best to use for aesthetics, shelf appeal and overall effect.

Suppliers provide their outlook on this emerging substrate. “Synthetic paper substrates usually service specific application requirements, and have not impacted the overall paper use in a positive or negative way,” says Mackura.

Laakso, of Cham Tenero, says synthetics have experienced high growth, but from a small market share. He adds that he expects synthetic to gain more share in the next few years.

“Synthetics are invading the paper market, but only in certain segments that require durability and strength. One area is the industrial industry, which requires a significant amount of durability,” says Saul of Technicote. “Synthetics have not yet penetrated high-end markets, such as health and beauty, but are making their way into the pharmaceutical area,” he adds.

Michalsen provides a different view. “Synthetics continue to grow at double-digit rates. They have a greater perceived value among end users, and replace paper in many conformable, medium durability applications,” he says.

“A tidal wave of change is occurring in the synthetic paper market, which is to the benefit of tag and label converters and their customers,” says John Giblin, marketing director at Granwell Products, West Caldwell, N.J., which produces Polylith synthetic papers. “New suppliers are changing the face of the market, providing more competitive pricing as well as new products with a wider range of grades, finishes and strengths.”

Jeff Morgan, vice president of marketing and sales for Yupo Corporation, Chesapeake, Va., discusses the growth of synthetic paper in the commercial printing industry. “Value-added durability characteristics, such as resistance to water, tearing and scuffing, make it ideal for applications that include maps, menus, manuals, point-of-purchase displays, posters, books and tags,” he says.

“ ‘Yupo’ is an ultra smooth, bright white synthetic paper that prints remarkably similar to traditional paper,” says Morgan. “Aside from holding razor sharp images, the paper accepts value-added finishing applications that include foil stamping, diecutting, embossing and binding.”

Also involved in the synthetic market is Arjobex, Charlotte, N.C., with its Polyart product.


Adhesives, coatings and release liners
Understanding the requirements of a job also means selecting the correct adhesive and liner combination to obtain increased press speeds. “There have been improvements in hot melt chemistry in recent years that have enabled a finer process of extruding adhesive to ensure a more consistent, friendlier-to-convert product, at higher speeds,” says Mackura of Avery Dennison.

“Additionally, improvements in paper coatings chemistry and increased knowledge of the interaction between these coatings and ink chemistry have led to products that work across more print processes than before,” says Mackura. “More focus on training within the industry in recent years has opened up partnerships and discussions that have led to higher quality and improved press output.”

With acrylic emulsion adhesives, higher press speeds are attainable. Acrylics also provide a suitable amount of repositionability time if the product is mislabeled. Acrylic adhesive are also easier to diecut than rubber based adhesives.

Laakso of Cham-Tenero says a major advancement on the release liner front are liners that offer higher silicone cure speeds and more uniform silicone holdout.

In this area, Ahlstrom Paper Group offers its glassine liners for high speed silicone coating. For laser copy and self adhesive vinyl laminates, Ahlstrom Paper adds a line of clay coated liners to its offering.

Saul of Technicote says consistent caliper has been addressed more in the release liner market to help avoid matrix breaks.

The emergence of thermal transfer, direct thermal, inkjet and laser printers has given rise to different levels of characteristics of paper substrates, and suppliers are scrambling to keep up with the evolving demands. With the rising popularity of the Internet, the bar code market in particular (which utilizes many of these printing technologies) has experienced significant growth, says Andy Woodward, industry manager, Maratech International, Channeled Resources, Chicago. “People are sending more and more packages that require bar code tracking. Five or six labels can be produced when one item is purchased over the Internet,” he says.

As this market continues to develop, paper suppliers have found themselves focusing on products for non-traditional label printers. Some of these specific characteristics include higher speeds for thermal transfer printers and more ink receptive substrates for inkjet printers.

Inkjet printable paper requires the ability to absorb the ink with excellent resolution, says John Guzzo, president of Polykote, Warminster, Pa. The demand for glossy inkjet printable papers to achieve a photo quality look, is another trend, he adds.

Shelf presence
“More and more of an ever-present challenge to package and label designers is creating powerful shelf presence for their product,” says Tina Anagnostis of Proma Technologies, Franklin, Mass. “Today a successful label not only needs to convey the details of the product, but must also have the ability to cut through the clutter on store shelves and capture the attention of the busy consumer.”

Holographic paper is one way end users have provided themselves with an advantage in this competitive marketplace. In the dazzling holographic realm Proma Technologies offers its eye catching “HoloPrism” product. The company recently worked closely with Pennzoil to create a paper label that would provide the product with an advantage at the point of sale.

Anagnostis describes the product. “The label features a holographic sphere accentuated with the yellow and black Pennzoil logo applied to silver gray bottles. On busy store shelves, the package provides movement, creating an eye catching effect that calls attention to the product.”

Another developing area is a rise in use of UV lacquers and overlaminates to make up for the growing demand of lower grade papers, says Guzzo of Polykote. In the past, more expensive high-gloss paper was in demand, but now as customers have recognized the more affordable overlaminate alternatives, this demand has taken a new turn toward lower grade papers, he says.

Mackura of Avery Dennison points to another developing trend. “A consistent question being asked is, ‘How can we consolidate inventory and still compete in the higher-end graphics part of the market?’ The increase of industry supplier-to-supplier partnerships is growing and providing opportunities for innovation through working together to solve issues, instead of looking at an issue from one perspective,” he says.

“This results in helping the converters and their customers by bringing a team effort into the game, from substrate through dispensing/filling line suppliers and everyone in between. It has acted like a springboard toward gaining new and growing business in the narrow web market,” he adds.



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