Tough As Nails

Synthetic papers are tough, but that’s just one of two key attributes that make them distinctive. The other is their ability to support high-quality printing. All applications in which synthetics are used take advantage of these qualities in one form or another.

Potential uses for synthetic papers include virtually any application that requires long-term durability, says Mike Mead, marketing manager for Wausau Coated Products. “Synthetic papers are chemical-resistant, ­water-resistant, tear-resistant, and generally more durable than paper.” In addition, synthetic ­papers provide an ease of printability, he says.

Paul Mitcham, director of marketing and sales support for Yupo Corporation America, concurs with this assessment saying, “YUPO [synthetic paper] is waterproof, tear-resistant, stain- and scratch-resistant, and highly durable, reproducing printed images consistently and accurately.”

John Giblin, VP of marketing for Granwell Products, mentions some of the different varieties and selection criteria to consider. “Today, there’s a wide range of coated and uncoated, biaxially-oriented, calendered, cast, and blown-film-type synthetic papers available and it’s important to choose the right synthetic paper for the application,” he says. “For example, our Polylith product line includes a wide range of monolayer, calendered, clay-filled grades and clay-coated or uncoated multi-ply, biaxially oriented coextrusions. Within these grades we can vary tensile, tear strength, opacity, smoothness, and whiteness—all geared to the specific application.”

There are a lot of variables outlined in that statement, and it doesn’t specifically mention some of the base materials that are typically used to produce synthetic papers. Common film types include high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS).

As an example of the different materials being offered, Mead points to the availability of Wausau Coated Products’ clay-coated PE, clay-coated PP, or clay-coated PE/PP combinations. “Depending on the film, these can be more or less tear-resistant and/or conformable,” he says.

While strength and durability appeal to many applications, what makes synthetics attractive is the high-quality printing that goes along with the toughness. There are many applications in consumer goods categories that use synthetics to enhance the shelf appeal of products.

As a matter of fact, Giblin says the tag and label industry is the largest segment for the synthetic market. “These include wrap-around labels, in-mold labels, tags, and a multitude of pressure-sensitive products,” he says.

In-mold labeling (IML) is a good example of what synthetic papers bring to the table. With IML, the labels are positioned on the containers at the time they are being formed (either blow-molded or injection-molded). They have to withstand the rigors of the high heat of molten plastic, without burning and without distorting. Synthetics have proven a more reliable substrate than paper.

In addition, David Hoag, national converting manager for Arjobex, says that when paper substrates are used in these applications, problems can arise in the recycling stream. The paper label must be removed from the container to allow the plastic container to be recycled. The reality is that there ends up being a certain amount of ­paper residue in post-consumer resin that inevitably causes a “leaker” when the residue burns a pinhole in the wall of a newly formed container, says Hoag.

Michael O’Connell, brand manager of Neenah Paper Inc., notes that one of his company’s strongest positions stems from the use of synthetic substrates to print variable images or bar codes. “Our proprietary coating enables end users in the labeling marketplace to employ various means of variable imaging,” he says. “These would include thermal transfer printing, dot matrix, ion deposition, and also inkjet.”

New opportunities

While synthetic papers have been making their mark in areas such as IML and outdoor tags and labels for some time, there are some newer markets that synthetic paper suppliers are looking to crack. “An emerging packaging market includes folding cartons and blister packaging due to the pilferage resistance and security features of synthetic paper, coupled with excellent graphic qualities,” says Giblin. “In addition, synthetic papers are being used as the strength ply in multi-layer bags and flexible packaging materials for many of the same reasons.”

Arjobex is actively working with customers on using synthetic papers to replace two-ply paper/PP bags. As always, this takes development work and for products such as these, one of the areas is the heat sealing of the bags at top and bottom. The challenge, says Hoag, is for bag converters and their customers to be able to achieve reliable seals at acceptable production rates.

Clint Beutelschies, VP of sales and marketing for Valeron Strength Films, notes some markets that could benefit from efforts such as these. “Chemical packaging and packaging of hazardous materials is a great fit for us,” he says. “Legislation regarding contamination and chemical spills means that higher performance packaging films will be used more and more.”

Giblin adds that food and pharmaceutical packaging are growing markets for synthetic papers. “Synthetic paper usage in the pharmaceutical field is expected to increase, especially with products that are known to have a high and expensive pilferage rate. Because of their high tear strengths, synthetic papers can reduce tampering without sacrificing graphic fidelity.”

As a final note, the use of synthetic papers could have a positive impact on sustainability concerns. “Choosing the right synthetic can also mean reducing the amount of packaging required by eliminating plies of paper, foil, etc.,” says Beutelschies. “In the case of Valeron, customers are able to significantly reduce the amount of packaging materials required by relying on the unique strength and tear resistance of the product.” pP