MARKET REVIEW: Plastic Closures

Keeping a Lid On It
Options Keep Expanding for Customized Plastic Closures

By Carro Ford Weston

A value-added ergonomic innovation in cap design by Silgan is building Ocean Spray’s brand strength. (Courtesy of Ocean Spray Cranberries, Inc.)

Most people come across plastic closures in a dozen or more products every day without giving them much thought. In fact, some consumers still look negatively on anything “plastic,” but such purists would find their world a trifle more inconvenient and a lot more messy without these unsung little wonders of packaging.

Plastic closures are gaining ground in packaging for a number of reasons. They can be leak proof and break proof, and they offer ease of use both in removal from the bottle and in dispensing the contents. They are typically easier to open than their metal counterparts, and aesthetically, plastic closures offer opportunities for unique looks that metal closures can’t match.

Compared to other materials, another major advantage of plastic closures is design flexibility—everything from tamper-resistant bands to the hinge action of a flip-top. Cost is also very competitive, even with today’s high resin prices. The ability to introduce a variety of colors and a variety of finishes gives marketers many more options compared to alternatives.

As plastic closures acquire new features and production becomes more refined, markets for these products are expanding. As more packages move from metal and glass to various forms of plastic, a plastic closure is often required. They have penetrated all segments—from soft drinks and beer to hot fill food to antiseptic products.

The director of product development for Silgan Closures, Bill Thomas, won’t deny the numbers. Silgan Closures is a leading manufacturer metal, plastic, and composite closures for the vacuum packed foods market in North America. “For the vacuum closure market, the split of metal to plastic closures for 2000 was 66/34, with plastic growing to over 60 percent by 2005,” says Thomas. For the hot fill beverage market, plastic closures accounted for 56 percent of the usage in 2000, growing to almost 80 percent by 2005.”

The transition to plastic is driven also by strong consumer preferences for products that are lightweight, shatter-resistant, and easier to open. Safety is a concern, and child-resistant closures are required for more and more products such as petroleum distillates and other hazardous products—even baby oil.

The food market is the latest segment to adopt innovative plastic closures, although some would say it has lagged behind the beverage crowd. Many products historically presented in non-dispensing packages—like ketchup, mustard, jelly, peanut butter, and mayonnaise—now come in squeezable dispensing containers with plastic dispensing closures.

Stocking good looks

New developments in manufacturing, styling and usability keep the plastics industry fresh. Soft-touch materials, vivid colors, hot stamping, and the use of valves are some of the innovations being incorporated into closure design. Shapes are also very appealing to package designers, such as ovals of varying sizes, rectangles, and closures with tapered sides.

“Fun colors are popular, especially in the cosmetics field,” offers Peggy Wilson, director of sales for Qosmedix, a division of Qosina Corp. Qosmedix serves the cosmetics, fragrance, and pharmacy fields with plastic closures and containers suitable for packaging and product sampling. “Our broad selection of stock items allows people to choose colors right for their product and brand.” Qosmedix recently introduced flip-top caps small enough for 1.5-ml sample bottles.

Dove Launches Hair Care Line With Inverted and ‘Normal-End-Up’ Bottles Unilever views its Dove brand as one of the key brands that can help the company extend its global growth. (A profile of Unilever package design strategies starts on page 8.) Unilever asked FutureBrand, a global strategic design firm, to help it transition the strong Dove “bar soap” brand into the Dove “hair care” brand. FutureBrand’s task was to create a worldwide packaging solution that would secure an immediate position in the competitive hair care category. FutureBrand was able to take the strengths of the existing Dove brand directly into the hair care market, carrying over Dove’s reputation for quality and for “moisturizing.” Dove’s iconic oval bar soap shape translated into a plastic bottle not only successfully recalled the bar shape, the bottle shape also facilitates high-speed production. The fluid, curved lines, the silky, pearlescent bottle material, and the translucent, deep color closures all reinforce the brand’s luxurious moisturizing benefits. Dove’s matching set of conditioner and shampoo bottles features plastic closures by Seaquist.

Another popular aesthetic technique is bi-injection manufacturing, allowing two different colors and materials in the same one-piece closure. The use of bi-injection closures is helping differentiate major brands on the shelf, as Randy Hobson, sales and marketing vice president for the closure division of Berry Plastics, points out. “In the shampoo market, look at P&G’s Pantene, Unilever and Dove, and Loreal’s Fructis. You’ll see this technology continue to proliferate in the personal care markets,” he declares. Berry is a relatively new player in the closure market, with lines of continuous thread, dispensing, and child-resistant products.

Silgan Closures recently introduced a uniquely shaped 43-mm closure on 64-oz. Ocean Spray beverages, signaling the beginning of “custom” closures in the vacuum holding market. Silgan—formerly, and appropriately, White Cap—was the inventor of the first all-plastic vacuum holding closure in 1986. This was also a 43-mm device, and the first products for it was 64-oz. hot fillable packaging for Gatorade and Ocean Spray Cranberry-based beverages.

Now Silgan’s latest twist for Ocean Spray uses a 43-mm VOS Plasti-Twist injection-molded closure incorporating a patented design for improved grip-ability exclusively for Ocean Spray. “From 1986 until now, all plastic closures on hot fill products have been round with similar knurling designs,” Thomas explains. “The new closure for Ocean Spray uses a unique shape for easier gripping while at the same time building an icon design for Ocean Spray products.”

There has been little change in the composition of plastic closures. Polypropylene remains the standard material. “With cost pressures, you are seeing more cosmetic companies looking at more standard resins such as polypropylene or polyethylene, instead of higher cost, engineered resins for closures,” says Hobson. Silgan’s Thomas agrees: “All-plastic closures for hot fill products are typically made from polypropylene, so I don’t see that changing in the foreseeable future. You may see more use of plastic and metal composites to take advantages of both the plastic look and the metal graphics and seal detection capabilities.”

However, Nancy Kane, marketing coordinator for Crown Zeller USA, a leader in the design and production of plastic dispensing closures and systems, points out there is some room for customization. “Softer materials are making their way as more of a cosmetic feature on a non-functioning part of the closure,” explains Kane.

Some custom plastic closures quickly become stock items, like the smooth European-style “Crescent” cap from CCL.

No muss, no fuss

Ease of use is a major driver behind many product-packaging innovations, and likewise, the movement to dispensing closures from standard threaded varieties is driven by consumer preference. Given the choice, most of us would rather not fool with a screw-off lid on our bottled water, shampoo, or ketchup. Crown Zeller is known for the hinge technology incorporated into all of its closures, which allows users to fully open a package and easily dispense its contents—one-handed, if necessary—while keeping the cap conveniently within reach.

“Easy to use” also means no mess to clean up, so dripless valves, primarily in food packaging, are becoming popular. Like the SimpliSqueeze cap from Seaquist Closures, made popular by the Heinz and Hunt’s ketchup bottles, these caps incorporate a silicon valve, which allows non-drip, controlled dispensing. Non-drip also drives the trend toward more inverted packages, which in turn require stable, flat caps. Inverted packages of all kinds—with or without valves—are gaining share in food and personal care markets. Consumers appreciate the convenience of storage as well as the ability to easily extract the product from these containers without having to stand them precariously on end in the shower or fridge.

Crown’s new “I-Squeeze” closure, with a non-drip valve, is targeted to this market. In addition to food and beverage, the I-Squeeze is able to dispense thicker products like toothpaste in novelty shapes. Qosmedix recently introduced a line of flexible flip-top “Tottles” that allow a variey of packaging styles and shapes to stand on their heads. For the amenities, travel, and sampling markets, Crown Zeller recently introduced several small-size flat-top flip-open dispensing closures with the same dimensions as existing non-dispensing closures.

Molding for economy

Manufacturing professionals are constantly on the lookout for better, faster ways to make whatever they produce, and that includes plastic closures. Both injection and compression technology continue to be used for hot fill closures, while higher cavitation injection molding presses now challenge compression molding for lower cost output.

Bi-injection is not just about aesthetic appeal—it also offers advantages for manufacturing efficiency. When two different resins or two different colors of resin are injected at the same time into a single mold, they produce a one-piece two-color—or two-material—closure. The benefits are elimination of assembly steps, as well as a more interesting package. “Assembly for several of our closures can also be done in-line, speeding up the time to produce a complete part,” notes Kane.

Cost pressures are driving molders toward larger tooling in commodity closures. The other major pressure is speed to market. “Consumer goods companies want to cut their product introduction cycle in half, and much of that pressure ends up on the packaging supplier,” says Hobson. “North American tool builders are working hard to meet this challenge and stop molders from going outside the U.S. for tooling.”

That hasn’t stopped companies from going elsewhere for ideas and influences. The Crescent and Ellipse screw-on and push-on dispensing closures offered by CCL Dispensing Systems are now available as stock items, giving marketers the advantage of custom-look European design without incurring additional costs for designs, molds, and production. “Also, more consumer goods companies are looking at brands more globally—such as Axe from Unilever,” Hobson adds. “This has accelerated the pace at which the U.S. market is replicating European packaging and closure trends.”

Considering the variety of packaging that uses plastic closures, it might seem there would be a lot of customization. Actually, customization is not that widespread due to the expense and difficulty of retooling manufacturing equipment, molds, and processes. Customization involves trade-offs, such as sporting a unique look at the expense of manufacturing economy. Instead, some vendors offer broad product lines suited to a variety of customer needs.

Berlin Packaging, for example, offers a seemingly endless variety of plastic closures to go along with their seemingly endless variety of plastic containers. Berlin sources in excess of eight billion containers and closures annually, so economy of scale could be one reason they are able to stock such a wide range of styles affordably.

Other companies approach the market with designs that differentiate themselves yet are interchangeable with a wide variety of packaging. “Our stock closures can easily be incorporated onto existing packaging with the appropriate bottle finish,” explains Crown Zeller’s Kane. “When developing new closures for customers we can work with them to minimize changes to filling or capping machinery.” With the market turning to more plastic closures each year, customization has become a matter of degree, a consideration of how much to invest in bringing aesthetics, functionality, and convenience to the consumer.