"From an inventory standpoint, flexible packaging is very attractive," Martin said. "You are dealing with roll-stock, not pre-made packages. Food companies can benefit from the number of choices converters have to offer."
About 18 months ago, predominantly new products were being packaged in stand-up pouches, Martin said. "The pendulum has swung; now food companies are repackaging many of their existing products in stand-up pouches."
Nabisco decided to go this route with its Ritz Snack Mix. "This product moved from a typical bag-in-box application to a stand-up, Doy-style pouch with reclosure and is working extremely well," said Kevin Migliacci, senior packaging engineer, Nabisco. "Sales of the product more than doubled just by changing the package."
Nabisco made the switch in November 1997. "We wanted consumers to perceive the product as more of a hand-to-mouth snack. The bag-in-box package is perceived as more of a cracker," Migliacci said. According to Migliacci, a package change can influence the perception of a product, particularly for products positioned between categories such as the Ritz Snack Mix. The product had an image problem because it was placed between the cracker and snack category.
Nabisco has emphasized flexible packaging for two reasons. "Barrier properties keep improving. Films are now closing the gap between plastic and metal cans or glass. Now we can get these barriers at a lower cost. Higher end flexible packaging materials are less expensive than materials such as glass," Migliacci said. The Ritz Snack Mix is packaged in a metallized oriented polypropylene film (metOPP). "This package with its sharp metallic graphics is louder than most Nabisco products. It was designed to attract more of a teen consumer and is working very well," Migliacci said.
Consumer acceptance of flexible packaging no longer is a problem. "There are very few products consumers will not accept in flexible packaging," Migliacci said. "But, there are some products consumers will most likely never accept in a flexible pouch -- such as milk. Products with a long history of being packaged in one style have a difficult transition."
Reclosability is the number one convenience consumers want, especially in the larger package sizes, Migliacci said. The fear is that a closure device, such as a zipper, could hinder consumption rates so it is important they are easy to open and close. Therefore, the type of closure chosen must be extremely familiar to consumers, Migliacci added. Zippers are well known, simple to operate and most often the closure device of choice.
"There has been a change in the dynamics. There used to be a few basic salads, a limited number of choices. Now there are greater varieties of salad mixes and exotic lettuces. We see European, Mexican and Oriental salad mixes," said Jeff Wooster, value chain manager, food and specialty packaging group, Dow Plastics (Midland, MI).
The right environment is critical for fresh-cut produce. "You need to have the right mix of barrier and breathability as well as the right gas mixture within the package to optimize shelf life," said Rimes of DuPont. "Moisture transmission, oxygen and CO2 levels must be balanced depending on the content."
These salad varieties are popular, and they are difficult to handle. "They are more tender and require careful handling by the processor. They have different respiration rates and require higher performance packaging materials," said Wooster of Dow.
But higher performance films do not always translate into higher performance on the packaging line. Dow has two new Affinity polyolefin plastomer (POP) resins, Affinity PF 1146 and PL 1888, that fit the bill for the fresh-cut market. Along with the breathability of the resins, PF 1146 and PL 1888 have improved coefficient of friction (COF) control with reduced blocking. These qualities make the film easy to handle and minimize the tradeoffs normally associated with improved machinability, such as reduced optical qualities. "Affinity resins also make strong, secure seals at lower temperatures. The seal temperatures range from 80 to 90? C, while linear low-density polyethylene [LLDPE] usually seals around 110? C," Wooster said.
"These new resins can help manufacturers create packages which are easier to run on packaging equipment, which means faster speeds and fewer leakers," Wooster said. "These resins also have better optics. They have high gloss and shine, good seal integrity, are better for modified atmosphere packaging [MAP] to extend shelf life and have a low contribution to taste and odor," Wooster added.
As more processors are adding value to the already convenient salad package by incorporating croutons, cheese and even utensils, the packaging film needs to have good toughness qualities and resistance to pinholing, punctures, abrasions and rough handling. While Affinity PF 1146 delivers improved sealing qualities, PL 1888 features good optical qualities and better abuse properties.
Following Quaker Oat's lead packaging cereal in flexible bags with zippers, some cereal manufacturers are standing up to the challenge. According to industry reports, Kellogg's will debut a breakfast cereal called Country Inn Specialties in flexible, paper laminate bags during the first quarter of this year. To achieve an old-fashioned look, the bags will feature twist-tie closures. Sources indicate Kellogg's does not plan to place its name on the cereal package or market it as a Kellogg's product.
For cereal manufacturers, the advantages of switching from a bag-in-box application to a stand-up pouch are clear, according to Boyd. "Stand-up pouches have reduced material costs using printed roll stock versus unprinted web and printed carton. The inventory costs are reduced due to single process packaging. Labor costs are reduced along with capital investment costs due to the elimination of side seamer and cartoner. Post consumer waste is also reduced."
Besides the capital investment involved in a switch to flexible, cereal manufacturers are concerned that new products introduced in pouches will cannibalize existing products. But cereal manufacturers are slowly discovering the benefits of stand-up pouches, such as increased billboarding opportunities with large facings and eye-catching graphics along with cost savings making flexible packaging an attractive investment, Boyd said.
The Capri Sun pouch from Kraft General Foods is the most notable drink product in a stand-up pouch. "Capri Sun is a very successful product, selling 1.5 billion units annually," Boyd said. But Capri Sun is now facing competition. Minute Maid's contoured pouch is designed for easier entry with a top gusset where consumers punch the straw into the package.
At this stage of the game, the switch to flexible packaging has been mostly in dry products, notes Martin of Kl?ckner. Liquid packaging is still going to be the biggest challenge. "Speeds are a significant issue in beverage packaging," Martin said.
To create a thinner film with improved properties, Eastman has developed an extrusion coating grade LLDPE. Compared to conventional laminations this coating can provide higher seal strengths and comparable performance with a thinner layer of plastic as well as reduce raw material without sacrificing performance.
Clarity is another important quality for flexible packages. "Consumers like to see through the bag. With typical linear low resins, clarity is not as high as low density. So with this new resin, you get the strength of a linear low and the clarity of a low density polyethylene," said Diane Farnham, development specialist, Eastman Chemical.
Extrusion coating can also replace manufacturing steps. "Extrusion coating can replace adhesive lamination of films, in some cases," Foster added. By replacing a purchased film with a direct extrusion coating, packagers can often get adequate performance at a lower cost.
Advanced resin and film technologies create more complex films with better properties. "These films have seven or eight different layers. It is important to design films with the right mechanical properties for the application," said Rimes of DuPont. "Film stiffness and slip qualities are an issue with the newer materials. Sometimes these materials do not handle well on packaging equipment. The new metallocene resins, in particular, need to be modified for the right slip characteristics."
More often than not, packaging engineers want to know about increased equipment speeds. Filler speeds also have to be considered when discussing line speeds. Some equipment can make pouches at 200 per minute, Martin questions whether the filler can handle these speeds. "You have to consider product handling, filling product accurately, minimizing breakage," he said. "This is the part of the equation people forget."
With all the film choices on the market and more in development, making a packaging machine to match changing needs can be difficult. "Everyone is using a different film structure. Converters are able to customize film structures for each customer's needs," Martin said. "When we design a machine we try to keep this in mind and design the machine so that many different film structures can run on a single piece of equipment."
Flexible packaging for value-added foods is here to stay. Processors, converters and equipment manufacturers alike will have to work together to hit the perfect strike.
Bolthouse's new package will be offered at a higher price than a more traditional zippered bag. "The cost of the package will be passed on to the consumer. Initially we were somewhat hesitant about offering a package that would require a higher price, but our packaging people convinced us consumers are willing to pay for the additional value and convenience," McCorkle said.
The Slide-Rite features a unique tamper-evident seal located below the zipper. When opening the package, the consumer slides the zipper and encounters a flexible membrane. The membrane is scored down the center, parallel to the zipper track. Pulling the two sides of the package apart breaks the tamper evident seal. This system reduces the amount of flexible material needed and eliminates the need for consumers to use scissors, said Mark Dutt, business manager for Slide-Rite.
The Slide-Rite bags come as small as 4 in. by 4 in. and as large as 4 ft. by 4 ft. The track of the zipper is made of a polyethylene-based material, while the sliders can be made out of a variety of materials based on the application. Currently the Slide-Rite is available only on pre-made bags. In the next 12 to 24 months, Tenneco hopes to have form/fill/seal applications on the shelf.
Kraft Foods Inc.'s Maxwell House division is packaging its Cappuccino Coolers, an instant sweetened, powdered iced cappuccino mix, in the Slim Stick. Mead Johnson's Enfamil Easy One baby formula is packaged in individual 4 oz. packets for formula in the package.
The package for free-flowing dry products, such as powdered drink mixes, is made on the Sanko FC-1000. "The machine can have up to 10 lanes, depending on the amount of product and size of stick you need," McDermott said.
It can run at speeds ranging from 120 to 1,000 pouches per minute. "For a free-flowing product, like granular sugar, the product can run at 85 cycles per minute on a 10-lane machine, packaging 850 packages per minute."
The package can accommodate a range of product sizes from a fraction of one gram up to 35 grams of product. The machine can also be adjusted for a range of package sizes from 50mm to 180mm long and 12mm to 60mm wide.
The Slim Stick can incorporate an easy-open feature called Fancy Cut. Hosokawa Yoko Co. , Ltd. (Tokyo, Japan) has entered into an agreement with T.H.E.M. for the exclusive use of Fancy Cut easy-open film technology on the Slim Stick. This technology does not require a notch or serrate which could compromise the package structure. This system uses a film which tears in the transverse direction only. This allows the consumer to tear the package across the top and prevents the package from tearing down the side.
T.H.E.M. has teamed up with the Power Group (St. Charles, IL) to offer food processors a chance to outsource this process. Power has seven machines available to quickly bring new products to market, according to Carl Melville, president, The Power Group.