Pouch-perfecting improvements

Unilever’s vast array of food brands include Knorr its number one-selling brand and Lipton two of the most trusted names found on supermarket shelves. The packaging for these top selling foods is integral to consumer satisfaction and for more than three decades Knorr and Lipton food products have been presented in sealed pouches made of paper/polyethylene/aluminum foil/PE (PPFP).

However recent developments in packaging film technology prompted Unilever Foods North American Savory Division Englewood Cliffs NJ to rethink that traditional construction. It did and is replacing the foil layer with a technologically advanced thin barrier metallized biaxially-oriented polypropylene (BOPP) film. The “drop-in film replacement” manufactured by Toray Plastics (America) permitted Unilever’s Savory Division to achieve greater barrier protection and produce a better consumer product. The change has also allowed Unilever to improve brand equity create an aesthetically superior package and gain significant production savings.

“Toray Plastics said it had a product that would meet or exceed all of our technical specifications” says Michael Hughes group manager packaging technology Unilever Foods NA of Englewood Cliffs NJ. But the proof was in the package. “In a six-month trial the pouches made with Toray’s metallized barrier OPP Torayfan® PC1 outperformed a control group of regular PPFP packaging in delivering a better food product because of their superior moisture and oxygen barrier protection properties. It became apparent that by making a switch we would be able to not only achieve improved brand equity but significant economic advantages as well.” Torayfan PC1 a 50-ga metallized BOPP which replaced foil of .000275” or .000285” is part of Unilever pouch structures that range in thickness from 3.1 mil to 4.3 mil depending on the application.

Unilever first adopted Torayfan PC1 film for Lipton-branded side dishes in January 2005 and soups in July before continuing with Knorr products in October. “This was not a decision made in haste especially with Knorr which was first introduced in 1838 and today is our biggest selling brand” states Hughes. Knorr is sold in more than 80 countries with sales totaling more than European €3 billion (approximately US $3.5 billion). “Both the Knorr and Lipton brands have an image of quality that is known and trusted by consumers and maintaining that image is one of our top priorities.”

Third in line for conversion is Unilever’s Lawry brand seasonings which are moving now into the new structure; the conversion is expected to be completed by the end of March 2006.

Punctures prevented customers confident

By changing from foil to metallized BOPP Unilever was able to achieve several performance improvements. “Better puncture resistance was very important to us because many of the Knorr and Lipton products contain freeze-dried noodles which have very sharp edges” says Hughes. The danger of punctures is especially severe when the pouches are compressed as they are packed inside shipping cartons. “The Torayfan film has outstanding puncture resistance so we didn’t need to use special metallocene films in the lamination. According to the feedback from retailers that unpack the cartons the problem of punctured pouches has been practically eliminated.”

The new packages also offer increased shelf life. “Some of the punctures that used to occur with foil were almost microscopic and thus invisible to the naked eye” Hughes explains. “They were so tiny that even though the fine powders inside the pouch were unable to get out air and moisture were able to get in shortening the shelf life of the product. Testing has shown that this problem does not occur with the new Torayfan film.”

Improved graphics and consumer appeal was another benefit. “The problem with foil is that creases or wrinkles that occur during handling are permanent” says Hughes. “The pouches are handled by automated equipment when they are packed into cartons then by stock clerks when they are taken out and put on the shelf. Consumers may also pick them up to examine them and read the ingredients. With all this handling they can quickly appear to look shopworn. With plastic film however creases and wrinkles are temporary and the pouch quickly regains its fresh appearance. So the graphics appear sharper and clearer on the new film structures than they ever were on the PPFP pouches.”

Production benefits realized

In addition to improvements that were apparent to the trade and to consumers Unilever was also able to achieve a number of internal production benefits. “One of our biggest concerns was whether the new pouches would be able to run at the same speed as the old ones on our high-speed form-fill-seal filling equipment” Hughes notes. “Some of our machines operate in intermittent rather than smoother continuous motion and the pouches are subjected to quite a bit of stress. We were concerned that the new packages might not be able to withstand this type of handling. To our surprise however we found that with just a few simple modifications we were able to operate all of the machines at their maximum speeds.”

Another benefit was improved sealing performance. “Because Torayfan PC1’s corona-treated surface accepts sealants so readily we were actually able to reduce the amount of sealant required to achieve the same bond strength” Hughes explains. “With hundreds of millions of pouches being sealed this translates to a significant economic benefit.” Unilever reports that packaging materials costs are either reduced or at parity with the previous structures.

One unexpected benefit was the ability to standardize pouch sizes. “Our freeze- dried soups sauces and side dish mixes vary so with foil we had to optimize the size of each pouch to avoid underfilling or overfilling either of which increases the chance of puncture” says Hughes. “Torayfan PC1’s outstanding puncture resistance allowed us to standardize using about 50 percent fewer sizes. This reduced the need for frequent changes allowing us to increase production rates even more.”

With positive results with all the conversions in North America Unilever is considering standardization on a global basis. “Our affiliates in Europe and Australia have expressed strong interest in the new package” says Hughes. “There is little doubt in my mind that we will soon be using it worldwide. Toray has been a true marketing partner to us in every sense of the word.” —Rick Lingle

See sidebar to this article: Film details

See sidebar to this article: Converter details