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ConAgra pops up a winnerWhen brand managers and packaging engineers at ConAgra saw an opportunity to delight the consumer and differentiate their microwave popcorn brand, they didn’t hesitate.

Pat Reynolds | VP/Editor

What do you get when you combine a special

dry-bond adhesive, in-line laser scoring, clever

problem-solving in the transport of large rolls of

laminated material, and custom modification of a horizontal

form/fill/seal machine so that it produces a unique venting

feature in the finished package? At Omaha-based ConAgra

Foods, you get an Orville Redenbacher’s Pop Up Bowl that

is a significant improvement over the traditional paper

microwave popcorn package. No wonder the pack-

age won the Highest Achievement Award in the

2012 FPA Awards competition.

The goal behind this packaging development

was to come up with a package that would turn

into a wide-mouth bowl as popping occurred. This

eliminates the need to pour popcorn into a separate bowl. It also

provides new usage occasions because consumers can now take the

package on the go without worrying about what to do with

their bowl when the popcorn is gone.

The Redenbacher brand has been a leader in the

microwave popcorn category for years. For most of that

time, ConAgra’s in-house converting operation in its Maple

Grove, MN, facility has been the source of the microwave

popcorn bag material. But to produce this new material—a

unique combination of paper, polyester, sus-

ceptor patch, tear tape, and new adhesives

all combined in an extraordinarily creative

design—in the same plant on existing

laminating equipment took some doing.

First, all adhesives had to be water-

based because the plant didn’t have—and had no

interest in applying for—the regulatory approval to handle the volatile

organic compounds inherent in solvent-based adhesives. A dry-bond

LASER SCORING. The package’s tear-away film lid requires in-line laser scoring to reduce its tensile strength in precisely the desired locations. Folding cartons with high-impact graphics remain a fixture in the store aisle.

March 2012 | PACKAGING WORLD

ConAgra

adhesive system from Henkel (www.henkelna.

com) was crucial in overcoming the unique lamina-

tion challenges involved in getting the microwave

susceptor patch into the complex lamination.

Second, the bag’s opening feature—a tear-away

polyester film lid—is what allows the package to

transform into a stable wide-mouth bowl after open-

ing. To provide consistent removal of the film lid by the consumer,

ConAgra used in-line laser scoring of the 90-ga polyester film. This

reduces its tensile strength in precisely the desired locations and

facilitates opening. In addition, a polyester-based pressure-sensitive

tear tape was laid over the top of the laser score to provide consistent

tracking of the tear, prevent zippering of the tear, and eliminate loose

film edges after opening.

Third, consistent and safe venting of steam during microwave cook-

ing was critical to the functionality of the package and to consumer

safety. A unique and patent-pending system was created that involves

punching a vent feature in the laminated structure during the package-

forming process on the PSA (www.psautomation.com) horizontal

form/fill/seal system. Adhesive around the venting feature is then

sealed to prevent leaking of oil during transport until the package is

used in the microwave oven. During cooking, pressure builds up and

the adhesive seal releases to vent steam safely.

Two-up produCTionAccording to ConAgra’s David France, senior principal packaging

engineer in Packaging Research, Quality, and Innovation, the convert-

ing process is a two-up process. “We make the rollstock for two pack-

ages of material side by side and then slit it at the end for rewind,”

says France.

The laminating process begins with 90-ga polyester going through a

two-side corona treatment that allows good bonds to develop between

the polyester and the inks and adhesives that need to be applied. Next

is in-line laser scoring of the polyester on a Preco (www.precoinc.

com) system to achieve the easy-opening feature described above. A

flexo print station follows, where the dry-bond adhesive is applied in

register for subsequent placement of the four susceptor patches—two

for each package. Infrared drying dries the adhesive until it’s just tacky

enough for the susceptor patches to bond firmly. Vacumet (www.

vacumet.com) provides the metallized susceptor patch material in

the form of continuous strips, and the ConAgra system cuts individual

patches from these strips.

Now the four polyester-based, pressure-sensitive tear tapes men-

tioned above are applied. These come from Payne (www.payne-

worldwide.com). “They help give the consumer a nice, even removal

of that polyester lid,” says France. “The polyester has a tendency to

want to zipper, and its central tear resistance is not really great, so it

doesn’t quite follow the laser score lines as evenly as we’d like if we

don’t apply these tear tapes.”

In the next station the sidewall paper, supplied by Thilmany (www.

thilmany.com), is laminated into the structure from four individual

unwinds; again, a water-based adhesive from Henkel is used.

A central impression printing system with five stations—four flexo

stations for inks and one gravure for the adhesive that will later make

it possible to form the package on the package-making/filling system—

comes next. Infrared and hot air drying follows. Finally, a gravure station

prints adhesive that later permits the final seal operation on the filled

bag. All that remains is final drying, a chill roller, and rewind of the fin-

ished lamination.

The TrAnsporT ChAllengeAfter slitting, a single roll is about 193⁄4 inches wide and 24 inches

in diameter, and it weighs about 140 lb. “Transporting these rolls was

challenging,” notes France, “because they have sort of baggy soft edges

and hard gauge-banded areas in the center. [“Gauge band” is an abrupt

increase in film thickness in a small area in the transverse direction; it’s

visible as a hump around the circumference of the slit roll.] We discov-

ered they don’t stack as well as the normal solid roll of paper. So we

came up with reusable plastic totes, four rolls per tote.” Keeping track of

and maintaining the totes is simplified by the fact that they never leave

ConAgra’s possession as they move from a ConAgra converting plant

to a ConAgra packaging plant.

The PSA horizontal form/fill/seal machine into which the rolls are

fed for pouch forming and filling had to be modified almost as exten-

sively as ConAgra’s converting operation. “Almost every operation in

the tube forming, sealing, and filling process had to be modified to deal

with this package because the material is flimsier in some areas than

a traditional paper popcorn bag,” says France. “The polyester sections

have memory, whereas the paper bag will take a crease and hold the

COMPLEX STRUCTURE. Polyester, two paper sidewall strips, two strips of polyester-based tear tape, the susceptor material, three different adhesives, and four different inks go into the complex, award-winning structure.

“When we heard time and again in focus groups that this pop up bowl concept, if we

could pull it off, would take over the market for microwave popcorn, we pursued it.”

PACKAGING WORLD | March 2012

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crease. That created challenges in the handling process where we bring

the material together for the lap seal.

Also, because of the unique adhesives, we had to take special care

in the stations of the machine where we open the bag and present it to

the filling apparatus.”

But with help from PSA, the modifications were made with no sac-

rifice in production speeds, a number France prefers not to identify. An

intermittent-motion machine, the PSA equipment forms rollstock into a

gusetted tube and then makes a cross seal. A rotary knife cuts the lead

package from the continuous tube and reorients it 90 degrees so that

one end can be opened up for volumetric depositing of corn, as well as

other ingredients such as oil.

MArCh 2011 debuTFrance says the new package hit store shelves in March of 2011 and

has replaced the old package format for some SKUs. “We are reevalu-

ating whether to make it standard for the entire Orville Redenbacher

line,” he adds.

While the old bag was basically two pieces of paper, a microwave

susceptor patch, a couple of adhesives, and three inks, the new bag is

considerably more complex: polyester, two paper sidewall strips, two

strips of polyester-based tear tape, the susceptor material, three dif-

ferent adhesives, and four different inks. France admits that it currently

comes with a slight upcharge compared to the bag it is replacing, but

he points out that the paper bag has been cost-reduced over the past

25 years or so. He expects some of that cost reduction to happen with

this still very new structure, which was designed in-house by France and

ConAgra colleague Charlie Gorman.

Consumers, notes France, pay no upcharge for the new package.

So how does management justify the added cost of the new package?

“We knew that the popcorn package market had been stuck in this

traditional package for a long time,” says France. “And every time we

talked to a large number of consumers, we knew that the utility of the

old package wasn’t what it should be. So when we heard time and again

in focus groups that this pop up bowl concept, if we could pull it off,

would take over the market for microwave popcorn, we pursued it. It’s

part of our belief in always trying to find ways to add improved benefits

for the consumer and to differentiate the brand.”

As for the package’s technical merits, they’re best summed up in

ConAgra’s FPA Awards submission form:

“This is by far the most complex lamination ever produced for high-

volume microwave popcorn packages. The use of in-line laser scoring of

monolayer polyester, combined with tear tape, is unique to this popcorn

package and new to our production facility. Also new to our facility is

the use of dry-bond adhesive for bonding of the susceptor patch to the

structure. The form/fill/seal adhesive was custom developed for this

application, as was the adhesive system for the tear tape. The opening

and venting features are part of the patent-pending design that provides

the consumer with a clean, convenient, wide-mouth bowl after opening.”

A high achievement indeed. pw

(#72871) Copyright 2012 Summit Media Group. Reprinted with permission from the March 2012 issue of Packaging World. For more information about reprints from Packaging World, contact PARS International Corp. at (212) 221-9595.

This PDF is authorized for electronic distribution & limited print distribution through June 27, 2013.Please see your order confirmation for details of allowable usage.