Microwaveable Steel Can

The package consists of steel can walls, an EZ Open end, plastic end, plastic overcap and insulating foam label.

06/09/06 One of the oldest food packages is now microwavable: a steel can. The Fusion-Tek Microwavable Can from Ball Corp. is the first microwavable steel can.

Commercial quality production of the package is scheduled to begin in October. Initial interest is primarily for ready-to-eat meals such as soups and stews, says Michael Vaughn, Ball's vp, packaging innovation.

A regular steel food can does not heat in the microwave because microwave energy cannot pass through steel, but Fusion-Tek’s plastic end allows microwave energy to pass through the product inside the can, heating it quickly and evenly in 2-3 minutes.

The 307x306 Fusion-Tek can holds approximately 15 oz of product. The package consists of steel can walls, an EZ Open end, plastic end, plastic overcap and insulating foam label.

Shelf-stable, tamper- and puncture-resistant, the Fusion-Tek can provides the same shelf life as the traditional steel can because its plastic end has an oxygen barrier that ensures freshness for at least 18 months.

The secret is the plastic end

Using Ball’s proprietary process, a plastic end is joined directly to the steel can wall. Vaughn informs us that the end is made of multilayer polypropylene/ethylene vinyl alcohol (EVOH) barrier plastic. The end is not injection molded nor is seamed on, but is "converted by Ball into a useable form," Vaugh explains. "And we’ve developed a proprietary process for joining the plastic to the metal."

Engineers from Ball Packaging and subsidiary Ball Aerospace worked together to develop the proprietary technology needed to join the plastic end to the steel can walls. Both groups were looking for a way to get microwave energy into metal: Ball Packaging engineers for food cans and the Aerospace engineers for microwave guidance systems.

The mixed-material package remains viable in the steel recycling stream. According to the Steel Recycling Institute, the plastic end simply burns off.

Seamless process with seaming

The cans will be shipped to packagers with the plastic end on. The packager will fill the cans, seam the EZ Open end on, and apply labels and overcaps.

The cans requires overpressure sterilization, but can be processed faster than plastic microwavable containers because metal transfers heat into the product faster and also cools faster.

But isn't steel a microwave no no that can cause arcing?

Due to physics and the geometry, the answer is no, responds Vaughn. For one thing, the round profile means there are no corners.

"Only very thin sections of metal, such as unfolded aluminum foil, cause arcing in the microwave," he says. "The metal can is far too thick for this to be an issue." The can wall is 0.0072" thick.

What about costs?

It is competitive with other microwavable packaging, Vaughn says. "It offers the potential for processing cost savings due to its supply chain efficiency. Because consumers have proven that they are willing to pay for convenience, Fusion-Tek gives our customers the ability to capture a higher retail price for their products and potentially realize savings over using other microwavable packaging."

Ball would consider other sizes depending on demand.