You may have noticed or heard about a new product called a self-heating container, made by a company called OnTech and sold under Wolfgang Puck and other brands. This case study highlights only one of more than 400 technical problems that were solved with TRIZ to make the container a market success.

As shown in the image below, by triggering an exothermic reaction inside, an OnTech beverage container safely heats its liquid content to a desirable temperature so consumers can enjoy coffee while camping, or hot chocolate at a child’s soccer game on a cold day. Of course the challenge for OnTech was to make all of its containers commercially feasible, while providing the required functionality at a reasonable cost.

The Challenge

Here’s how the OnTech container works: A button is pressed on the bottom of the can, which breaks a barrier between calcium oxide and water, which combine to create an exothermic reaction, which releases energy into the internal container, which heats the beverage that sits in an external compartment separate from the chemistry. Nothing about making an exothermic reaction is all that complicated — but making one that heats sterile beverages consistently is complicated enough to present many engineering and cost challenges.

The Process

Work on the container project began where many TRIZ projects do: utilizing substance-field modeling, mathematical modeling, and Taguchi design of experiments to set up the basic structure of the design, and to optimize several of its design parameters. One such parameter for the OnTech project was to make the outside layer of the container strong enough to resist expansion caused by the energy created during the exothermic reaction.

But after this work, several barriers to commercial viability remained, one of which was a physical contradiction related to thermal energy exposure during “retort.” This is the process of heating the beverage for a set amount of time at a certain temperature to kill all pathogens and spoilagens.
 

The problem for OnTech was that certain materials are more able to withstand the retort process than others. As the temperature inside a container rises, as it does during retort, pressure is exerted on the walls of that container, and too much pressure will cause those walls to become misshapen or deformed. At the same time, the cooling cycle creates an internal vacuum that can distort the walls as well.

Metal, for instance, withstands retort very well. But metal is also very conductive, which means if you’re holding it in your hand, and the beverage inside is 140 degrees, you’ll probably feel it. Therefore, metal wouldn’t work for the OnTech application, and the best known alternative was a form of polymer, or plastic, called polypropylene. The very top and bottom of OnTech’s drinking can could be made of metal, but the sides where you hold the can had to be less conductive.

But the problem didn’t end there, as it became further confounded by the fact that there are two internal chambers that are subjected to the retort process, as well as one external chamber, the outside of the can (see Figure 14-1). Moreover, the seams that separate each of these chambers from their adjoining elements are of different natures, utilizing different materials and processes.

If too much heat resides in any chamber for too long, there is deformity and compromised integrity of function. The reason is because heat creates steam, which increases pressure. When pressure increases, it can cause various deformities in the walls of a chamber as it is built up and released. In turn, these deformities can then interfere with proper system functioning. Therefore, you need steam to do its job in the thermal warming cycle, but its job is bi-polar: It has to collapse at some time in the retort process, but it can’t collapse and create unwanted deformities.

The Results

As simplistic as we’ve made the OnTech case seem, its innovation accomplishment was no small task, and TRIZ provided an engine for acceleration on a number of fronts. In fact, years before it was doing its research and development, American National Can (ANC) had completed work on its Omni-Bowl project, which addressed certain of the same issues that OnTech addressed with its product — but not the innovative self-heating aspects.

ANC is a large flexible-packaging company with about 2,000 different products, and tens of millions of investment later, its Omni-Bowl project yielded some important breakthroughs. One such breakthrough was figuring out how to bind metal and plastic into a container seam that would survive retort. None, however, were as technically demanding or as innovative as the ones the OnTech team came up with in their labs at a cost of a small fraction of the ANC solution.

The biggest reason for this was because TRIZ gave the OnTech inventors a small handful of paths to travel, rather than an infinite number of possible paths. We’ve already discussed what happens when you trade rationally targeted convergence for limitless divergence. Basically you end up in the weeds.

Although it might seem good at first to diverge all over the place, its better to Define the course, Model the variables, Abstract the problem, Solve it with analogical thought, and Implement your solution (Tactical TRIZ methodology). With this roadmap, a TRIZ problem-solver or team can make the course of convergent divergence a valuable reality. 

This case study is featured in more detail in the book Insourcing Innovation from Breakthrough Performance Press, the publishing division of BMG.