Corrugated Cardboard

Stamp on a corrugated cardboard box.

Official stamp on a corrugated cardboard box.

I was recently on a search, looking by the bins near our neighbor’s apartment complex, peeking behind the store around the block, looking for the right one. And then I found her — a flat yet sturdy beauty, about 6 feet tall, pleasantly thick in all the right places, clean around the edges, and in excellent overall shape. She was the mother of them all, a huge cardboard box, and what a great playhouse it would make for my 2-year old. As I threw the heavy carton into the back of my truck, I imagined what it must have carried, being so strong, and what it would become after I got through with it.

A LITTLE WAVE OF HISTORY

Long before cardboard played house, it played a role in the Industrial Revolution, when the increase in manufactured products signaled a change in the nature of the consumer market. As demand for goods increased, so did the need for a lighter means to transport them. Still, we owe the creation of cardboard and its many uses to a series of small design changes.

It all started when a new process enabled flimsy sheets of paper to be crimped into repeated undulating pattern, creating more rigid, stronger material for packaging fragile goods. Later, in 1856, Edward C. Haley filed a patent on “undulated paper,” finding it useful as a liner for tall hats. Another patent for corrugated cardboard was introduced in 1871, when Albert Jones of New York added a single liner sheet to one side of the undulated paper. This addition would make it more suitable as a wrapping material for Jones’ bottles and glass lanterns. Three years later, G. Smyth invented the first machine for producing large quantities of corrugated cardboard, and yet another gentleman named Oliver Long added liner sheets to both sides. This material is corrugated cardboard as we know it today.

Cardboard container advertising, 1942.

Ad for cardboard containers from 1942.

A Brooklyn printer and paper-bag maker named Robert Gair can be thanked for boxing it up. In 1890, he invented a carton made of pre-cut flat pieces. Gair’s creation (as with many other innovations) was the result of a happy accident; while he was printing an order of bags, a metal ruler used for creasing shifted in position and cut through the paper. Gair discovered that by simply cutting and creasing cardboard as well, he could make boxes in large quantities.

Inside view of a corrugated cardboard box.

Folded corrugated cardboard box.

SEVERAL STRONG POINTS

A little structural engineering goes a long way, it seems. The secret to the strength of cardboard is all in that wave of fluting sandwiched between the flat liner boards and glued together, usually with cornstarch and some chemicals. When used in packaging, stacking boxes so that the flutes line up in the vertical direction greatly increases its strength potential. (It’s even possible to stand on a vertically stacked box, though that same box on its side will collapse.) Still, 70% of its strength is found in the corners of each box, making squarely stacked cartons incredibly strong.

Cardboard that is used for shipping is tested and rated using two standardized measures. One is the Edge Crush Test (ECT), which determines how well a box will hold up during stacking and is measured in pounds per square inch (psi). The Burst Strength Test (BST) or Mullen Test indicates how much weight a box can hold without failing. Both ratings can be found stamped on one of the bottom flaps of corrugated cardboard boxes in the Box Manufacturer’s Certificate. Higher numbers indicate sturdier boxes.

Cardboard eggholder patent, 1877.

Patent for a cardboard eggholder, 1877.

THE DARK, TOXIC TRUTH

As so often with large production processes that make our lives a bit easier, the manufacturing of cardboard has a dark side. The most obvious danger lies in the unchecked harvesting of pine for paper pulp. The second is even more troubling.

In the nineteenth century, a chemical pulping process was developed that allowed wood (in this case, pine) to be turned into a soluble pulp for strong, relatively long-lasting paper. This chemical pulping is still used, removing all the parts of the wood which are not cellulose. Lignin, a carbohydrate that cements adjacent wood cells together, is taken out in this process.

Originally, wood pulp was cooked in lye alone, but this produced a rather weak paper. The addition of sodium sulfide to the pulp produced a much stronger paper. This process is called the kraft process (from the German word for strong.) About 80% of this kraft pulp is wood and the remaining 20% consists of lye and sodium sulfide. The pulp is cooked, or digested, at 338 degrees Fahrenheit for three hours until most of the lignin is made soluble. The liquid is then drained off and the pulp is washed to remove the chemicals.

cardboard box print, detail.

Detail of a cardboard box print.

The result: a pulp that is dark brown in color. Corrugated cardboard and grocery bags are both made from this kind of paper. (If white paper is desired, the pulp must be bleached.)

The problem with the kraft process is what remains; this black liquid contains lye, soda ash, sodium sulfide, and lignin. In the past, this would have been discharged directly into a lake or river, causing significant water pollution. Today, economical production of kraft paper relies on the recycling of these components in a furnace.

The problem of air quality around kraft paper mills is a continuing one and efforts to reduce emissions are costly to the mills, but many are making it a priority to make the process more efficient. More and more manufacturers use recycled cardboard. For those that do not, there has been a growing number of paper mills that have at least been using FSC (Forest Stewardship Council) certified sources. With the demand for more conscious production, these manufacturers will hopefully meet new strict standards.

Cardboard art: Claude Closky's "All the ways to close a cardboard box" (1989) (Image courtesy closky.info)

Claude Closky’s “All the ways to close a cardboard box”, 1989. (Image courtesy closky.info)

HIGH DESIGN

Besides being used to ship product, the versatility of cardboard makes it a perfect candidate for use in design. In the past 40 years, a number of high profile designers and architects began experimenting with cardboard as an alternative to  traditional building materials, using it in shelters and furniture. In 1972, L.A. architect Frank Gehry designed his famous “wiggle chair” completely out of cardboard, and his design continues to sell over thirty years later. In 1995, Japanese architect Shigeru Ban used columns of cardboard tubes in the Takatori Kyokai Church in Kobe, Japan; he later used them in his UN design for refugee shelters in Rwanda in 1999 and in the stunningly beautiful Japan Pavilion in Hannover, Germany for Expo 2000. Most of all, these designs focused on the innovation of non-traditional materials, creating a new set of possibilities.

Vintage ad for cardboard container from 1942.

Ad for cardboard containers, 1942.

HANDLE WITH CARE

It goes to show that simple materials such as cardboard can be strong, playful, serious, versatile, and even aesthetically pleasing all at once. Who of us hasn’t used a box as a playhouse during childhood? Moved her entire life’s possessions to a new home in a bunch of boxes found at the local grocery store? Or, sadly, come across the body of someone sleeping on the sidewalk, their feet sticking out of a carton? Cardboard continues to remind us of its steadfast presence in our daily lives, a material that lends itself out readily when we need it the most. Though new innovations will undoubtedly signal the arrival and departure of less-than-natural manufacturing materials, cardboard may continue to serve as a valuable tool for years to come. Ultimately, however, we must respect materials like this one if we’re to continue benefiting from them.

Cardboard container advertising, 1942.

WWII ad for cardboard containers, 1942.

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