The Science Of Cardboard

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In 2020, the United States hit a record high in its yearly use of one the most ubiquitous manufactured materials on earth, cardboard. As of 2020, just under 97% of all expended corrugated packaging is recovered for recycling, making this inexpensive, durable, material an extraordinary recycling success story.

THE RISE OF PAPER PACKAGING
This processed pulp is then used to produce paper. Paper making machines use a moving woven mesh to create a continuous paper web that aligns the fibers held in the pulp, producing a continuously moving wet mat of fiber. The invention of several paper-based packaging forms and processes stemmed from this boom, with the corrugated fiberboard shipping container quickly becoming the most dominant.

INVENTION OF CORRUGATION
The first known widespread use of corrugated paper was in the 1850s with an English patent being issued in 1856 to Edward Charles Healey and Edward Ellis Allen. Three years later, Oliver Long would patent an improvement on Jones design with the addition of an adhered single paper facing to prevent the unfolding of the corrugation, forming the basis for modern corrugated fiberboard.
American Robert Gair, a Brooklyn printer and paper-bag maker, had discovered that by cutting and creasing cardboard in one operation he could make prefabricated cartons.

In a partnership with the Thompson and Norris company, the concept would be applied to double-faced corrugated stock, giving rise to the production of the first corrugated fiberboard boxes. In 1903, the first use of corrugated fiberboard boxes for rail transport occurred when the Kellog brothers secured an exception to the wooden box requirement by railroads of the Central Freight Association.

HOW ITS MADE
Rolls of paper stock are first mounted onto unwinding stands and are pulled into the machine at the feeding side of the corrugator, also known as the "wet end". The paper medium is heated to around 176-193 degrees C , so it can be formed into a fluted pattern at the corrugating rolls. The corrugating rolls are gear-like cylinders that are designed to shape the paper medium into a fluted structure as it moves through them. As the newly formed fluted paper leaves these rolls, an adhesive is applied to the flute tips and the first liner is roller pressed on.

The paper stock that forms this liner is often pre-treated with steam and heat before this binding process. The adhesives used in modern corrugated fiberboard are typically water-based, food-grade, corn starches combined with additives. A second liner is applied by adding adhesive to the fluted tips on the other side of the paper medium. After curing, the sheets may be coated with molten wax to create a water-resistant barrier if the packaging is expected to be exposed to excessive amounts of moisture, such as with produce or frozen food products.

PAPER SOURCE
While the first packaging papers relied on the chemical based Kraft pulping process, modern production relies primarily on mechanical pulping, due to its lower cost and higher yield. When a production run of corrugated fiberboard is done, a target set of specifications based on customer requirements, determine both the quality control and physical properties of the fiberboard.

BOXES
Corrugated sheets are run through a splitter-scoring machine that scores and trims the corrugated stock into sheets known as box blanks. Within the flexographic machine, the final packaging product is created. Flexographic machines employ both printing dies and rotary die-cutters on a flexible sheet that are fitted to large rollers. Additionally, a machine known as a curtain coater is also utilized to apply a coat of wax for moisture-resistant packaging.

RECYCLING
The slurry is sent through an industrial magnet to remove metal contaminants. Chemicals are also applied to decolorize the mixture of inks within the slurry. Because the paper produced by purely recycled material will have a dull finish and poor wear characteristics, virgin pulp is typically blended into the slurry to improve its quality. This blended pulp is then directly used to produce new paper.

Recycling paper based packaging is so effective that only 75% of the energy used to produce virgin paper packaging is needed to make new cardboard from recycled stock. Aside from diverting waste material from landfills, it requires both 50% less electricity and 90% less water to produce.

KEY FOOTAGE
Georgia-Pacific
Corrugated Boxes: How Its Made Step By Step Process | Georgia-Pacific
https://youtu.be/C5nNUPNvWAw

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