Corrugated fiberboard
Cardboard is a lay term used to describe a variety of heavy wood-based types of paper, notable for their stiffness and durability. Paperboard used for food and small consumer goods, as well as corrugated board used for larger goods and shipping cartons are the most common examples of items referred to as Cardboard.
Paperboard (cardboard) was first invented in China some time in the 15th century, and is used for a wide variety of purposes. One of its more common uses is as a packaging material.
History
The first commercial paperboard box was produced in England in 1817 [1].
Corrugation
In the mid 19th century, an ingenious concept enabled flimsy sheets of paper to be transformed into a rigid, stackable and cushioning form of packaging for delicate goods in transit.
Corrugated (also called pleated) paper was patented in England in 1856, and used as a liner for tall hats, but corrugated boxboard would not be patented and used as a shipping material until December 20, 1871.
The patent was issued to Albert Jones of New York, New York for single-sided (single-face) corrugated board. Jones used the corrugated board for wrapping bottles and glass lantern chimneys. The first machine for producing large quantities of corrugated board was built in 1874 by G. Smyth, and in the same year Oliver Long improved upon Jones' design by inventing corrugated board with liner sheets on both sides. This was now corrugated board as we know it today.
Prefabricated Containers
The American Robert Gair invented the corrugated box in 1890, consisting of pre-cut flat pieces manufactured in bulk that folded into boxes. Gair's invention, as with so many other great innovations, came about as a result of an accident: he was a Brooklyn printer and paper-bag maker during the 1870s, and while he was printing an order of seed bags a metal ruler normally used to crease bags shifted in position and cut the bag. Gair discovered that by cutting and creasing board in one operation he could make prefabricated cartons. Extending this to corrugated boxboard was a straightforward development when the material became available. By the start of the 20th century, corrugated boxes began replacing the custom-made wooden crates and boxes previously used for trade.
The corrugated carton was initially used for packaging glass and pottery containers, which are easily broken in transit. Later, the case enabled fruit and produce to be brought from the farm to the retailer without bruising, improving the return to the producers and opening up hitherto unaffordable export markets. (There had previously been a great deal of waste when, for example, oranges were craned out of the hold of a ship, having been bulk loaded into it.)
Will Keith Kellogg first used paperboard cartons to hold flaked corn cereal, and later when he began marketing it to the general public, a heat-sealed waxed bag of Waxtite was wrapped around the outside of the box and printed with their brand name. This marked the origin of the cereal box, though in modern times the sealed bag is plastic and is kept inside the box rather than outside.
Today paperboard packaging in general, and especially products from certified sustainable sources, are receiving new attention, as manufacturers dealing with environmental, health, and regulatory issues look to renewable resources to meet increasing demand environmentalism. It is now mandatory in many countries for paper-based packaging to be manufactured wholly or partially composed of recycled as well as tree-free fibers.
Today's corrugated board
Today's corrugated board usually consists of outer flat sheets (liners) of puncture resistant paper, sandwiching a central "filling" of corrugated short fibre paper (fluted paper, or "medium"), which resists crushing under compression and gives cushioning protection to the box's contents.
The "liner" and "medium" (outer and inner portion of the final corrugated board product) are glued together along the outsides of the peaks and valleys of each flute, normally using starch adhesives. The starch is derived from corn, wheat or potato. Thus the complete make-up of corrugated board is from natural, sustainable materials in plentiful supply and the board is fully recyclable and can be pulped down to make more paper for more board once it has ended its own life.
The board has high end-to-end strength along the corrugated flutes, so the box is normally designed with the flutes running vertically for stacking strength. The modern method of testing the stackability of a corrugated box is called the Edge Crush Test (ECT), but until recently boxes were measured with a bursting strength test known as a Mullen Test. Box Manufacturers often certify the strength of boxes by imprinting a Box Maker's Certificate (BMC) on the bottom of cartons. This will contain the name of the company that made the box as well as the city and state where it was manufactured along with the pertinent test information.
Paper made from hardwood, short fibre pulp, has good compression strength and is easily moldable with moisture and heat, but is weak in tension and tears easily. Paper made from softwoods, with their longer fibres, on the other hand, is strong in tension and resists puncturing and tearing better and is less plastic, so tends to keep its shape. It also provides a better surface for printing.
Common flute sizes are "A", "B", "C", "E" and "F" or microflute. Flute size refers to the measurable thickness of the board (outside liner-medium-inside liner) which is made variable by paper thickness and size of flutes, the order from thickest to thinnest being "A", "C", "B", "E", "F".
Double and triple-wall corrugated is also manufactured for specialized industrial applications and, at the other extreme, microflute is manufactured for fine printed packaging or displays or presentation packaging for high-value contents such as spirits, perfume, jewelry, etc. Almost all corrugated boxes are shipped flat for ease and economy of transport, then erected, filled and closed at packing stations.
Old corrugated cartons are an excellent source of fibre for recycling. They can be compressed and baled for cost effective transport to anywhere in need of fibre for papermaking. Thus they help developing countries without sustainable wood resources build a paper and packaging industry locally and develop their exports to global markets.
Corrugated board is manufactured on high-precision machinery lines called Corrugators running at 500 lineal feet per minute or faster. Various types of "converting" machinery are used to manufacture boxes from the board coming off the corrugator. The most important, universal and revolutionary of all converting corrugated equipment is the "Flexo Folder Gluer" (FFG), which is a machine that in one single pass prints, cuts, folds, and glues flat sheets of board to convert them to boxes for any application, from storing old family pictures to shipping the biggest of plasma TV sets to the global market. The most advanced of FFG's can run at speeds of up to 26,000 boxes per hour.
A box factory may be started up with simple, sometimes old equipment. Additions and/or upgrades can be performed as demand expands and growth is affordable.
See also
- Bluebottle, who wore cardboard pants
- Cardboard boat race