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Cardboard
is a heavy wood-based type of paper, notable for its stiffness
and durability. It 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 cardboard box was produced in England in
1817 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 cardboard 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 cardboard. Jones
used the corrugated cardboard for wrapping bottles and glass
lantern chimneys. The first machine for producing large
quantities of corrugated cardboard was built in 1874 by
G. Smyth, and in the same year Oliver Long improved upon
Jones' design by inventing corrugated cardboard with liner
sheets on both sides. This was now corrugated cardboard
as we know it today.
Prefabricated Containers
The
American Robert Gair invented the corrugated cardboard 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 cardboard in one operation he could
make prefabricated cartons. Extending this to corrugated
cardboard was a straightforward development when the material
became available. By the start of the 20th century, corrugated
cardboard boxes began replacing the custom-made wooden crates
and boxes previously used for trade.
The corrugated case 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 cardboard 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.
Corrugated packaging has undergone a minor resurgence in
recent times due to the trend towards environmentalism.
It is now common for cardboard to be manufactured with a
partial content of recycled fibers.
Today's corrugated cardboard
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 cardboard 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.
Paper made from hardwood, short fibre pulp, has good compression
strength and is easily mouldable 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 microflute. Flute size refers to the measurable
thickness of the board (liner-medium-liner) which is made
variable by paper thickness and size of flutes. Double and
triple-wall corrugated is also made for industrial applications,
and at the other extreme, microflute is made 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 a packing
stations.
Old corrugated cases 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 much afforestation
to build a paper and packaging industry locally and develop
their exports to global markets.
Corrugated board is made on high-precision machinery lines
called corrugators. Various types of "converting"
machinery are used to make and print boxes from the board
from the corrugator. A box factory may be started up with
simple, sometimes antique, equipment and added to/upgraded
as demand expands and growth is affordable.
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