Chemical Engineering August 2022 - 22

Chem Chronicles
'Eye it Before You Buy It': The Invention of Cellophane
Transparent polymer film started with an accident . . . and spurred a packaging revolution
O
ne night in Paris, in 1900,
Swiss chemist Jacques
Brandenberger was enjoying
dinner in a restaurant
when he noticed that a fellow
patron had spilled a glass of wine.
As waiters scrambled to clear the
table, it occurred to Brandenberger
that the process of removing and
replacing the soiled tablecloth was
time-consuming and inefficient. He
began to mull an application of research
he had been conducting into
the organic polymer cellulose. Brandenberger
conjectured that he could
spray liquid viscose, created from
natural sources of regenerated cellulose,
onto fabric and thereby create
waterproof coatings for tablecloths
and other textiles.
Brandenberger's initial experiments
in this vein were promising, but ultimately
disappointing. The fabric coatings
he produced were indeed waterproof,
but the coatings proved far too
stiff to maintain fabric pliability. But
Brandenberger noticed something of
interest: the coatings could be peeled
off the fabrics without difficulty, yielding
a thin, diaphanous film. He began
to conceive that the value in his material
lay not only in its water resistance
but also in its transparency.
Commercial juggernaut
By 1912, having enhanced his material
(especially through the addition of
glycerin, to soften it), Brandenberger
had patented his product and designed
a manufacturing process for
it, selling the commercial rights to the
firm Comptoir des Textiles Artificiels
(CTA). Brandenberger called the film
" Cellophane, " a portmanteau of cellulose
and the French word diaphane,
meaning
transparent.
The
early
adopters of this transparent film were
food product manufacturers, such as
the American candy manufacturer,
Whitman's, which was a major customer
by 1912. Companies like this
recognized cellophane's potential to
revolutionize the packaging and retailing
of perishable consumer goods.
Intrigued by the vast potential of
this product, the DuPont company
22
purchased the exclusive rights to
make and sell cellophane in the U.S.
in 1923. In 1924, DuPont chemist
William Hale Church reformulated
the transparent film, developing a nitrocellulose
lacquer that rendered it
not only waterproof but more moisture-proof,
enhancing its fresh-food
preservation properties.
DuPont's innovations also extended
to production. Initially, making cellophane
required the time-consuming
dissolution of cellulose from materials
like wood, celery or cotton in alkali
and carbon disulfide to make viscose,
prior to taking the liquid to a cellulose
state via an acid bath. Within a few
years, however, DuPont had invented
machines that enabled the mass
production of cellophane, ensuring a
vast supply for what would become
a booming packaging market. Indeed,
these developments catalyzed
explosive growth of DuPont's sales
of cellophane to food manufacturers
- between 1928 and 1930, sales
of cellophane tripled. By 1938, the
" magical " transparent film accounted
for 10% of DuPont's sales and 25%
of its profits. The product you could
" see right through " had become a
commercial juggernaut.
Cellophane's emergence as a
packaging innovation for the consumer
market coincided with, and
encouraged, the rise of self-service
retailing, particularly of food products.
In the early 20th century, customers
typically purchased fresh foods from
open-air markets, where quality was
uneven and food waste high. Grocers
sold customers canned products,
or fresh foods that were selected
and wrapped by store clerks. The
introduction of cellophane wrapping,
especially when coupled with refrigerated
store shelving, allowed sellers
to present fresh goods in packaging
that connoted cleanliness, enhanced
food safety and quality control, reduced
ambient odors, and allowed
for buyer's easy access without the
involvement of a clerk.
Most significantly, cellophane enabled
consumers to see what they
were buying and to make purchasSHI
FIGURE
1. A 1945 magazine advertisement touts
the transparent property of cellophane biopolymer
ing decisions based on visual inputs
such as colors, textures and evident
freshness. DuPont's own consumer
research found that 85% of food
purchasing decisions were made by
customers visually scanning products
in store. Advertising of the period
encouraged shoppers, bluntly,
to " eye it before you buy it " (Figure
1). And when developments to cellophane
and competing products in
the 1940s ensured that meat could
be wrapped to allow for an optimal
balance between moisture control
and oxygen penetration, the provision
of fresh red meat outside the
butcher's counter further ensured
cellophane's packaging dominance.
This dominance did not survive the
20th century. Cheaper, petroleumbased
films, such as polyethylene for
baked goods and polyvinyl chloride
for meat packaging, gradually ate into
wood-based cellophane's market
share. By the 1980s, production of
cellophane was almost halted. But in
recent years, cellophane production
has enjoyed a modest resurgence.
Its complete biodegradability stands
in contrast with the plastic products
that, in the minds of consumers, fill
landfills, allowing consumers to " eye
it before they buy it, " in a new way. n
Edited by Scott Jenkins
Editor's note: This content is created by the research and curation
team at the Science History Institute (SHI; Philadelphia, Pa.; www.
sciencehistory.org).
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