Plastic bags, also called “poly bags,” are one of those modern
conveniences we take for granted. But 60 years ago, no one ever
considered the question, “Paper or plastic?” Back then, people also
managed to get by without Ziploc® bags or dry cleaner bags.
This was because the
technology for creating
polyethylene film didn’t
emerge until the 1940s during
World War II. And the
methods to create plastic bags
from polyethylene film weren’t
developed until the 1950s.
The most common way to
produce poly bags is by blown
film extrusion, also called the
“tubular film process.” In a
moment, you’ll see how it got
this name.
Plastic bags are made from
polyethylene. During
processing, the polyethylene
might be treated with any
number of additives, such as