How plastic wrap is made

Plastic wrap clings to smooth surfaces with no glue at all, using a film only about 10 micrometers thick.

stations: 6
things upstream: 42
raw sources: 11
steps from the ground: 9

The short version

Plastic wrap is a plastic resin, most often PVC or polyethylene, melted and pushed through a die into an extremely thin film. The film is cooled, stretched to thickness, slit to width and wound onto cardboard tubes. It sticks to smooth surfaces by itself, so no adhesive is needed.

Blend the resin

PVC resin is mixed with plasticizers that make it soft and clingy. Cheaper wraps start from low-density polyethylene instead, often with a second polyethylene added to make it stick better and resist tearing.

Goes in
PVC Polyethylene
Melt in the extruder

Pellets feed into an extruder, where heat and the turning screw melt them into an even plastic melt.
Form the thin film

Cast lines push the melt through a flat die onto chilled rolls, and the fast cooling keeps the film clear. Blown lines push it through a ring die and inflate a bubble. PVC wrap is usually cast, and polyethylene wrap goes either way.
Stretch to thickness

The film is stretched and gauged until it reaches its target thickness. Household wraps keep getting thinner because they need very little stretch in use.
Slit and wind

Edges are trimmed and the wide film is slit to the width of a roll, then rewound onto cardboard cores.

Goes in
Cardboard
Box with a cutting edge

Each roll goes into a carton with a serrated edge that tears it to length.

Goes in
Cardboard

End of the linePlastic wrap Next it goes into aa battery, microwave popcorn, candy cane.

Worth repeating

Common plastic wrap is about 12.7 micrometers thick, and most brands on shelves are now 8, 9 or 10 micrometers.
Wrapping premature babies in plastic wrap right after birth has been studied as a way to keep them warm on the way to intensive care.