How plastic is made

Over 400 million metric tons of plastic were made in 2023, and more than half of all plastic ever produced came after 2004.

stations: 5
things upstream: 7
raw sources: 3
steps from the ground: 4

The short version

Plastic is made of long chain molecules called polymers, built by linking small repeating units called monomers. Plants make the monomers from oil or gas, join them into polymer, and add other ingredients. The product is melted into pellets, which factories mold, extrude or press into finished shapes.

Make the building blocks

Oil or natural gas is turned into small hydrocarbon molecules that can be strung together. Ethylene and propylene are the best known.

Goes in
Naphtha Natural gas
Link them into chains

Monomers join into polymer chains of thousands of repeating units. The type of monomer decides which plastic comes out.

Goes in
Ethylene Propylene
Blend in additives

Polymer is mixed with other ingredients that give it color, strength or flexibility. Most plastics are polymer plus additives.
Cut into pellets

The melt is extruded in strands and chopped into small pellets. Pellets are easy to ship by the truckload.
Mold, extrude or press

Factories reheat the pellets and form them into films, fibers, pipes, bottles and boxes. A thermoset, in contrast, can melt and take shape only once.

End of the linePlastic Next it goes into duct tape, led, aa battery and 35 more.

Worth repeating

About 9.2 billion metric tons of plastic were estimated to have been made between 1950 and 2017.
Roughly 80 percent of plastic is commodity plastic chosen for low cost.
Packaging takes about a third of all plastic.