Using heat and pressure in a process called “thermal cracking,” ethane and propane in Naptha turn into short chain hydrocarbons called monomers: ethylene and propylene.

Monomers are next turned into longer, repeating chains called polymers: polyethylene and polypropylene.

Millions of these polymers are turned into a plastic mass and turned into pellets. The polymers are fed into an extruder where it is heated, fed into a pipe, and turned into long tubes of plastic. Once cooled, the long tubes are cut into small pellets.

These pellets are shipped to factories. Each factory will melt and mold the pellets into their plastic product.