Plastic manufacturing process

First, crude oil and natural gas are extracted, and then sent to refineries to extract many substances, including the main components of plastics, that is, ethane is extracted from oil, propane is extracted from natural gas, ethane and Propane is sent to a cracking plant to be broken down into molecules, ethane is used to make ethylene, and propane is used to make propylene, and then a catalyst is added to combine the molecules to form a resin polymer. Because of this structure, plastics are easy to shape under high temperatures and pressures. 

Polymerization turns ethylene into polyethylene and propylene into polypropylene. These resins are melted and cooled, and then cut into plastic raw material pellets. The plastic pellets are sent to factories and heated to make various plastic products.