The first step in bottle manufacturing is stretch blow molding. The plastic placed in a mold when its heated.It makes the shape of a long, thin tube. Then pressurized air is put into the mold so the plastic can make the shape.
The mold must be cooled fast. They do this by running water through pipes surrounding the mold. This indirectly cools the mold and plastic. Another way is blowing pressurized air or carbon dioxide directly on the mold and plastic.