The making of a milk jug

Published Oct 31, 2011 at 6:00 am (Updated Mar 19, 2012)

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1. When you drain that quart of chocolate milk from Borden or Kleinpeter down to the last drop, the last thing on your mind is the milk jug. But there's a story behind that milk jug that starts right here on the corridor—at ExxonMobil's Baton Rouge Polyolefins Plant (BRPO). Plastic containers that hold liquids like milk are made with a special type of plastic called high-density polyethylene (HDPE). This plastic is made and tested at BRPO.

2. Lab technicians at BRPO "blow mold" sample containers in their lab and test them for molding performance and other key quality attributes. The HDPE that is used in milk jugs is also used in other liquid food applications such as bottles for water and juices, including small, single-serve containers.

3. Most of the HDPE made at BRPO is shipped to custom molders, but some of it is shipped to local dairies such as Winn Dixie in Hammond and Kleinpeter Farms in Baton Rouge. To blow mold a milk jug, plastic is fed to an extruder and melted. Then the melted plastic is pushed into a mold where air is blown in to inflate it into the shape of a bottle. The mold is simultaneously cooled to harden the outside of the jug. Then, the jugs are sent to a filling line.