In an apparent move to focus its business on metal packaging, Ball Corp. has sold its plastics packaging business to Amcor Ltd. for $280 million.

The sale of Ball’s Plastics Packaging, Americas, unit involves plants in five states that produce polypropylene bottles and polyethylene terephthalate (PET) bottles and preforms.

For the 12 months ending in March, Ball’s plastics business amounted to $589 million in sales and $10 million in earnings. According to Ball’s most recent 10-K, plastics packaging represented 9% of the company’s net sales in 2009. The company estimates that the 5 billion PET bottles it shipped in 2009 represents 8% of the U.S. total.

The transaction is expected to close in the third quarter of 2010, pending regulatory approval.

This is the biggest sale of plastic rigid packaging capacity since Owens-Illinois sold its plastics packaging business to Rexam PLC for $1.8 billion in 2007.