The Lubrizol Corporation announced that it has signed a definitive agreement to purchase Noveon International, Inc. in a transaction valued at $1.84 billion. The acquisition is subject to regulatory approval and is expected to close within three months.      The addition of Noveon, a privately-held Cleveland, OH-based specialty chemical company with $1.2 billion in revenues for the last 12 months, will create a combined company with approximately $3.2 billion in annualized revenues. It will co...