Westlake Chemical Increases Proposal to Acquire Axiall Corporation to $23.35 Per Share in Cash and Stock

-- Axiall's Board Summarily Rejects Revised Proposal -- Revised Proposal Represents Premium of Over 143% to Axiall Closing Share Price Prior to Initial Proposal and an Increase of Approximately 17% to Initial Proposal HOUSTON , April 4, 2016 /PRNewswire/ --  Westlake Chemical Corporation (NYSE: