KINGSPORT — Eastman Chemical Co. remains in an acquisition mindset after buying four companies during 2014, Eastman Chairman and CEO Mark Costa advised more than 200 business people and elected officials at a Regional Leaders Breakfast on Tuesday.“Our growth is going to be a mix of organic growth which we’ve always done, and acquisitions that could be up to half of our portfolio going forward,” Costa said of the business strategy for Eastman, a $9.5 billion global specialty chemical company based in Kingsport.The centerpiece of those acquisitions last year was taking over another specialty chemical company, Taminco Corp., for a total of $2.8 billion in cash and assumed debt.The move upped Eastman’s profile and sales in agricultural and personal care markets.All total, the acquisitions brought in 1,400 new members to push the company’s worldwide employment level to 15,000, according to Costa.“What we’ve discovered is we’re really, really good at integration,” Costa said when asked about the strategy during a short question-and-answer session with the MeadowView Marriott audience after his prepared remarks.