During the past few years, many of the longtime leaders who made Sun Chemical what it has become today have stepped down. Most recently, Kenneth C. Collins, senior vice president, corporate purchasing and supply chain management, retired at the end of March. During his 39 years at Sun Chemical, Mr. Collins held a wide variety of leadership positions, but it was his role as the leader of the company’s purchasing department that earned him the most notice. Since 1989, Mr. Collins had been primari...