By Patrick Raleigh, UT On-line/news editorNorthfield, Illinois-Stepan Co.'s polyurethane polyols business was the strongest performer in the group's polymer business, which reported a 'significant' year-on-year increase in first quarter earnings. Polymer earnings lifted on an 18-percent increase in volumes overall. The unit further benefited from the establishment of Stepan's new polyester polyols reactor in Germany last year, the company said. Stepan's Polymers business is now "on track for improved volume and earnings for the rest of 2004, according to F. Quinn Stepan the company's chairman and CEO, in a 27 April statement."Raw material prices have increased significantly over the past six months. Our ability to maintain our margins will be a critical element of our success in 2004," said the Stepan boss. The company has recently announced polymer price increases effective 1 April 1, he noted. For the group as a whole, Stepan reported 76-percent rise in net earnings on sales of $221 million, 18 percent higher than in the first quarter of 2003."Improved sales mix from higher margin specialty products coupled with overall increased sales volume led to the improvement in earnings," said Stepan."