Dunkin’ Brands Group Inc., operator of the Dunkin’ Donuts coffee chain, is seeking to raise as much as $460.6 million in its initial public offering, 15 percent more than the company planned in May.   Dunkin’ Brands, which was taken private in 2006 by Bain Capital LLC, Carlyle Group and Thomas H. Lee Partners LP, is offering 22.3 million shares for $16 to $18 each, the company said in a filing with the U.S. Securities and Exchange Commission today. Dominic Chu reports on Bloomberg Television’s "InBusiness With Margaret Brennan."