Leading global chemicals, specialty materials, and seed producer DuPont plans to issue senior unsecured notes. We have assigned an 'A' senior unsecured debt rating to these notes and affirmed all our other ratings on DuPont, including the 'A/A-1' corporate credit rating. The negative outlook reflects the deterioration in DuPont's key credit metrics during the recent economic downturn and points to the possibility that the post-recession financial profile might not strengthen sufficiently to support the current ratings. NEW YORK (Standard&Poor's) Nov. 4, 2009--Standard&Poor's Ratings Services said today that it assigned its 'A' senior unsecured debt rating to E.I. DuPont De Nemours&Co.'s proposed offering of senior unsecured notes maturing in 2015 and 2020. Standard&Poor's