May 20, 2008. /Lesprom.com/. Constantia Packaging AG is acquiring the remaining 40 % of the shares in Duropack AG, Euwid pulp and paper informed. By taking over the shares hitherto held by Smurfit Kappa AG, Constantia Packaging becomes the sole shareholder in Duropack. The Irish Jefferson Smurfit Group had held 40 % of the Duropack shares since taking over Interwell AG. The other 60% was already owned by Constantia Packaging. After the merger of Jefferson Smurfit Group and Kappa Packaging, the two companies found themselves increasingly in direct competition with each other in eastern and southern Europe. The executive bodies of both groups therefore decided to break up the common shareholder structure in the interests of all shareholders.