Silane-terminated polycarbodiimide primers and composite coatings therefrom

Claim 1

An aromatic polymer containing at least 1% by weight of carbodiimide groups, said polymer selected from the formulae: R.sup.1 --Z--N═C═N--R.sup.2).sub.b (N═C═N--R.sup.3).sub.c (N═C═N--R.sup.4).sub.d (N═C═N--Z'--R.sup.5 (I) wherein R 1 and R 5 are independently selected from --Si(OR 6 ) 3 wherein R 6 is independently selected from alkyl or phenyl and has no more than 10 carbon atoms, Z and Z' are independently aliphatic, aromatic, or mixed hydrocarbon which may have no more than one O or S atom in the backbone for 2 carbon atoms and having fewer than 20 carbon atoms R 2 and R 4 are independently divalent aromatic groups bonded to the adjacent N atom of the exterior carbodiimide directly from an aromatic ring, said aromatic group being free of isocyanate reactive groups and having fewer than 20 carbon atoms R 3 is a divalent aliphatic, aromatic, or mixed hydrocarbon group free of isocyanate reactive groups, having fewer than 20 carbon atoms b is > 0 c is 0 or 1 d is 0 or a whole integer and b+c+d is at least 1 and no more than 50, ##STR16## wherein R 1 , R 2 , R 4 , R 5 , Z, Z', and b are as defined above b+e = at least 2 and no more than 50 R 7 is the hydrogen free residue of a di-(active hydrogen) terminated compound, said residue having no isocyanate reactive groups and wherein R 2 and R 4 are also directly attached to the nitrogen atom of the adjacent ##STR17## group from an aromatic ring, ##STR18## wherein R 1 , R 2 , R 5 , Z and Z' are as defined above, and f is at least 2 and no more than 50, and ##STR19## wherein R 1 , R 2 , R 5 , Z and Z' are as defined above, and g is at least 2 and no more than 50, and Y is the residue of a primary amine terminated hydrocarbon formed by the removal of a hydrogen from the amine group, with the hydrogen free residue portion of Y forming a bond with the adjacent group ##STR20##