Patent ID: 7144526

Claim:
A flexible conductive primer coating composition containing solvents and 40–75% by weight of film forming binder and pigments in an overall pigment to binder weight ratio of about 1:100 to 200:100; wherein the binder comprises (A) a polyester copolymer having linear segment with hydroxyl groups that has a hydroxyl number of about 15–300 and a number average molecular weight of about 300–3,000 and branched segments that have hydroxyl groups and have a hydroxyl number of about 175–300 and a number average molecular weight of about 500–2,000 and are attached to linear segment by esterification of the hydroxyl groups with a diacid or an anhydride and (B) an organic polyisocyanate crosslinking agent; and wherein the pigments comprise electrically conductive pigments in a pigment to binder weight ratio of about 1:100 to 130:100, and the electrically conductive pigments consist essentially of a combination of graphite and carbon black pigments in a graphite to carbon black weight ratio of about 120:1 to 1:1, and the composition forms a coating having a surface conductivity of at least 100 Ransburg units when cured at ambient temperatures or low bake temperatures.