Electrocoating composition

A cathodic electrocoating composition comprising:

• an aqueous carrier;
• a film forming binder dispersed in the carrier, wherein the binder comprises an epoxy-amine adduct and a blocked polyisocyanate crosslinking agent;
• a pigment paste;
• hydroxyethyl cellulose having a weight average molecular weight of from about 250,000 to about 1,500,000 Da in an amount of from about 0.075 to about 0.15 percent by weight, based on weight of resin solids of the composition;
• and
• a cationic microgel dispersion having a particle size of from about 500 to about 2000 Angstroms and present in an amount of from about 1.5 to about 2.5 percent by weight, based on weight of resin solids of the composition, the cationic microgel dispersion prepared by dispersing in aqueous medium a mixture of a cationic polyepoxide-amine reaction product containing primary amine groups, secondary amine groups, or mixtures thereof and a polyepoxide crosslinking agent, and heating the mixture to a temperature sufficient to crosslink the mixture to form the cationic microgel dispersion;
• wherein the composition has a cationic microgel dispersion weight solids to hydroxyethyl cellulose weight solids ratio of from about 15:1 to about 25:1 wherein the cathodic electrocoating composition has a pigment to binder weight ratio of from about 0.15:1 to about 0.25:1;
• and wherein the composition provides a synergistic improvement in edge protection and coating appearance with a surface roughness of from about 0.35 to about 0.45 micrometers.