Electrocoating bath control

Claim 1

IN A COATING PROCESS WHICH COMPRISES IMMERSING AN ELECTRICALLY CONDUCTIVE OBJECT IN AN AQUEOUS COATING BATH HAVING A FIRST ELECTRODE SPACED APART FROM SAID OBJECT AND IN ELECTRICAL CONTACT WITH SAID BATH AND A FILM-FORMING POLYCARBOXYLIC ACID RESIN COMPRISING COATING MATERIAL DISPERSED IN SAID BATH IN A MANNER SUCH THAT SAID BATH COMPRISES A CONTINUOUS AQUEOUS PHASE AND A RESIN COMPRISING DISPERSE PHASE, PROVIDING SAID FIRST ELECTRODE WITH A NEGATIVE ELECTRICAL POTENTIAL RELATIVE TO SAID OBJECT THEREBY PROVIDING A DIRECT CURRENT FLOW OF ELECTRICAL ENERGY THROUGH SAID BATH AND BETWEEN SAID FIRST ELECTRODE AND SAID OBJECT WHICH ELECTRICALLY INDUCES DEPOSITION OF SAID COATING MATERIAL UPON SAID OBJECT AND FORMS A FILM OF SAID COATING MATERIAL ON SAID OBJECT, AND WITHDRAWING THE RESULTANT COATED OBJECT FROM SAID BATH, THE IMPROVEMENT WHICH COMPRISES MAINTAINING IN SAID BATH THE COMBINATION OF A FIRST SOLVENT THAT IS MISCIBLE WITH SAID RESIN AND HAS A SOLUBILITY IN WATER AT ABOUT 25*C. NOT SUBSTANTIALLY IN EXCESS OF ABOUT 10 WT. PERCENT AND A SECOND SOLVENT THAT IS MISCIBLE WITH SAID RESIN, ESSENTIALLY INSOLUBLE IN WATER, AND IN WHICH SAID FIRST SOLVENT IS SIGNIFICANTLY SOLUBLE, AND MAINTAINING THE CONCENTRATION OF SAID SECOND SOLVENT IN SAID BATH AT A LEVEL SUFFICIENT TO MAINTAIN THE CONCENTRATION OF SAID FIRST SOLVENT IN SAID AQUEOUS CONTINOUS PHASE BELOW A PREDETERMINED LEVEL.