Process for coating objects in a flow-coater

摘要

Objects are flow-coated with a water-dilutable coating agent comprising a binder, water and optionally an organic solvent by a process wherein the quantitative ratio of binder to solvent to water in said coating agent is maintained substantially constant throughout thereby maintaining the solids content and the viscosity of said coating agent substantially constant. The Specification includes long lists of suitable binders and organic solvents. The apparatus for carrying out the process comprises (Fig. 1) a container for the coating agent, a container 2 for the additive composition for maintaining constant viscosity and an automatically controlled valve 3. The object to be coated 5 is introduced into the spray chamber 4 by a transport device 9 such as a chain attached to a roller 8 or other sliding device moving on a rail 6. Spray nozzles 7 coat the object which is then transported in the direction of the arrow a into the chamber 10 when excess coating material drips off on to the draining surface 23 and flows back into the container 1. The ratio of binder to solvent to water is maintained constant by measuring the viscosity or concentration of the composition. Other methods are also listed. Arrangements are described and illustrated whereby marring of the coated article in the drying chamber 10 by condensed droplets of the coating mixture is prevented.