MULTI-STAGE PROCESSES FOR DRYING AND CURING SUBSTRATES COATED WITH AQUEOUS BASECOAT AND A TOPCOAT

摘要

A multi-stage process for drying and curing substrates coated with liquid waterborne basecoat and a topcoat includes: (a) applying a liquid waterborne basecoating composition to the substrate surface; (b) exposing the basecoati ng composition to air having a temperature ranging from ambient to about 40~ C for a period of about 30 seconds to volatilize at least a portion of volatil e material from the liquid basecoating composition, the velocity of the air at the surface of the basecoating composition being about 0.3 to about 1 meter per second; (c) applying heated air to the basecoating composition for a period ranging from about 30 to about 45 seconds, the velocity of the air at the surface of the basecoating composition ranging from about 1.5 to 15 mete rs per second, the air having a temperature ranging from about 30~ C to about 9 0~ C; (d) applying infrared radiation and heated air simultaneously to the basecoating composition for a period of ranging from about 30 to 45 seconds, the velocity of the air at the surface of the basecoating ranging from about 1.5 to 5 meters per second, the air having a temperature ranging from about 30~ C to about 60~ C, such that a sufficiently dried basecoat is formed upon the surface of the substrate; (e) applying a topcoating composition over the basecoat;and (f) simultaneously curing the basecoating composition and the topcoating composition together.