Ultraviolet cured coating method to provide stone chip resistance

摘要

A method of providing a stone chip-resistant finish to the undersurface of an automobile is disclosed in which the undersurface is coated with a cationically initiated liquid mixture of cationically curable polyepoxide, polyhydric alcohol, and a photoinitiator for an ultraviolet-activated cationic cure. The liquid mixture is applied at a resin solids content of at least about 50% and in a thickness to provide a cured coating of at least 2 mils thick, and the wet coating is cured by exposing it to ultraviolet light. The automobile undersurface is desirably primed with a cross-linked amine-functional polymer primer, and the coating includes from 1% to 8% of a finely divided silica which prevents running but does not interfere with the ultraviolet cure.