Method and composition for indicating the presence of chrome-free pretreatments on metal surfaces by fluorescence
AssigneeBulk Chemicals, Inc.
InventorJose B. Rivera
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Abstract
A method and composition for indicating the presence of a chrome-free pretreatment for improving the paint adhesion and corrosion resistance of a metal surface. The presence of the pretreatment is indicated by adding a compound to the chrome-free pretreatment which causes the pretreatment to fluoresce under an ultraviolet light. The additive which causes the pretreatment to fluoresce under an ultraviolet light is an ultraviolet tracer, such as a stilbene or a coumarin derivative, and the method according to this invention includes exposing the coated metal to ultraviolet light.
Claims4
A method for indicating the presence of a chrome-free pretreatment on a metal Surface comprising:
- forming a mixture of a chrome-free pretreatment and an ultraviolet tracer, which are at least dispersible and soluble in water, said pretreatment comprising a polymeric resin and a group IV-B compound;
- and said ultraviolet tracer comprising a fluorescent whitening agent selected from the group consisting of at least one of a stilbene derivative and at least one of a coumarin derivative;
- applying said mixture to a metal surface to form a coated metal surface;
- and
- exposing said coated metal surface to ultraviolet light, wherein said tracer exhibits a color upon exposure to ultraviolet light.
Dependencies are inferred from the claim text.