LASER MARKING OF PIGMENTED SUBSTRATES

摘要

A method for producing fluorescent markings on a substrate which method comprises exposing parts of a composition comprising a polymer and an organic pigment to a heat source, such as laser radiation, to produce a fluorescent 5 markings which are are not discernable when viewed under ambient visible light but readily apparent under UV light is disclosed. The method produces novel compositions wherein a fluorescent form of a pigment is present at a higher concentration in defined domains relative to the remainder of the composition. The novel polymer composition is particularly useful in security marking applications.