Appleton Papers Inc.

Pauline Ozoemena Ukpabi

Record material imageable with a laser beam. The material is a substrate such as paper or polyolefin film having provided on at least one surface thereof a coating containing a solvent-soluble or disperse-type dye suitable for coloring plastics or polymers. Typical solvent-soluble and disperse-type dye include monoazo dyes, diazo dyes, anthraquinone dyes, coumarin dyes, quinoline dyes, xanthene dyes, and naphthalimide dyes. The record material does not show visible dye specks in the coating layer on the substrate because the dye has a very small average particle size&#x2014;less than 50 microns. No more than 1% of the dye particles are larger than 100 microns. Also, method for imaging a substrate using heat energy by applying heat energy to the described record material to bring about a temperature in the coating greater than the melting temperature of the dye, causing color to become visible in the record material.

Laser coloration of coated substrates

A rapidly reversing authenticity indicator for substrates such as secure documents, tags and labels is described. The authenticity indicator comprises a substrate having provided thereon a coating of a colorless chromogenic material, a binder material and optional pigment. An applicator is provided containing a developer material solution for the colorless chromogen. In one embodiment, the developer material solution is preferably an organic acid of five carbons or less and is selected to have a molecular weight of 102 or less, a pH of less than 5, and preferably positive vapor pressure. The coated substrate when contacted with the developer material in the applicator develops an intense color that persists momentarily rapidly reverting to substantially a colorless or pale form to provide a visual indication of authenticity without permanent discoloration of the substrate or inadvertent coloration or undue false positives.

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Appleton, WI, United States of America

Pauline Ozoemena Ukpabi