Laser coloration of coated substrates
View Patent ↗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—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.
1. A record material that is imageable with a laser beam, said material comprising a cellulosic substrate comprising white filler having provided on at least one surface thereof a coating containing a solvent-soluble or disperse-type dye suitable for coloring plastics or polymers,
wherein said dye does not show visible dye specks in the coating layer due to the dye in the coating having an average particle size of less than 50 microns and due to no more than 1% of dye particles in the coating being larger in diameter than 100 microns.
2. The record material of claim 1 , wherein said laser beam is a beam from a CO 2 laser or a YAG laser.
3. The record material of claim 1 , wherein said substrate is paper.
4. The record material of claim 1 , wherein said solvent-soluble or disperse-type dye is selected from the group consisting of monoazo dyes, diazo dyes, anthraquinone dyes, coumarin dyes, quinoline dyes, xanthene dyes, and naphthalimide dyes.
5. A record material that is imageable with a laser beam, said material comprising a cellulosic substrate comprising white filler having provided on at least one surface thereof a coating containing a solvent-soluble or disperse-type dye suitable for coloring plastics or polymers,
wherein the dye is incorporated into the coating in the form of an aqueous-based slurry containing dye particles having an average particle size of 20-80 μm, and wherein said dye does not show visible dye specks in the coating layer due to the dye in the coating having an average particle size of less than 50 microns and due to no more than 1% of dye particles in the coating being larger in diameter than 100 microns.
6. The record material of claim 5 , wherein the slurry comprises the dye, water, and a dispersant, at a low concentration compatible with a coating operation, selected from the group consisting of ionic and nonionic dispersants and mixtures thereof.
7. The record material of claim 6 , wherein the dispersant is a polyalkylene glycol ester, an acrylate, or a urethane.
8. The record material of claim 6 , wherein the slurry further comprises a thickener.
9. The record material of claim 8 , wherein the thickener is carboxymethyl cellulose, hydroxyethyl cellulose, or an acrylate.
10. The record material of claim 1 , wherein the dye is present on the surface of the substrate at a dry on total solid components concentration of 1% or less, thereby being substantially colorless on the surface of the substrate.
11. The record material of claim 1 , wherein the dye is incorporated into the coating in the form of a dry powder having a average particle size of 20-80 μm.