Abstract: A method of making a solvent based ink formulation which includes a thermochromic pigment, wherein the pigment being formed of microcapsules, includes drying a slurry that contains the pigment to a solids concentration between 70% and 99%, mixing the dried slurry in an appropriate mixing base, and adding any desired ink components to the base formulation. Each microcapsule contains a reversible thermochromic coloring material which exhibits a visible change in color between a first color state and a second color state in response to a change in temperature. Acceptable ink components include a gel vehicle, a free flow vehicle, a drying agent, a lithographic varnish, an ink wax, a polyester vehicle, a polyglycol solvent, a colloidal dispersion resin water, and a defoamer.

Abstract: A method of making a solvent based ink formulation which includes a thermochromic pigment, wherein the pigment being formed of microcapsules, includes drying a slurry that contains the pigment to a solids concentration between 80% and 95%, mixing the dried slurry in an appropriate mixing base, and adding any desired ink components to the base formulation. Each microcapsule contains a reversible thermochromic coloring material which exhibits a visible change in color between a first color state and a second color state in response to a change in temperature. Acceptable ink components include a gel vehicle, a free flow vehicle, a drying agent, a lithographic varnish, an ink wax, a polyester vehicle, a polyglycol solvent, a colloidal dispersion resin, water, and a defoamer.

Abstract: The present invention comprises a series of discoveries related to the problems associated with formulations that destroy the color change properties of thermochromic encapsulated dyes. One aspect of the present invention is the discovery of a method of correcting these formulations to allow the addition of thermochromic dyes. Certain solvents destroy the dye, therefore any aldehydes, ketones, and diols, and most aromatic compounds should be removed from the formulation and if needed they should be replaced with solvents preferably having a large molecular weight (i.e. greater than 100 and low reactivity). Secondly, the formulation should be adjusted to be neutral (i.e. 6.5-7.5 pH) or have a low acid value. These two adjustments will allow the thermochromic dyes to added to the formulation without a loss of its color change properties.