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Color-Changing Inks

(January 2003) posted on Wed Jan 29, 2003

Brighten your bottom line

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By J. Homola

Ink Type Water base Epoxy Plastisol

Substrates paper, plastics glass, wood textiles

Screen mesh 110 thread/in. 110 thread/in. 110-305 thread/in.

Curing air dry 1 hr air dry 7-8 hrs 325°F (use standard plastisol cure procedure)

Ink manufacturers try to control the formulations so that little, if any, color is displayed indoors while achieving maximum color outdoors. This color control can be partially managed by the printer. A thinner ink laydown will affect lower indoor coloration, but will produce less intense outdoor coloration. A heavier ink laydown strengthens the colors both indoors and outdoors. Printers can test to find the balance that works best for them.

Economics of color-changing inks

Whether thermochromic or photochromic, color-changing inks contain highly specialized components that require extraordinarily careful manufacturing techniques. Not surprisingly, their per-gallon costs exceed that of traditional screen-printing inks. In fact, they are quite a bit more expensive. For example, a gallon of standard, UV-curable ink might cost $100-200, while a thermochromic UV ink will run about $800. Depending on the specific application and ink laydown, it typically costs between $0.005-0.02/sq in. of coverage of thermochromic UV ink.

Remember, however, that these inks impart a great deal more value to a printed substrate. The cost of the ink, as well as additional profit, can easily be incorporated into the price of the part. Take, for example, a gallon of photochromic plastisol ink, which costs four times the price of a regular plastisol. Normally, a square inch of coverage with a conventional plastisol costs about $0.0015. Depending on the specific design, a photochromic design may cost an additional $0.20 per garment. The good news is that the photochromic shirt exacts a $2-4 premium, simply because of the color-changing ink. That's adding value!

Color-changing materials offer fresh opportunities for additional profits and product line expansions. They are not difficult to work with and can be used in an ever-widening range of applications--many of which are still in the imaginations of some creative and enterprising screen printers. They are certainly worth a try.

About the author

Timothy J. Homola is the President and founder of Color Change Corporation, Addison, IL. The company, which was founded in 1992, specializes in color-changing materials, products, and technology. Homola has a bachelor of science degree in chemical engineering from the University of Illinois and a master's degree in management from the Kellogg School at Northwestern University.


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