Thermochromic Leuco Dye
Leuco Dyes change color with changes in temperature. LDs are reversible, meaning they change color back and forth as the temperature fluctuates. It takes about a 5ºF (3ºC) temperature change for the LD to change color.
Activation temperature points range from low refrigeration type temperatures through normal body temperatures to high temperatures that exceed the pain threshold.
Leuco Dye Products are available in a wide variety of colors, temperatures and forms, which include powder, slurry, water and solvent based ink, epoxy, and master batch.
LDs are more robust and less expensive than liquid crystals and can be used in a wider range of inks, plastics, etc. Because LDs are not very sensitive, they do not make accurate thermometers, but are used in applications where larger temperature differences are present or when temperature accuracy is less important. A LDs life span is adversely affected by sunlight, extreme temperatures and contact with aggressive solvents.
Applications are only limited by the imagination and include quality control, advertising and promotional applications, product labeling, toys, game pieces, and packaging. LDs give life to materials and printing, offering the opportunity to engage and excite your audience with a graphic or component that changes color when stimulated by temperature. Great for manufacturing and process control where a visual indicator will reinforce temperature management.
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