The tolerance of temperature-sensitive color-changing pigments to different solvents is different. Soaking in some solvents for 6 months will not affect their color-changing performance, but other solvents can erode the surface layer of microcapsules and penetrate into them within several hours to weeks, so that the color-changing performance of pigments will fade or even disappear completely. After the solvent volatilizes, some of this discoloration can be partially recovered, and some are completely unrecoverable. Generally speaking, solvents containing less than 3 carbon atoms are more destructive to the corrosion of color-changing pigments, while solvents containing more than 6 carbon atoms have little effect on pigments. In addition, the corrosion of solvents will be more obvious at higher temperatures.
Based on the above reasons, the following measures should be taken when preparing inks and coatings:
-Try to use less or no alcohol solvents below C4, and replace them with other solvents. For example, cyclohexanone can be used instead of propanol.
-When solvents such as propanol must be used, ink (paint) should be prepared as needed to avoid storage.
Because our color-changing pigments are easily dispersed in the resin solution, we can distribute all ink (paint) groups except color-changing pigments, add a specified amount of color-changing pigments before printing, and then add them into Mo Dou to start printing. It is also possible to prepare inks (including color-changing pigments) other than propanol and isopropanol, add a specified amount of the above solvent just before use, and start printing after stirring evenly. Be careful not to mix too much ink at a time, and do not store it as you use it.
Special note: the diluent/mixed solvent commonly used in the ink industry and some resin solutions may contain ethanol, acetone, propanol and other components that damage the performance of color-changing pigments. Even if the content of harmful components is very small, it will have a serious impact. Select the appropriate ink blending oil and ink blending method. Some ink blending oils contain chemical components such as phosphate or chlorine/bromine, and once a small amount of microcapsule pigments are damaged during ink blending, these substances will have an irreversible color reaction with those damaged pigments, which will obviously increase the residual color. Therefore, the use of this ink blending oil should be avoided.