Eosin, a coloring color commonly used in color-changing lipsticks, is an acid dye with a typical name of solvent red 43, additionally referred to as tetrabromofluorescein or tetrabromofluorescein in English. It will certainly produce a color change according to the adjustment of pH worth. When the pH value is above 4, the solvent red 43 in the color-changing lipstick becomes crimson.
Although the lips are neutral, saliva is normally weakly alkaline. When saliva touches the lips, the lips also end up being weakly alkaline, that is, the pH worth is above 7. The color-changing lipstick constructed from eosinic acid pigment has a pH value of 3. When the lipstick including solvent red 43 is applied on the lips, it will transform color. Eosin pigment serves as an acid-base sign!
Friends who have used PH test paper know that when the PH value is evaluated on the PH test paper, the colors generated by different PH values are different. Place on a color-changing lipstick, as well as the make-up result will be different.
Why can color-changing lipsticks change into multiple colors?
For example, there are several different color-changing lipsticks, including pink and orange. This is because the coloring dye eosin, also known as tetrabromofluorescent yellow or tetrabromofluorescein, has different molecular structures, so the colors produced are also different. , but it only changes in the color system of red.
Does color-changing lipstick have anything to do with temperature?
Many manufacturers who sell color-changing lipsticks on the market claim that color-changing lipsticks are temperature-changing lipsticks, that is, they have different colors according to different temperature changes. In fact, the main principle is the pH value, but it also has a certain relationship with the temperature. But it’s just a matter of time. The higher the temperature, the faster the discoloration will be, but the final color will be the same. For example, if black turns pink, it takes 30 seconds if the temperature is high, and it takes 1 minute if the temperature is low.