Color change temperature of thermochromic pigment

Color change temperature of thermochromic pigment

1. Sensitive temperature change color temperature

In fact, the color change temperature of thermochromic pigments is not a temperature point, but a temperature range, that is, the temperature range (T0～T1) included from the start of the color change to the end of the color change. The width of this temperature range is generally 4~6℃. Some varieties with higher discoloration accuracy (narrow range varieties, denoted by "N") have a narrow discoloration temperature range, only 2~3℃.

Generally, we define the temperature T1 corresponding to the completion of the discoloration during the constant heating process as the discoloration temperature of the thermochromic pigment. Pearlescent pigments, color changing pigments, fluorescent pigments

2. Number of cycles of temperature change color:

Take a small amount of the tested color-changing pigment, mix it with 504 epoxy glue, scrape the sample (thickness 0.05-0.08 mm) on white paper and let it stand at room temperature above 20°C for one day. Cut a 10×30 mm paper pattern. Take two 600 mL beakers and fill them with water. The water temperature is 5～20℃ above the upper limit (T1) of the color change temperature range of the tested sample and not less than 5℃ below the lower limit (T0). (For the RF-65 series ink, the water temperature is set as T0=35℃, T1=70℃ ) And keep the water temperature. The sample is immersed in two beakers in turn, and the time to complete each cycle is 3 to 4 seconds. Observe the color change and record the reversible color cycle number (usually, the color change cycle number of the thermal decolorization series is greater than 4000-8000 times).