The disclosure relates to methods for coloring keratinous substrates using solubilized vat dyes, as well as compositions and kits suitable for carrying out the methods. The disclosure also relates to novel solubilized vat dyes.

The disclosure discloses a method of preparing electric and temperature dual-control bi-stable color-changing dyes and microcapsules, belonging to the technical fields of fine chemicals and materials science. According to the disclosure, after an electrolyte, a leuco dye and an organic solid material are mixed according to 1:(2-10):(15-50), a series of electric and temperature dual-control bi-stable color-changing dye compounds having a color change temperature range of −5° C. to +80° C. can be prepared. The dye compounds change color under cooperative control of electricity and temperature, and can be continuously stable at a certain color change state according to different conditions, and finally achieve controllable color change conditions and controllable color change stable states. When being driven by voltage and temperature, the dual-control bi-stable color-changing microcapsules prepared according to the disclosure achieve controllable color change performance and color change stable states, and have the driving voltage being lower than 10 V (much lower than the human body safety voltage 36 V).

The disclosure discloses a method of preparing electric and temperature dual-control bi-stable color-changing dyes and microcapsules, belonging to the technical fields of fine chemicals and materials science. According to the disclosure, after an electrolyte, a leuco dye and an organic solid material are mixed according to 1:(2-10):(15-50), a series of electric and temperature dual-control bi-stable color-changing dye compounds having a color change temperature range of −5° C. to +80° C. can be prepared. The dye compounds change color under cooperative control of electricity and temperature, and can be continuously stable at a certain color change state according to different conditions, and finally achieve controllable color change conditions and controllable color change stable states. When being driven by voltage and temperature, the dual-control bi-stable color-changing microcapsules prepared according to the disclosure achieve controllable color change performance and color change stable states, and have the driving voltage being lower than 10 V (much lower than the human body safety voltage 36 V).

The present disclosure is drawn to an electronic device housing that can include a heat sensitive coating and a second heat sensitive coating applied to an electronic device housing. The heat sensitive coating or portion thereof can include a thermochromatic colorant having a color-changing activation temperature, and the second heat sensitive coating or portion thereof can include a second thermochromatic colorant having a second color-changing activation temperature. The color-changing activation temperature can be a temperature from 30° C. to about 100° C., and the second color-changing activation temperature can be at least 5° C. greater than the color-changing activation temperature.

The present disclosure is drawn to an electronic device housing that can include a heat sensitive coating and a second heat sensitive coating applied to an electronic device housing. The heat sensitive coating or portion thereof can include a thermochromatic colorant having a color-changing activation temperature, and the second heat sensitive coating or portion thereof can include a second thermochromatic colorant having a second color-changing activation temperature. The color-changing activation temperature can be a temperature from 30° C. to about 100° C., and the second color-changing activation temperature can be at least 5° C. greater than the color-changing activation temperature.

The present disclosure is drawn to an electronic device housing that can include a heat sensitive coating and a second heat sensitive coating applied to an electronic device housing. The heat sensitive coating or portion thereof can include a thermochromatic colorant having a color-changing activation temperature, and the second heat sensitive coating or portion thereof can include a second thermochromatic colorant having a second color-changing activation temperature. The color-changing activation temperature can be a temperature from 30° C. to about 100° C., and the second color-changing activation temperature can be at least 5° C. greater than the color-changing activation temperature.

The present disclosure is drawn to an electronic device housing that can include a heat sensitive coating and a second heat sensitive coating applied to an electronic device housing. The heat sensitive coating or portion thereof can include a thermochromatic colorant having a color-changing activation temperature, and the second heat sensitive coating or portion thereof can include a second thermochromatic colorant having a second color-changing activation temperature. The color-changing activation temperature can be a temperature from 30° C. to about 100° C., and the second color-changing activation temperature can be at least 5° C. greater than the color-changing activation temperature.

A temperature sensor, and methods of making and using such a temperature sensor, whereby the temperature sensor includes a reversible thermochromic color-changing system having a dye, a developer, and a solvent. Upon exposure to a preselected temperature threshold, association or disassociation of the dye and the developer results in a visible color change. Further, the color-changing system includes a color-memory property which facilitates retention of the color change to effectively record exposure to the temperature threshold.

A temperature sensor, and methods of making and using such a temperature sensor, whereby the temperature sensor includes a reversible thermochromic color-changing system having a dye, a developer, and a solvent. Upon exposure to a preselected temperature threshold, association or disassociation of the dye and the developer results in a visible color change. Further, the color-changing system includes a color-memory property which facilitates retention of the color change to effectively record exposure to the temperature threshold.

An aerosol generating article is provided, including a combustible carbonaceous heat source; an aerosol-forming substrate; and a thermal indicator provided on an outer surface of the aerosol-generating article downstream of the combustible carbonaceous heat source. The thermal indicator includes at least one reversible thermochromic material that undergoes a first reversible visible colour change when a temperature of the thermal indicator rises to a first switching temperature and a second reversible visible colour change when a temperature of the thermal indicator falls to a second switching temperature. The first switching temperature is below about 80 C. and the second switching temperature is lower than or equal to the first switching temperature.