Temperature warning indicator for a handheld lighter

A handheld lighter for igniting a combustible material comprising:

• an ignition mechanism for generating a heat source;
• an actuating means for activating the ignition mechanism;
• a metallic shield positioned adjacent to the ignition mechanism and at a distance to the ignition mechanism such that the metallic shield is heated by the heat source when the handheld lighter is operated;
• and
• a housing comprising the ignition mechanism, the actuating means and the metallic shield;
• wherein the metallic shield comprises a thermochromic coating comprising:
• (a) an electron-donative organic compound (component (a)),
• (b) an electron-accepting compound (component (b)), and
• (c) a reaction medium enabling a reversible electron transfer reaction between the components (a) and (b) above the melting or softening point of the reaction medium (component (c));
• and
• wherein the thermochromic coating is configured to reversibly change color in response to an increase of the temperature of the metallic shield to a first temperature of about 60° C. or above and to reversibly change color in response to a decrease of the temperature of the metallic shield to a second temperature which is about 0 to about 20° C. below the first temperature.

A method of using a thermochromic coating as a temperature warning indicator for a handheld lighter for igniting a combustible material;

• wherein the handheld lighter for igniting a combustible material comprises:
• an ignition mechanism for generating a heat source;
• an actuating means for activating the ignition mechanism;
• a metallic shield positioned adjacent to the ignition mechanism and at a distance to the ignition mechanism such that the metallic shield is heated by the heat source when the handheld lighter is operated;
• and
• a housing comprising the ignition mechanism, the actuating means and the metallic shield;
• and
• wherein the thermochromic coating comprises:
• (a) an electron-donative organic compound (component (a)),
• (b) an electron-accepting compound (component (b)), and
• (c) a reaction medium for enabling a reversible electron transfer reaction between the components (a) and (b) above the melting or softening point of the reaction medium (component (c));
• and
• wherein the thermochromic coating is configured to reversibly change color in response to an increase of the temperature of the metallic shield to a first temperature of about 60° C. or above and to reversibly change color in response to a decrease of the temperature of the metallic shield to a second temperature which is about 0 to about 20° C. below the first temperature.