Thermal Sensitive Material
An impact-resistant thermal sensitive material comprising at least one indicator dispersed throughout a heat-sensitive matrix material is provided. An article comprising the impact-resistant thermal sensitive material undergoes a permanent color change when exposed to a pre-determined temperature.
1 . A thermal sensitive material comprising at least one indicator dispersed throughout a heat-sensitive matrix material and wherein the thermal sensitive material is impact-resistant.
2 . A thermal sensitive material according to claim 1 , wherein each indicator is different.
3 . A thermal sensitive material according to claim 1 , wherein the indicator is a dye.
4 . A thermal sensitive material according to claim 3 , wherein the dye is a reactive dye.
5 . A thermal sensitive material according to claim 4 , wherein the reactive dye permanently changes color when exposed to a specific environment.
6 . A thermal sensitive material according to claim 5 , wherein the specific environment is selected from the group consisting of: a chemical environment, heat, air, visible light, ultraviolet light, black light, ultraviolet radiation, infra-red radiation, microwave radiation, x-ray, water, and acoustic radiation
7 . A thermal sensitive material according to claim 4 , wherein the specific environment is a chemical environment comprising at least one activator.
8 . A thermal sensitive material according to claim 7 , wherein the reactive dye is an electron donor and the activator is an electron acceptor.
9 . A thermal sensitive material according to claim 4 , wherein the reactive dye is selected from the group consisting of: a fluorescent dye; a leuco dye; a pH sensitive dye;
and a metal oxide pigment.
10 . A thermal sensitive material according to claim 9 , wherein the pH sensitive dye is selected from the group consisting of: quinine, fluorescein, calcein, umbelliferone, stilbene derivatives, an optical brightener, and a fluorescent brightener.
11 . A thermal sensitive material according to claim 7 , wherein the activator is either an acid having a pKa less than that of the reactive dye or a Lewis acid.
12 . A thermal sensitive material according to claim 1 , wherein the indicator is at least one activator and wherein the thermal sensitive material is incorporated into a chemical compound having at least one dye.
13 . A thermal sensitive material according to claim 1 , wherein the heat-sensitive matrix material is either a natural polymer or a synthetic polymer.
14 . A thermal sensitive material according to claim 13 , wherein the heat-sensitive matrix material is a wax.
15 . A thermal sensitive material according to claim 13 , wherein the synthetic polymer is selected from the group consisting of: polyethylene; polypropylene; cellulose acetate; polyester; polystyrene; polyamide; polyimide; polycarbonate; polyolefin; fluoropolymer; and polyvinyl chloride.
16 . A thermal sensitive material according to claim 1 , wherein the heat-sensitive matrix material comprises a polymer blend having a plurality of thermal melting states.
17 . A thermal sensitive material according to claim 1 , wherein the heat-sensitive matrix changes physical state at temperatures ranging from about 100° C. to about 600° C.
18 . A thermal sensitive material according to claim 17 , wherein the heat-sensitive matrix material comprises a polymer having a melting point ranging from about 100° C. to about 450° C.
19 . A thermal sensitive material according to claim 1 , wherein the thermal sensitive material comprises at least one dye material dispersed throughout a first heat-sensitive matrix material forming a core and wherein the core is surrounded by an activator dispersed throughout a second heat-sensitive matrix material.
20 . A thermal sensitive material according to claim 19 , wherein the first heat-sensitive matrix material is different from the second heat-sensitive matrix material.
21 . A thermal sensitive material according to claim 19 , wherein the first heat-sensitive matrix material is the same as the second heat-sensitive matrix material.
22 . An article prepared from the thermal sensitive material according to claim 1 , wherein the article is selected from the group consisting of: a coating; a film; a paint; a decal; an applique; and a shaped article.
23 . A thermal sensitive material according to claim 22 , wherein the shaped article is selected from the group consisting of: a polymeric container; a circuit board; and an electronic device.
24 . A method for detecting thermal exposure of an article, the method comprising the steps of:
a) providing an article prepared from a thermal sensitive material comprising at least one indicator dispersed throughout a heat-sensitive matrix material and wherein the thermal sensitive material is impact-resistant; and
b) examining the article for a color change.