Reactivity control in substituted diacetylenic monomer shelf life monitoring systems
View Patent ↗A product shelf life monitoring system comprising an active substituted diacetylenic monomer component indicator composition is responsive to an integral of varying temperature over time to effect a solid state polymerization in the active monomer which results in a visible change in color density or the like at a rate designed to closely approximate the degradation, or shelf life, of an associated foodstuff or medicament product. The reactivity of the monomer component upon which the time-temperature integral of the indicator composition, and thus the represented shelf life, primarily depends may be readily varied by refluxing a solution of the monomer in a selected solvent for a predetermined time prior to recrystallization of the monomer for incorporation into the indicator composition.
1. The method of varying the heat-induced solid state polymerization reactivity of a distinctively crystalline structured substituted diacetylenic monomer shelf life monitoring system composition, which method comprises:
a) providing a solution of said monomer component of a, in a first state of said reactivity at a temperature below the reflux temperature of said solution,
b) heating said solution to said reflux temperature in a reflux system,
c) continuing reflux of said solution for a predetermined time period, and
d) recrystallizing the solute from said refluxed solution to thereby yield said monomer component in a second state of said reactivity while having substantially retained said crystalline structure.
2. The method according to claim 1 wherein said reflux period extends up to about 45 minutes.
3. The method according to claim 1 wherein the solvent of said solution is selected from the group consisting of acetic acid and dimethyl formamide.
4. The method according to claim 3 wherein said reflux period extends from about one to 15 minutes.
5. The method according to claim 1 wherein said monomer component is selected from the group consisting of 2,4-hexadiyn-1,6-bis(alkylurea) compounds and co-crystallized combinations thereof.
6. The method according to claim 5 wherein said monomer component is selected from the group consisting of ethyl-, propyl-, and octyl-substituted 2,4-hexadiyn-1,6-bis(alkylurea) compounds and co-crystallized combinations thereof.
7. A product shelf life monitoring system composition comprising an active substituted diacetylenic monomer component derived by recrystallization from a refluxed solution of said component according to the method of claim 1 .
8. A composition according to claim 7 wherein the monomer component of said refluxed solution is selected from the group consisting of 2,4-hexadiyn-1,6-bis(alkylurea) compounds and co-crystallized combinations thereof.
9. A composition according to claim 8 wherein the monomer component of said refluxed solution is selected from the group consisting of ethyl-, propyl-, and octyl-substituted 2,4-hexadiyn-1,6-bis(alkylurea) compounds and co-crystallized combinations thereof.
10. A composition according to claim 7 wherein the solvent of said solution is selected from the group consisting of acetic acid and dimethyl formamide.
11. A composition according to claim 10 wherein the period of reflux of said component solution extends from about one to 15 minutes.
12. A product shelf life monitoring system comprising a substrate surface bearing an active indicator composition responsive in a visible change under incident thermal energy to which an associated product is susceptible, said indicator composition comprising an active substituted diacetylenic monomer component derived by recrystallization from a refluxed solution of said component according to the method of claim 1 .
13. A system according to claim 12 wherein said associated product is a foodstuff.
14. A system according to claim 12 wherein said associated product is a medicament.
15. A system according to claim 12 wherein the monomer component of said refluxed solution is selected from the group consisting of 2,4-hexadiyn-1,6-bis(alkylurea) compounds and co-crystallized combinations thereof.
16. A system according to claim 12 wherein the monomer component of said refluxed solution is selected from the group consisting of ethyl-, propyl-, and octyl-substituted 2,4-hexadiyn-1,6-bis(alkylurea) compounds and co-crystallized combinations thereof.
17. A system according to claim 16 wherein the solvent of said solution is selected from the group consisting of acetic acid and dimethyl formamide.
18. A system according to claim 17 wherein the period of reflux of said component solution extends from about one to 15 minutes.