Ultraviolet Light Stable Color-Changing Systems

Abstract

Disclosed herein are embodiments of (i) a novel stabilizer including a stable nitroxide free radical which can function as a light-stabilizer and/or a heat-stabilizer, and (ii) compositions including the stable nitroxide free radical.

Claims

1. A light-stable composition comprising: a color-changing system comprising: a color-changing compound; a solvent; and a stabilizer which enhances the light-stability of said color-changing compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

2. The composition of claim 1, wherein said stable nitroxide free radical enhances lightfastness of said color-changing compound.

3. The composition of claim 1, wherein said stable nitroxide free radical interacts with free radicals generated by exposure to light.

4. The composition of claim 1, wherein an amount of said stable nitroxide free radical is not greater than about 1 percent by weight of said composition.

5. The composition of claim 1, wherein an amount of said stable nitroxide free radical is not greater than about 0.1 percent by weight of said composition.

6. The composition of claim 1, wherein an amount of said stable nitroxide free radical is not greater than about 0.01 percent by weight of said composition.

7. The composition of claim 1, wherein an amount of said stable nitroxide free radical is not greater than about 0.001 percent by weight of said composition.

8. The composition of claim 1, wherein an amount of said stable nitroxide free radical is in a range of between about 0.001 percent to about 1 percent by weight of said composition.

9. The composition of claim 1, wherein said stable nitroxide free radical is a cyclic stable nitroxide free radical which includes a ring.

10. The composition of claim 9, wherein said cyclic stable nitroxide free radical includes at least one hindering group at an alpha position relative to the nitrogen in said ring.

11. The composition of claim 9, wherein said cyclic stable nitroxide free radical belongs to a class selected from the group consisting of: imidazoline, imidazolidine, isoindoline, piperidine, pyrrolidine, pyrroline, and dioxyl nitroxide.

12. The composition of claim 9, wherein said cyclic stable nitroxide free radical is selected from the compounds of Formulas II through VIII.

13. The composition of claim 9, wherein said cyclic stable nitroxide free radical is a mono-nitroxide free radical.

14. The composition of claim 13, wherein said mono-nitroxide free radical is selected from those listed in Table 7.

15. The composition of claim 9, wherein said stable nitroxide free radical is a di-nitroxide free radical.

16. The composition of claim 15, wherein said di-nitroxide free radical is selected from those listed in Table 8.

17. The composition of claim 9, wherein said stable nitroxide free radical is a tri-nitroxide free radical.

18. The composition of claim 17, wherein said tri-nitroxide free radical is selected from those listed in Table 9.

19. The composition of claim 9, wherein said stable nitroxide free radical is a tetra-nitroxide free radical.

20. The composition of claim 19, wherein said tetra-nitroxide free radical is selected from those listed in Table 10.

21. The composition of claim 9, wherein said stable nitroxide free radical is incorporated into a polymer.

22. The composition of claim 21, wherein said stable nitroxide free radical incorporated into said polymer is selected from those listed in Table 11.

23. The composition of claim 9, wherein said stable nitroxide free radical is bonded to another molecule.

24. The composition of claim 23, wherein said stable nitroxide free radical bonded to another molecule is selected from those listed in Table 12.

25. The composition of claim 1, wherein said color-changing system is encapsulated within a microcapsule to provide a microencapsulated color-changing system.

26. The composition of claim 25, wherein said microcapsule has a diameter of less than about 5 microns.

27. The composition of claim 25, wherein said microcapsule has a diameter in a range of between about 300 nanometers to about 5 microns.

28. The composition of claim 1, wherein said color-changing compound irreversibly changes color.

29. The composition of claim 1, wherein said color-changing compound reversibly changes color.

30. The composition of claim 1, wherein said color-changing compound comprises a leuco dye.

31. The composition of claim 1, wherein said color-changing compound comprises a photochromic compound.

32. The composition of claim 1, wherein said color-changing compound comprises a thermochromic compound.

33. The composition of claim 32, wherein said thermochromic compound is an electron-donating compound.

34. The composition of claim 33, wherein said color-changing system further comprises a color developer.

35. The composition of claim 34, wherein said color developer is an electron acceptor.

36. The composition of claim 35, wherein said color developer is an acid.

37. The composition of claim 1, wherein said solvent comprises a hydrophobic phase change material.

38. The composition of claim 37, wherein said stable nitroxide free radical is soluble in said hydrophobic phase change material.

39. The composition of claim 1, wherein said solvent comprises a hydrophilic phase change material.

40. The composition of claim 39, wherein said stable nitroxide free radical is soluble in said hydrophilic phase change material.

41. The composition of claim 1, further comprising an additional color-changing compound.

42. The composition of claim 1, further comprising a colorant which does not change color.

43. The composition of claim 1, further comprising an ultraviolet light absorber.

44. The composition of claim 43, wherein said ultraviolet light absorber is selected from the group consisting of: benzophenone-based ultraviolet light absorbers, salicyclic acid-based ultraviolet light absorbers, cyano acrylate-based ultraviolet light absorbers, benzotriazole-based ultraviolet light absorbers, triazine-based ultraviolet light absorbers, and oxalic acid anilide-based ultraviolet light absorbers.

45. The composition of claim 1, further comprising an oxidative inhibitor.

46. The composition of claim 45, wherein said oxidative inhibitor is selected from the group consisting of: hindered amine-based oxidative inhibitors, phenol-based oxidative inhibitors, sulfur-based oxidative inhibitors, and phosphoric acid-based oxidative inhibitors.

47. The composition of claim 1, further comprising a quenching agent.

48. The composition of claim 47, wherein said quenching agent is selected from the group consisting of: singlet oxidative quenching agents, superoxide anion quenching agents, and ozone quenching agents.

49. The composition of claim 1, wherein said color-changing system is incorporated into a coating.

50. The composition of claim 49, wherein said color-changing system is incorporated into a metal coating.

51. The composition of claim 49, wherein upon application to a substrate, said coating forms a cured film which has a thickness in a range of between about 3 microns to about 10 microns.

52. The composition of claim 49, wherein upon application to a substrate, said coating forms a cured film which has a thickness in a range of between about 3 microns to about 5 microns.

53. The composition of claim 49, wherein said coating comprises an ink.

54. The composition of claim 53, wherein said ink is selected from the group consisting of: metal decoration inks, offset inks, lithographic inks, flexographic inks, gravure inks, and screen inks.

55. The composition of claim 53, wherein upon application to a substrate, said ink forms a cured film which has a thickness in a range of between about 3 microns to about 10 microns.

56. The composition of claim 53, wherein upon application to a substrate, said ink forms a cured film which has a thickness in a range of between about 3 microns to about 5 microns.

57. The composition of claim 1, wherein said stable nitroxide free radical comprises a cyclic stable nitroxide free radical which includes a ring.

58. The composition of claim 1, wherein said stable nitroxide free radical comprises the following formula: ##STR00049## wherein: R.sub.1 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; R.sub.2 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.3 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.4 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; and R.sub.5 and R.sub.6 are each independently alkyl, or together form a ring.

59. The composition of claim 58, wherein at least one of: R.sub.1 and R.sub.2 together form a ring; R.sub.3 and R.sub.4 together form a ring; R.sub.1 and R.sub.3 together form a ring; R.sub.2 and R.sub.4 together form a ring; or R.sub.5 and R.sub.6 together form a ring.

60. The composition of claim 59, wherein: R.sub.5 and R.sub.6 together form a ring; and said ring formed from R.sub.5 and R.sub.6 is a heterocyclic ring.

61. The composition of claim 60, wherein the nitrogen of said stable nitroxide free radical is included in said heterocyclic ring formed from R.sub.5 and R.sub.6.

62. The composition of claim 1, wherein said stable nitroxide free radical comprises the following formula: ##STR00050## wherein: R.sub.1 and R.sub.3 are each independently alkyl, or together form a ring; R.sub.2 and R.sub.4 are each independently alkyl, or together form a ring; X is independently selected from alkyl, ester, ether, amine, carbamate, amide, urea, sulfate, or thioether; R.sub.7 is selected from aliphatic, aromatic, or star-shaped amino; and a is between 1 and 4.

63. The composition of claim 1, wherein said stable nitroxide free radical comprises the following formula: ##STR00051## wherein: R.sub.1 and R.sub.3 are each independently alkyl, or together form a ring; R.sub.2 and R.sub.4 are each independently alkyl, or together form a ring; R.sub.7 is selected from aliphatic, aromatic, or star-shaped amino; and b is between 1 and 4.

64. The composition of claim 1, wherein said stable nitroxide free radical comprises the following formula: ##STR00052## wherein: R.sub.1 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; R.sub.2 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.3 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.4 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; X is independently selected from alkyl, ester, ether, amine, carbamate, amide, urea, sulfate, or thioether; G and Y are each independently a repeating unit of a polymer backbone; and n and m are each independently between 1 and 500.

65. The composition of claim 1, wherein: said light-stable composition comprises an ultraviolet light-stable composition; and said stabilizer enhances the ultraviolet light-stability of said color-changing compound.

66. The composition of claim 1 or 65, wherein said stabilizer consists essentially of said stable nitroxide free radical.

67. The composition of claim 1 or 65, wherein said stabilizer consists of said stable nitroxide free radical.

68. A light-stable composition comprising: a light-degradable compound; and a stabilizer which enhances the light-stability of said light-degradable compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

69. The composition of claim 68, wherein: said light-stable composition comprises an ultraviolet light-stable composition; said light-degradable compound comprises an ultraviolet light-degradable compound; and said stabilizer enhances the ultraviolet light-stability of said ultraviolet light-degradable compound.

70. A heat-stable composition comprising: a heat-degradable compound; and a stabilizer which enhances the heat-stability of said heat-degradable compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

71. A light-stable and heat-stable composition comprising: a light-degradable and heat-degradable compound; and a stabilizer which enhances the light-stability and heat-stability of said light-degradable and heat-degradable compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

72. The composition of claim 68, 70, or 71, wherein said stable nitroxide free radical comprises a cyclic stable nitroxide free radical which includes a ring.

73. The composition of claim 68, 70, or 71, wherein said stable nitroxide free radical comprises the following formula: ##STR00053## wherein: R.sub.1 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; R.sub.2 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.3 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.4 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; and R.sub.5 and R.sub.6 are each independently alkyl, or together form a ring.

74. A stabilizer comprising a stable nitroxide free radical.

75. The stabilizer of claim 74, wherein said stable nitroxide free radical comprises a cyclic stable nitroxide free radical which includes a ring.

76. The stabilizer of claim 74, wherein said stable nitroxide free radical comprises the following formula: ##STR00054## wherein: R.sub.1 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; R.sub.2 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.3 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.4 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; and R.sub.5 and R.sub.6 are each independently alkyl, or together form a ring.

77. A method of making a light-stable composition, comprising: making a color-changing system by combining: a color-changing compound; a solvent; and a stabilizer which enhances the light-stability of said color-changing compound; wherein said stabilizer is incorporated into said color-changing system as a stable nitroxide free radical.

78. A method of making an ultraviolet light-stable composition, comprising: making a color-changing system by combining: a color-changing compound; a solvent; and a stabilizer which enhances the ultraviolet light-stability of said color-changing compound; wherein said stabilizer is incorporated into said color-changing system as a stable nitroxide free radical.

79. A method of making a light-stable composition, comprising: combining a light-degradable compound and a stabilizer which enhances the light-stability of said light-degradable compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

80. A method of making an ultraviolet light-stable composition, comprising: combining an ultraviolet light-degradable compound and a stabilizer which enhances the ultraviolet light-stability of said ultraviolet light-degradable compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

81. A method of making a heat-stable composition, comprising: combining a heat-degradable compound and a stabilizer which enhances the heat-stability of said heat-degradable compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

82. A method of making a light-stable and heat-stable composition, comprising: combining a light-degradable and heat-degradable compound and a stabilizer which enhances the light-stability and heat-stability of said light-degradable and heat-degradable compound; wherein said stabilizer is incorporated into said composition as a stable nitroxide free radical.

83. The method of claim 77, 78, 79, 80, 81, or 82, wherein said stable nitroxide free radical comprises a cyclic stable nitroxide free radical which includes a ring.

84. The method of claim 77, 78, 79, 80, 81, or 82, wherein said stable nitroxide free radical comprises the following formula: ##STR00055## wherein: R.sub.1 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; R.sub.2 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.3 is independently alkyl, or forms a ring together with R.sub.1 or R.sub.4; R.sub.4 is independently alkyl, or forms a ring together with R.sub.2 or R.sub.3; and R.sub.5 and R.sub.6 are each independently alkyl, or together form a ring.

Description

EXAMPLE 1

[0143] As but one illustrative example shown in Table 1, in a particular embodiment of the inventive light-stable and/or heat-stable composition formulated as a thermochromic ink, incorporation of the stable nitroxide free radical (SNFR) represented by Formula XI at about 0.1% to about 5% by weight of the color-changing system resulted in a blue color-changing compound, 3,3-bis(p-dimethyl-aminophenyl)-6-dimethylaminophthalide (CAS No: 1552-42-7), exhibiting about 5 hours of lightfastness, as measured in a Q-SUN Xe-1 xenon test chamber (model Q-SUN Xe-1-B/S) using an irradiance level of 0.84 W/m.sup.2 at 420 nm with the chamber temperature at 60° Celsius. In contrast, under equivalent testing conditions, an ink including 10% TINUVIN® 400 (CAS No: 153519-44-9), which is a mixture of 2-[4-[2-Hydroxy-3-tridecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-[2-hydroxy-3-didecyloxypropyl]oxy]-2-hydroxyphenyl]-4,6-bi s(2,4-dimethylphenyl)-1,3,5-triazine, resulted in the blue color-changing compound exhibiting only about 2 hours of lightfastness. Correspondingly, at only a fraction of the amount, the instant stable nitroxide free radical (SNFR) provided a significant enhancement in lightfastness of the blue color-changing compound relative to TINUVIN® 400, which should be classified as a difference in kind, rather than one of degree. Of note, without either the instant stable nitroxide free radical (SNFR) or TINUVIN® 400, the blue color-changing compound exhibited only about 1 hour of lightfastness under equivalent testing conditions.

TABLE-US-00007 TABLE 1 Color- % Stabilizer % changing in Color- Lightfastness Compound changing Enhancement CAS Stabilizer System Lightfastness by SNFR 1552-42-7 SNFR 0.1%-5% 5 hours — 1552-42-7 TINUVIN ® 400  10% 2 hours 150% 1552-42-7 — — 1 hour 400%

EXAMPLE 2

[0144] As but a second illustrative example shown in Table 2, in a particular embodiment of the inventive light-stable and/or heat-stable composition formulated as a thermochromic ink, incorporation of the stable nitroxide free radical (SNFR) represented by Formula XI at about 0.1% to about 5% by weight of the color-changing system resulted in a blue color-changing compound, 3,3-bis(p-dimethyl-aminophenyl)-6-dimethylaminophthalide (CAS No: 1552-42-7), exhibiting about 5 hours of lightfastness, as measured in a Q-SUN Xe-1 xenon test chamber (model Q-SUN Xe-1-B/S) using an irradiance level of 0.84 W/m.sup.2 at 420 nm with the chamber temperature at 60° Celsius. In contrast, under equivalent testing conditions, an ink including 1.24% TINUVIN® 123 (CAS No: 129757-67-1), which is bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, resulted in the blue color-changing compound exhibiting only about 2 hours of lightfastness. Correspondingly, at only a fraction of the amount, the instant stable nitroxide free radical provided a significant enhancement in lightfastness of the blue color-changing compound relative to TINUVIN® 123, which should be classified as a difference in kind, rather than one of degree. Of note, without either the instant stable nitroxide free radical or TINUVIN® 123, the blue color-changing compound exhibited only about 1 hour of lightfastness under equivalent testing conditions.

TABLE-US-00008 TABLE 2 Color- % Stabilizer % changing in Color- Lightfastness Compound changing Enhancement CAS Stabilizer System Lightfastness by SNFR 1552-42-7 SNFR  0.1%-5% 5 hours — 1552-42-7 TINUVIN ® 123 1.24% 2 hours 150% 1552-42-7 — — 1 hour 400%

EXAMPLE 3

[0145] As but a third illustrative example shown in Table 3, in a particular embodiment of the inventive light-stable and/or heat-stable composition formulated as a thermochromic ink, incorporation of the stable nitroxide free radical (SNFR) represented by Formula XI at about 0.1% to about 5% by weight of the color-changing system resulted in a blue color-changing compound, 7-[4-(diethylamino)-2-ethoxyphenyl]-7-(1-ethyl-2-methyl-1H-indol-3-yl)furo[3,4-b]pyridine-5(7H)-one (CAS No: 69898-40-4), exhibiting about 9 hours of lightfastness, as measured in a Q-SUN Xe-1 xenon test chamber (model Q-SUN Xe-1-B/S) using an irradiance level of 0.84 W/m.sup.2 at 420 nm with the chamber temperature at 60° Celsius. In contrast, under equivalent testing conditions, an ink including 1.24% TINUVIN® 123 resulted in the blue color-changing compound exhibiting only about 6 hours of lightfastness. Correspondingly, at only a fraction of the amount, the instant stable nitroxide free radical provided a significant enhancement in lightfastness of the blue color-changing compound relative to TINUVIN® 123, which should be classified as a difference in kind, rather than one of degree. Of note, without either the instant stable nitroxide free radical or TINUVIN® 123, the blue color-changing compound exhibited only about 3 hours of lightfastness under equivalent testing conditions.

TABLE-US-00009 TABLE 3 Color- % Stabilizer % changing in Color- Lightfastness Compound changing Light- Enhancement CAS Stabilizer System fastness by SNFR 69898-40-4 SNFR  0.1%-5% 9 hours — 69898-40-4 TINUVIN ® 123 1.24% 6 hours  50% 69898-40-4 — — 3 hours 200%

EXAMPLE 4

[0146] As but a fourth illustrative example shown in Table 4, in a particular embodiment of the inventive light-stable and/or heat-stable composition formulated as a thermochromic ink, incorporation of the stable nitroxide free radical (SNFR) represented by Formula XI at about 0.1% to about 5% by weight of the color-changing system resulted in an aqua color-changing compound, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide (CAS No: 132467-74-4), exhibiting about 11 hours of lightfastness, as measured in a Q-SUN Xe-1 xenon test chamber (model Q-SUN Xe-1-B/S) using an irradiance level of 0.84 W/m.sup.2 at 420 nm with the chamber temperature at 60° Celsius. In contrast, under equivalent testing conditions, an ink including 1.24% TINUVIN® 123 resulted in the aqua color-changing compound exhibiting only about 8 hours of lightfastness. Correspondingly, at only a fraction of the amount, the instant stable nitroxide free radical provided a significant enhancement in lightfastness of the aqua color-changing compound relative to TINUVIN® 123, which should be classified as a difference in kind, rather than one of degree. Of note, without either the instant stable nitroxide free radical or TINUVIN® 123, the aqua color-changing compound exhibited only about 4 hours of lightfastness under equivalent testing conditions.

TABLE-US-00010 TABLE 4 Color- % Stabilizer % changing in Color- Lightfastness Compound changing Light- Enhancement CAS Stabilizer System fastness by SNFR 132467-74-4 SNFR  0.1%-5% 11 hours — 132467-74-4 TINUVIN ® 123 1.24%  8 hours 37.5% 132467-74-4 — —  4 hours  175%

EXAMPLE 5

[0147] As but a fifth illustrative example shown in Table 5, in another particular embodiment of the inventive light-stable and/or heat-stable composition formulated as a thermochromic ink, incorporation of the stable nitroxide free radical (SNFR) represented by Formula XI at about 0.1% to about 5% by weight of the color-changing system resulted in a red color-changing compound, 3,3-bis(1-n-butyl-2-methylindole-3-yl)phthalide (CAS No: 50292-91-6), exhibiting about 5 hours of lightfastness, as measured in a Q-SUN Xe-1 xenon test chamber (model Q-SUN Xe-1-B/S) using an irradiance level of 0.84 W/m.sup.2 at 420 nm with the chamber temperature at 60° Celsius. In contrast, under equivalent testing conditions, an ink including 10% TINUVIN® 400 resulted in the red color-changing compound exhibiting only about 4 hours of lightfastness. Correspondingly, at only a fraction of the amount, the instant stable nitroxide free radical provided a significant enhancement in lightfastness of the red color-changing compound relative to TINUVIN® 400, which should be classified as a difference in kind, rather than one of degree. Of note, without either the instant stable nitroxide free radical or TINUVIN® 400, the red color-changing compound exhibited only about 3 hours of lightfastness under equivalent testing conditions.

TABLE-US-00011 TABLE 5 Color- % Stabilizer % changing in Color- Lightfastness Compound changing Light- Enhancement CAS Stabilizer System fastness by SNFR 50292-91-6 SNFR 0.1%-5% 5 hours — 50292-91-6 TINUVIN ® 400  10% 4 hours 25% 50292-91-6 — — 3 hours 67%

EXAMPLE 6

[0148] As but a sixth illustrative example shown in Table 6, in a particular embodiment of the inventive light-stable and/or heat-stable composition formulated as a thermochromic ink, incorporation of the stable nitroxide free radical (SNFR) represented by Formula XI at about 0.1% to about 5% by weight of the color-changing system resulted in a red color-changing compound, 3,3-bis(1-n-butyl-2-methylindole-3-yl)phthalide (CAS No: 50292-91-6), exhibiting about 5 hours of lightfastness, as measured in a Q-SUN Xe-1 xenon test chamber (model Q-SUN Xe-1-B/S) using an irradiance level of 0.84 W/m.sup.2 at 420 nm with the chamber temperature at 60° Celsius. In contrast, under equivalent testing conditions, an ink including 1.24% TINUVIN® 123 resulted in the red color-changing compound exhibiting only about 4 hours of lightfastness. Correspondingly, at only a fraction of the amount, the instant stable nitroxide free radical provided a significant enhancement in lightfastness of the red color-changing compound relative to TINUVIN® 123, which should be classified as a difference in kind, rather than one of degree. Of note, without either the instant stable nitroxide free radical or TINUVIN® 123, the red color-changing compound exhibited only about 3 hours of lightfastness under equivalent testing conditions.

TABLE-US-00012 TABLE 6 Color- % Stabilizer % changing in Color- Lightfastness Compound changing Light- Enhancement CAS Stabilizer System fastness by SNFR 50292-91-6 SNFR  0.1%-5% 5 hours — 50292-91-6 TINUVIN ® 123 1.24% 4 hours 25% 50292-91-6 — — 3 hours 67%

[0149] A method of making the instant light-stable and/or heat-stable composition includes combining a light-degradable and/or heat-degradable compound with a stabilizer which enhances the light-stability and/or heat-stability of the light-degradable and/or heat-degradable compound, whereby the stabilizer is incorporated into the composition as a stable nitroxide free radical.

[0150] As to particular embodiments, a method of making the instant light-stable and/or heat-stable composition includes making a color-changing system by combining a color-changing compound, a solvent, and a stabilizer which enhances the light-stability and/or heat-stability of the color-changing compound, whereby the stabilizer is incorporated into the color-changing system as a stable nitroxide free radical.

[0151] Said another way, the stable nitroxide free radical is combined with the color-changing compound and the solvent to provide the color-changing system.

[0152] As used herein, the term “combination or combining” refers to any method of putting two or more materials together. Such methods include, but are not limited to, mixing, blending, commingling, concocting, homogenizing, ultrasonic homogenizing, incorporating, intermingling, fusing, joining, shuffling, stirring, coalescing, integrating, confounding, uniting, creating a solution of two or more materials, creating a suspension of two immiscible materials, such as an emulsion, via any number of means, or the like, or combinations thereof.

[0153] The method can further include combining additional components with the instant light-stable and/or heat-stable composition as described above.

[0154] As can be easily understood from the foregoing, the basic concepts of the present invention may be embodied in a variety of ways. The invention involves numerous and varied embodiments of light-stable and/or heat-stable compositions and methods for making and using such light-stable and/or heat-stable compositions.

[0155] As such, the particular embodiments or elements of the invention disclosed by the description or shown in the FIGURES or tables accompanying this application are not intended to be limiting, but rather exemplary of the numerous and varied embodiments generically encompassed by the invention or equivalents encompassed with respect to any particular element thereof. In addition, the specific description of a single embodiment or element of the invention may not explicitly describe all embodiments or elements possible; many alternatives are implicitly disclosed by the description and FIGURES.

[0156] It should be understood that each element of an apparatus or each step of a method may be described by an apparatus term or method term. Such terms can be substituted where desired to make explicit the implicitly broad coverage to which this invention is entitled. As but one example, it should be understood that all steps of a method may be disclosed as an action, a means for taking that action, or as an element which causes that action. Similarly, each element of an apparatus may be disclosed as the physical element or the action which that physical element facilitates. As but one example, the disclosure of a “combination” should be understood to encompass disclosure of the act of “combining”—whether explicitly discussed or not—and, conversely, were there effectively disclosure of the act of “combining”, such a disclosure should be understood to encompass disclosure of a “combination” and even a “means for combining”. Such alternative terms for each element or step are to be understood to be explicitly included in the description.

[0157] In addition, as to each term used it should be understood that unless its utilization in this application is inconsistent with such interpretation, common dictionary definitions should be understood to be included in the description for each term as contained in the Random House Webster's Unabridged Dictionary, second edition, each definition hereby incorporated by reference.

[0158] All numeric values herein are assumed to be modified by the term “about”, whether or not explicitly indicated. For the purposes of the present invention, ranges may be expressed as from “about” one particular value to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value to the other particular value. The recitation of numerical ranges by endpoints includes all the numeric values subsumed within that range. A numerical range of one to five includes for example the numeric values 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, and so forth. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. When a value is expressed as an approximation by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” generally refers to a range of numeric values that one of skill in the art would consider equivalent to the recited numeric value or having the same function or result. Similarly, the antecedent “substantially” means largely, but not wholly, the same form, manner or degree and the particular element will have a range of configurations as a person of ordinary skill in the art would consider as having the same function or result. When a particular element is expressed as an approximation by use of the antecedent “substantially,” it will be understood that the particular element forms another embodiment.

[0159] Moreover, for the purposes of the present invention, the term “a” or “an” entity refers to one or more of that entity unless otherwise limited. As such, the terms “a” or “an”, “one or more” and “at least one” can be used interchangeably herein.

[0160] Thus, the applicant(s) should be understood to claim at least: i) each of the light-stable and/or heat-stable compositions herein disclosed and described, ii) the related methods disclosed and described, iii) similar, equivalent, and even implicit variations of each of these devices and methods, iv) those alternative embodiments which accomplish each of the functions shown, disclosed, or described, v) those alternative designs and methods which accomplish each of the functions shown as are implicit to accomplish that which is disclosed and described, vi) each feature, component, and step shown as separate and independent inventions, vii) the applications enhanced by the various systems or components disclosed, viii) the resulting products produced by such systems or components, ix) methods and apparatuses substantially as described hereinbefore and with reference to any of the accompanying examples, x) the various combinations and permutations of each of the previous elements disclosed.

[0161] The background section of this patent application, if any, provides a statement of the field of endeavor to which the invention pertains. This section may also incorporate or contain paraphrasing of certain United States patents, patent applications, publications, or subject matter of the claimed invention useful in relating information, problems, or concerns about the state of technology to which the invention is drawn toward. It is not intended that any United States patent, patent application, publication, statement or other information cited or incorporated herein be interpreted, construed or deemed to be admitted as prior art with respect to the invention.

[0162] The claims set forth in this specification, if any, are hereby incorporated by reference as part of this description of the invention, and the applicant expressly reserves the right to use all of or a portion of such incorporated content of such claims as additional description to support any of or all of the claims or any element or component thereof, and the applicant further expressly reserves the right to move any portion of or all of the incorporated content of such claims or any element or component thereof from the description into the claims or vice-versa as necessary to define the matter for which protection is sought by this application or by any subsequent application or continuation, division, or continuation-in-part application thereof, or to obtain any benefit of, reduction in fees pursuant to, or to comply with the patent laws, rules, or regulations of any country or treaty, and such content incorporated by reference shall survive during the entire pendency of this application including any subsequent continuation, division, or continuation-in-part application thereof or any reissue or extension thereon.

[0163] Additionally, the claims set forth in this specification, if any, are further intended to describe the metes and bounds of a limited number of the preferred embodiments of the invention and are not to be construed as the broadest embodiment of the invention or a complete listing of embodiments of the invention that may be claimed. The applicant does not waive any right to develop further claims based upon the description set forth above as a part of any continuation, division, or continuation-in-part, or similar application.