Merchandisers having anti-fog coatings and methods for making the same
A variety of refrigerators and merchandisers having glass or plastic substrates that are substantially fog-resistant are provided. For example, refrigerator doors having a substantially transparent substrate including an anti-fog coating on at least a portion thereof are provided. Many of the coatings exhibit color stable properties.
1 . A method of manufacturing a refrigerator door having a substantially transparent substrate, the method comprising the acts of:
mixing an isocyanate with a polyol to form a mixture;
applying the mixture to at least a portion of the substantially transparent substrate; and
curing the mixture to form a coating, the coating showing a change in L* of less than about 10.0, a change in a* of less than about 1.2, and a change in b* of less than about 6.0, when the coating is exposed to fluorescent light having a radiant intensity of 0.05 mw/cm 2 over a period of greater than 5 days, wherein, using CIELAB values, L* measures the psychometric lightness of a coating, an L* value of 100 indicating clear and a value of 0 indicating black, a* measures the color of the coating as referenced against a red(+) and green(−) axis, and b* measures the color of the coating as referenced against a yellow(+) and blue(−) axis,
wherein the substrate is part of a refrigerator door or is used to manufacture a refrigerator door.
2 . The method of claim 1 , wherein the isocyanate comprises at least one of ε-caprolactam blocked toluene diisocyanate, 3,5-dimethylpyrazole blocked toluene diisocyanate, 3,5-dimethylpyrazole blocked IPDI, 3,5-dimethylpyrazole blocked IPDI trimer, 3,5-dimethylpyrazole blocked hexamethylene diisocyanate biuret, diethyl malonate blocked hexamethylene diisocyanate biuret, ε-caprolactam blocked hexamethylene diisocyanate trimer, 3,5-dimethylpyrazole blocked hexamethylene diisocyanate trimer, methylethylketoxime blocked hexamethylene diisocyanate trimer, 3,5-dimethylpyrazole and diethyl malonate blocked IPDI trimer, 3,5-dimethylpyrazole and diethyl malonate blocked hexamethylene diisocyanate biuret, 3,5-dimethylpyrazole, diethyl malonate blocked hexamethylene diisocyanate trimer and a combination thereof.
3 . The method of claim 1 , wherein the isocyanate comprises 3,5-dimethylpyrazole blocked hexamethylene diisocyanate biuret.
4 . The method of claim 1 , wherein the polyol comprises one or more tetrahydroxy functional copolymers of ethylene oxide and propylene oxide.
5 . The method of claim 1 , wherein the mixture comprises about 51 to 66% by weight hexamethylene diisocyanate and about 20 to 37% by weight of polyol.
6 . The method of claim 1 , wherein the isocyanate comprises 3,5-dimethylpyrazole blocked hexamethylene diisocyanate and the polyol comprises tetrahydroxy functional copolymers of ethylene oxide and propylene oxide.
7 . The method of claim 1 , wherein the change in L* is less than about 0.05, the change in a* is less than about 0.15, and the change in b* is less than about 0.25.
8 . The method of claim 7 , wherein the period is greater than 30 days.
9 . The method of claim 1 , wherein the period is greater than 30 days.
10 . A refrigerator door comprising a substantially transparent substrate having an anti-fog coating on at least a portion thereof, the coating showing a change in L* of less than about 10.0, a change in a* of less than about 1.2, and a change in b* of less than about 6.0, when the coating is exposed to fluorescent light having a radiant intensity of 0.05 mw/cm 2 over a period of greater than 5 days, wherein, using CIELAB values, L* measures the psychometric lightness of a coating, an L* value of 100 indicating clear and a value of 0 indicating black, a* measures the color of the coating as referenced against a red(+) and green(−) axis, and b* measures the color of the coating as referenced against a yellow(+) and blue(−) axis.
11 . The refrigerator door of claim 10 , wherein the change in L* is less than about 5.0, the change in a* is less than about 0.6, and the change in b* is less than about 3.0.
12 . The refrigerator door of claim 10 , wherein the change in L* is less than about 2.5, the change in a* is less than about 0.3, and the change in b* is less than about 1.5.
13 . The refrigerator door of claim 10 , wherein the change in L* is less than about 1.25, the change in a* is less than about 0.15, and the change in b* is less than about 0.75.
14 . The refrigerator door of claim 10 , wherein the change in L* is less than about 0.65, the change in a* is less than about 0.15, and the change in b* is less than about 0.5.
15 . The refrigerator door of claim 10 , wherein the change in L* is less than about 0.1, the change in a* is less than about 0.15, and the change in b* is less than about 0.25.
16 . The refrigerator door of claim 10 , wherein the change in L* is less than about 0.05, the change in a* is less than about 0.15, and the change in b* is less than about 0.25.
17 . The refrigerator door of claim 10 , wherein the period is greater than 10 days.
18 . The refrigerator door of claim 10 , wherein the period is greater than 15 days.
19 . The refrigerator door of claim 10 , wherein the period is greater than 20 days.
20 . The refrigerator door of claim 10 , wherein the period is greater than 25 days.
21 . The refrigerator door of claim 10 , wherein the period is greater than 30 days.
22 . The refrigerator door of claim 16 , wherein the period is greater than 10 days.
23 . The refrigerator door of claim 16 , wherein the period is greater than 15 days.
24 . The refrigerator door of claim 16 , wherein the period is greater than 20 days.
25 . The refrigerator door of claim 16 , wherein the period is greater than 25 days.
26 . The refrigerator door of claim 16 , wherein the period is greater than 30 days.
27 . The refrigerator door of claim 16 , wherein the coating is formed by curing a mixture comprising hexamethylene diisocyanate and one or more tetrahydroxy functional copolymers of ethylene oxide and propylene oxide.
28 . The refrigerator door of claim 27 , wherein the hexamethylene diisocyanate comprises a 3,5-dimethylpyrazole blocked hexamethylene diisocyanate.