Merchandisers having anti-fog coatings and methods for making the same

• US 20050202178A1
• Filed: 11/05/2004
• Published: 09/15/2005
• Est. Priority Date: 05/02/2002
• Status: Abandoned Application

• Current Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Original Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Inventors: Madireddi, Sesha C., Roche, John M., Raglin, Benjamin W., Bernheim, Edward A.
• Application Number:
  US10/982,396
• Publication Number:
  US 20050202178A1
• Time in Patent Office: Days
• US Class Current: 427/385.500
• CPC Class Codes: A47F 3/0434 Glass or transparent panels
• CPC Class Codes: C03C 17/322 Polyurethanes or polyisocyanates
• CPC Class Codes: C08G 18/283 Compounds containing ether groups, e.g. oxyalkylated monohydroxy compounds
• CPC Class Codes: C08G 18/4277 Caprolactone and/or substituted caprolactone
• CPC Class Codes: C08G 18/4833 Polyethers containing oxyethylene units
• CPC Class Codes: C08G 18/8074 Lactams
• CPC Class Codes: C08G 18/8093 Compounds containing active methylene groups
• CPC Class Codes: C08G 2290/00 Compositions for creating anti-fogging
• CPC Class Codes: C09D 175/04 Polyurethanes

Abstract

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.

Claims

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/cm² 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/cm² 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.