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

• US 20030205059A1
• Filed: 01/13/2003
• Published: 11/06/2003
• 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:
  US10/341,525
• Publication Number:
  US 20030205059A1
• Time in Patent Office: Days
• US Class Current: 65/60.1
• 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. The portion of the substrate may substantially not fog when the portion has an initial surface temperature and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time. The surface temperature may be less than about 0° C. and the period of time may be greater than about 6 seconds.

Claims

1. A refrigerator door comprising:

a substantially transparent substrate having an anti-fog coating on at least a portion thereof, the portion of the substrate substantially not fogging when the portion has an initial surface temperature and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, wherein the surface temperature is less than about 0°

C. and the period of time is greater than about 6 seconds.

2. The refrigerator door of claim 1, wherein the period of time is greater than about 10 seconds.

3. The refrigerator door of claim 1, wherein the period of time is greater than about 30 seconds.

4. The refrigerator door of claim 1, wherein the period of time is greater than about one minute.

5. The refrigerator door of claim 1, wherein the period of time is greater than about five minutes.

6. The refrigerator door of claim 1, wherein the period of time is greater than about fifteen minutes.

7. The refrigerator door of claim 1, wherein the surface temperature is less than about −

5°

C.

8. The refrigerator door of claim 7, wherein the period of time is greater than about ten seconds.

9. The refrigerator door of claim 7, wherein the period of time is greater than about thirty seconds.

10. The refrigerator door of claim 7, wherein the period of time is greater than about one minute.

11. The refrigerator door of claim 7, wherein the period of time is greater than about five minutes.

12. The refrigerator door of claim 1, wherein the initial surface temperature is less than about −

10°

C.

13. The refrigerator door of claim 12, wherein the period of time is greater than about ten seconds.

14. The refrigerator door of claim 12, wherein the period of time is greater than about thirty seconds.

15. The refrigerator door of claim 12, wherein the period of time is greater than about one minute.

16. The refrigerator door of claim 12, wherein the period of time is greater than about five minutes.

17. The refrigerator door of claim 1, wherein the initial surface temperature is less than about −

15°

C.

18. The refrigerator door of claim 17, wherein the period of time is greater than about ten seconds.

19. The refrigerator door of claim 17, wherein the period of time is greater than about thirty seconds.

20. The refrigerator door of claim 17, wherein the period of time is greater than about one minute.

21. The refrigerator door of claim 17, wherein the period of time is greater than about five minutes.

22. The refrigerator door of claim 1, wherein the initial surface temperature is less than about −

18°

C.

23. The refrigerator door of claim 22, wherein the period of time is greater than about 10 seconds.

24. The refrigerator door of claim 22, wherein the period of time is greater than about 30 seconds.

25. The refrigerator door of claim 22, wherein the period of time is greater than about one minute.

26. The refrigerator door of claim 22, wherein the period of time is greater than about five minutes.

27. The refrigerator door of claim 22, wherein the period of time is greater than about fifteen minutes.

28. The refrigerator door of claim 1, wherein the coating comprises a hydrophobic surface having a surface tension and a hydrophilic interior having a hydrophilicity.

29. The refrigerator door of claim 28, wherein the surface tension of the hydrophobic surface is less than about 30 dynes/cm.

30. The refrigerator door of claim 29, wherein the surface tension of the surface is less than about 20 dynes/cm.

31. The refrigerator door of claim 28, wherein the hydrophilicity is between about 20% weight gain and about 150% weight gain when the coating is immersed in water for about 96 hours at about 20 to about 25°

C.

32. The refrigerator door of claim 1, wherein the coating has a taber haze of less than about 10% at 100 cycles with 500 gram load and a CS-10F load using ASTM D 4060 testing.

33. The refrigerator door of claim 1, wherein the coating comprises a polyurethane.

34. The refrigerator door of claim 1, wherein the coating is substantially free of chain extenders.

35. The refrigerator door of claim 1, wherein the refrigerator door further comprises an additional substrate having a low-emissivity surface or low-emissivity coating thereon.

36. The refrigerator door of claim 35, wherein the low-emissivity surface or coating does not emit radiation above about 0.7 microns.

37. The refrigerator door of claim 35, wherein the low-emissivity surface or coating does not emit radiation between about 0.7 microns and about 2.7 microns.

38. The refrigerator door of claim 35, wherein the low-emissivity surface or coating has a visible transmittance of about 70% to about 90%.

39. The refrigerator door of claim 1, wherein the coating exhibits less than about 0.5% detective haze by hazemeter.

40. The refrigerator door of claim 1, wherein the life of the coating is greater than about two years.

41. The refrigerator door of claim 40, wherein the life of the coating is greater than about 5 years.

42. The refrigerator door of claim 1, wherein the coating is substantially free of surfactants.

43. A refrigerator door comprising a substantially transparent substrate having an anti-fog coating on at least a portion thereof, the coating comprising a polyurethane and having a surface tension of less than about 60 dynes/cm.

44. The refrigerator door of claim 43, wherein the surface tension is less than about 30 dynes/cm.

45. The refrigerator door of claim 43, wherein the surface tension is less than about 25 dynes/cm.

46. The refrigerator door of claim 43, wherein the surface tension is less than about 20 dynes/cm.

47. The refrigerator door of claim 43, wherein the coating has an exterior portion that is hydrophobic and an interior portion that is hydrophilic.

48. The refrigerator door of claim 47, wherein the hydrophilic portion gains between about 20% weight and about 150% weight when the coating is immersed in water for about 96 hours at about 20°

to about 25°

C.

49. The refrigerator door of claim 47, wherein the hydrophilic portion gains between about 30% weight and about 140% weight when the coating is immersed in water for about 96 hours at about 20°

to about 25°

C.

50. The refrigerator door of claim 47, wherein the hydrophilic portion is between about 35% weight and about 110% weight when the coating is immersed in water for about 96 hours at about 20°

to about 25°

C.

51. The refrigerator door of claim 43, wherein the coating has a taber haze of less than about 10% at 100 cycles with 500 gram load and a CS-10F load using ASTM D 4060 testing.

52. The refrigerator door of claim 43, wherein the coating has a taber haze of less than about 5% at 100 cycles with 500 gram load and a CS-10F load using ASTM D 4060 testing.

53. The refrigerator door of claim 43, wherein the coating has a taber haze of less than about 1% at 100 cycles with 500 gram load and a CS-10F load using ASTM D 4060 testing.

54. The refrigerator door of claim 43, wherein the coating exhibits a hardness of about 2H to about 8H using ASTM D 3363.

55. The refrigerator door of claim 54, wherein the coating exhibits a hardness of about 4H to about 6H using ASTM D 3363.

56. The refrigerator door of claim 43, wherein substantially no fog forms on the portion of the substrate having the coating thereon when the substrate has an initial surface temperature of less than about 0°

C., and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, the period of time being greater than about 3 seconds.

57. The refrigerator door of claim 56, wherein the period of time is greater than about 6 seconds.

58. The refrigerator door of claim 56, wherein the period of time is greater than about 10 seconds.

59. The refrigerator door of claim 56, wherein the period of time is greater than about 30 seconds.

60. The refrigerator door of claim 56, wherein the period of time is greater than about one minute.

61. The refrigerator door of claim 56, wherein the period of time is greater than about five minutes.

62. The refrigerator door of claim 43, wherein substantially no fog forms on the portion of the substrate having the coating thereon when the substrate has an initial surface temperature of less than about −

5°

C., and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, the period of time being greater than about 3 seconds.

63. The refrigerator door of claim 62, wherein the period of time is greater than about 6 seconds.

64. The refrigerator door of claim 62, wherein the period of time is greater than about 10 seconds.

65. The refrigerator door of claim 62, wherein the period of time is greater than about one minute.

66. The refrigerator door of claim 62, wherein the period of time is greater than about five minutes.

67. The refrigerator door of claim 43, wherein substantially no fog forms on the portion of the substrate having the coating thereon when the substrate has an initial surface temperature of less than about −

10°

C., and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, the period of time being greater than about 3 seconds.

68. The refrigerator door of claim 67, wherein the period of time is greater than about 6 seconds.

69. The refrigerator door of claim 67, wherein the period of time is greater than about 10 seconds.

70. The refrigerator door of claim 67, wherein the period of time is greater than about one minute.

71. The refrigerator door of claim 67, wherein the period of time is greater than about five minutes.

72. The refrigerator door of claim 43, wherein substantially no fog forms on the portion of the substrate having the coating thereon when the substrate has an initial surface temperature of less than about −

15°

C., and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, the period of time being greater than about 6 seconds.

73. The refrigerator door of claim 72, wherein the period of time is greater than about ten seconds.

74. The refrigerator door of claim 72, wherein the period of time is greater than about thirty seconds.

75. The refrigerator door of claim 72, wherein the period of time is greater than about one minute.

76. The refrigerator door of claim 72, wherein the period of time is greater than about five minutes.

77. The refrigerator door of claim 43, wherein substantially no fog forms on the portion of the substrate having the coating thereon when the substrate has an initial surface temperature of less than about −

18°

C., and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, the period of time being greater than about 6 seconds.

78. The refrigerator door of claim 77, wherein the period of time is greater than about 10 seconds.

79. The refrigerator door of claim 77, wherein the period of time is greater than about 30 seconds.

80. The refrigerator door of claim 77, wherein the period of time is greater than about one minute.

81. The refrigerator door of claim 77, wherein the period of time is greater than about five minutes.

82. The refrigerator door of claim 77, wherein the period of time is greater than about fifteen minutes.

83. The refrigerator door of claim 43, wherein the refrigerator door further comprises another substrate having a low-emissivity surface or a low-emissivity coating thereon.

84. The refrigerator door of claim 83, wherein the low-emissivity surface or coating does not substantially emit radiation above about 0.7 microns.

85. The refrigerator door of claim 84, wherein the low-emissivity surface or coating does not substantially emit radiation between about 0.7 and about 2.7 microns.

86. The refrigerator door of claim 83, wherein the low-emissivity surface or coating has a visible transmittance of about 70% to about 90%.

87. The refrigerator door of claim 43, wherein the substrate is transparent and the coating exhibits less than about 0.5% detectable haze by hazemeter.

88. The refrigerator door of claim 43, wherein the life of the coating is greater than about two years.

89. The refrigerator door of claim 43, wherein the life of the coating is greater than about 5 years.

90. 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,

wherein the substrate is part of a refrigerator door or is used to manufacture a refrigerator door.

91. The method of claim 90, wherein the isocyanate is a blocked isocyanate.

92. The method of claim 91, wherein the blocked isocyanate comprises at least one of hexamethylene disocyanate, toluene diisocyanate, diphenylmethane diisocyanate, bis(methylcyclohexyl) diisocyanate, oxime blocked hexamethylene diisocyanate, diethyl malonate blocked toluene diisocyanate, toluene diisocyanate blocked with 3,5 dimethyl pyrazole and combinations thereof.

93. The method of claim 91, wherein the blocked isocyanate comprises toluene diisocyanate blocked with 3,5 dimethyl pyrazole.

94. The method of claim 90, wherein the isocyanate comprises at least one of a biuret, diisophorone diisocyanate, hexamethylene disocyanate, isocyanurate of a diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, bis(methylcyclohexyl) diisocyanate, oxime blocked hexamethylene diisocyanate, diethyl malonate blocked toluene diisocyanate, toluene diisocyanate blocked with 3,5 dimethyl pyrazole and combinations thereof.

95. The method of claim 90, wherein the isocyanate includes a blocking agent component including at least one of oxime, pyrazole, phenol and combinations thereof.

96. The method of claim 90, wherein curing the mixture is performed at about 80°

C. to about 180°

C.

97. The method of claim 90, wherein curing the mixture is performed at about 125°

C. to about 135°

C.

98. The method of claim 90, wherein curing the mixture takes place for at least about 10 minutes.

99. The method of claim 90, wherein the polyol comprises at least one of polyethylene glycol, polypropylene glycol, block polymers thereof, and combinations thereof.

100. The method of claim 90, wherein the polyol has a molecular weight equal to or between about 600 and about 800.

101. The method of claim 90, wherein the polyol has a molecular weight equal to or between about 800 and about 1500.

102. The method of claim 90, wherein the polyol has a molecular weight equal to or between about 1500 to about 4600.

103. The method of claim 90, wherein the polyol has a molecular weight equal to or greater than about 4600.

104. The method of claim 90, wherein the mixture is substantially free of cross-linkers.

105. The method of claim 90, the mixture is substantially free of surfactants.

106. The method of claim 90, wherein the mixing act further comprises adding a catalyst to the mixture.

107. The method of claim 90, wherein the mixture comprises about 10 to about 85 percent to polyol and about 15 percent to about 90 percent by weight isocyanate.

108. The method of claim 107, wherein the mixture further comprises at least one of a catalyst, solvent, rheological agent, and combination thereof.

109. The method of claim 90, wherein the refrigerator door comprises an additional substrate having a low-emissivity surface or a low-emissivity coating thereon.

110. The method of claim 109, wherein the low-emissivity surface or coating does not emit radiation above about 0.7 microns.

111. The method of claim 109, wherein the low-emissivity surface or coating does not emit radiation between about 0.7 and about 2.7 microns.

112. The method of claim 109, wherein the low-emissivity surface has a visible transmittance of about 70% to about 90%.

113. The method of claim 90, wherein the coating comprises a hydrophobic surface having a surface tension and a hydrophilic interior having a hydrophilicity.

114. The method of claim 113, wherein the surface tension is less than about 30 dynes/cm.

115. The method of claim 113, wherein the hydrophilicity is between about 20% weight gain and 150% weight gain when the coating is immersed in water for about 96 hours at about 20 to 25°

C.

116. The method of claim 90, wherein the coating has a taber haze of less than about 10% at 100 cycles with 500 gram load and a CS-10F load using ASTM D 4060 testing.

117. The method of claim 90, wherein substantially no fog forms on the portion of the substrate having the coating thereon when the substrate has an initial surface temperature of less than about 0°

C., and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, the period of time being greater than about 6 seconds.

118. The method of claim 117, wherein the period of time is greater than five minutes.

119. The method of claim 90, wherein substantially no fog forms on the portion of the substrate having the coating thereon when the substrate has an initial surface temperature of less than about −

18°

C., and is then exposed to a moist air ambient with a dewpoint temperature equal to or greater than the surface temperature for a period of time, the period of time being greater than about 6 seconds.

120. The method of claim 119, wherein the period of time is greater than five minutes.