Polymer, polymer microfiber, polymer nanofiber and applications including filter structures

• US 7,270,693 B2
• Filed: 01/16/2006
• Issued: 09/18/2007
• Est. Priority Date: 09/05/2000
• Status: Expired due to Term

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Chung, Hoo Y., Gogins, Mark A., Weik, Thomas M., Hall, John R.B., Crofoot, Douglas G.
• Primary Examiner(s): Greene; Jason M.
• Application Number:
  US11/331,555
• Publication Number:
  US 20060117730A1
• Time in Patent Office: 610 Days
• Field of Search: 553/853, 554/82, 554/86, 554/87, 554/95, 554/98, 555/02, 555/27, 555/28, 442/36, 442/340, 442/351, 428/357, 428/903, 428/339
• US Class Current: 55/528
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 46/0001 Making filtering elements
• CPC Class Codes: B01D 46/521 using folded, pleated material
• CPC Class Codes: B01D 46/546 using nano- or microfibres
• CPC Class Codes: D01D 5/003 the material being a polymer solution or dispersion D01D5/0053 takes precedence
• CPC Class Codes: D01F 6/80 from copolyamides
• CPC Class Codes: D01F 6/90 of polyamides
• CPC Class Codes: Y10S 428/903 Microfiber, less than 100 micron diameter
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 442/16 Two or more nonwoven layers
• CPC Class Codes: Y10T 442/614 Strand or fiber material specified as having microdimensions [i.e., microfiber]
• CPC Class Codes: Y10T 442/626 Microfiber is synthetic polymer

Abstract

Disclosed are improved polymer materials. Also disclosed are fine fiber materials that can be made from the improved polymeric materials in the form of microfiber and nanofiber structures. The microfiber and nanofiber structures can be used in a variety of useful applications including the formation of filter materials.

Claims

1. A fine fiber layer comprising a fiber comprising a condensation polymer and a resinous additive, the additive comprising an oligomer having a molecular weight of about 500 to 3000 and an aromatic character wherein the additive is miscible in the condensation polymer and the layer comprises a random distribution of the fiber, the fiber having a diameter of 0.001 to 2 microns.

2. The fine fiber layer of claim 1 wherein the fibers after exposure to air at 140°

F. and 100% humidity for 1 to 6 hours, at least 50% of the fiber remains substantially unchanged.

3. The fine fiber layer of claim 1 wherein the condensation polymer comprises a polyamide.

4. The fine fiber layer of claim 1 wherein the condensation polymer comprises a polyethylene terephthalate.

5. The fine fiber layer of claim 3 wherein the polyamide polymer comprises a nylon polymer comprising a homopolymer having repeating units derived from a cyclic lactam.

6. The fine fiber layer of claim 3 wherein the polyamide copolymer comprises a first nylon polymer combined with a second nylon polymer, the second nylon polymer differing in molecular weight or monomer composition.

7. The fine fiber layer of claim 6 wherein the second nylon polymer comprises a nylon copolymer.

8. The fine fiber layer of claim 6 wherein the polymers are treated to form a single polymeric composition as measured by a differential scanning calorimeter showing a single phase material.

9. The fine fiber layer of claim 1 wherein the additive comprises an oligomer comprising tertiary butyl phenol.

10. The fine fiber layer of claim 1 wherein the additive comprises an oligomer comprising bis-phenol A.

11. The fine fiber layer of claim 1 wherein the additive comprises an oligomer comprising dihydroxy biphenyl.

12. The fine fiber layer of claim 1 wherein the additive comprises a fluoropolymer.

13. The fine fiber layer of claim 1 wherein the condensation polymer comprises a blend of a condensation polymer and a polyamide polymer.

14. The fine fiber layer of claim 13 wherein the polyamide polymer comprises nylon.

15. The fine fiber layer of claim 1 wherein the condensation polymer comprises an aromatic polyamide.

16. The fine fiber layer of claim 1 wherein the condensation polymer comprises a polyarylate.

17. The fine fiber layer of claim 1 wherein the additive comprises an oligomer having a molecular weight of about 500 to 3000 and an aromatic character wherein the additive is miscible in the condensation polymer.

18. The fine fiber layer of claim 1 additionally comprising a substrate layer.

19. The fine fiber layer of claim 1 wherein the fine fiber diameter is about 0.001 to about 2 microns and the thickness of the layer is about 1 to 100 times the diameter of the fine fiber.

20. The fine fiber layer of claim 19 wherein the layer thickness is 1 to 8 times the diameter of the fine fiber.

21. The fine fiber layer of claim 19 wherein the layer thickness is about 1 to 5 times the diameter of the fiber.

22. The fine fiber layer of claim 1 wherein the layer thickness is about 1 to 30 microns.

23. The fine fiber layer of claim 1 wherein the layer is a bilayer of fine fiber.

24. The fine fiber layer of claim 1 wherein the layer is a multilayer of fine fiber.

25. The fine fiber layer of claim 18 wherein the substrate comprises a cellulosic substrate.

26. The fine fiber layer of claim 18 wherein the substrate comprises a mixed cellulosic and synthetic substrate.

27. The fine fiber layer of claim 18 wherein the substrate comprises a polymeric non-woven substrate.

28. A fine fiber layer comprising a fiber comprising an addition polymer and about 2 to 25 wt. % of an additive, the additive comprising a resinous material having a molecular weight of about 500 to 3000 and an aromatic character, wherein the additive is miscible in the polymer;

the layer comprising a random distribution of the fiber, the fine fiber having a diameter of 0.001 to 2 microns.

29. The fine fiber layer of claim 28 wherein the fibers after exposure to air at 140°

F. and 100% humidity for 1 to 6 hours, at least 50% of the fiber remains substantially unchanged.

30. The fine fiber layer of claim 28 wherein the additive comprises a hydrophobic coating on the fine fiber surface.

31. The fine fiber layer of claim 30 wherein the coating has a thickness of less than 100 Å

.

32. The fine fiber layer of claim 28 wherein the additive comprises an oligomer comprising tertiary butyl phenol.

33. The fine fiber layer of claim 28 wherein the additive comprises bis-phenol A.

34. The fine fiber layer of claim 28 wherein the additive comprises an oligomer comprising dihydroxy biphenyl.

35. The fine fiber layer of claim 28 wherein the diameter of the fiber is about 0.1 to about 2 micron.

36. The fine fiber layer of claim 28 wherein the diameter of the fiber is about 0.1 to about 0.5 micron.

37. The fine fiber layer of claim 28 wherein the diameter of the fiber is about 0.05 to about 0.2 micron.

38. The fine fiber layer of claim 28 additionally comprising a substrate layer.

39. The fine fiber layer of claim 28 wherein the fine fiber diameter is about 0.001 to about 2 microns and the thickness of the layer is about 1 to 100 times the diameter of the fine fiber.

40. The fine fiber layer of claim 39 wherein the layer thickness is 1 to 8 times the diameter of the fine fiber.

41. The fine fiber layer of claim 39 wherein the layer thickness is about 1 to 5 times the diameter of the fiber.

42. The fine fiber layer of claim 28 wherein the layer thickness is about 1 to 30 microns.

43. The fine fiber layer of claim 28 wherein the layer is a bilayer of fine fiber.

44. The fine fiber layer of claim 28 wherein the layer is a multilayer of fine fiber.

45. The fine fiber layer of claim 38 wherein the substrate comprises a cellulosic substrate.

46. The fine fiber layer of claim 38 wherein the substrate comprises a mixed cellulosic and synthetic substrate.

47. The fine fiber layer of claim 38 wherein the substrate comprises a polymeric non-woven substrate.

48. A fine fiber layer comprising a fiber comprising the reaction product of a condensation polymer and a crosslinking agent;

the layer comprising a random distribution of the fiber, the fiber having a diameter of 0.001 to 2 microns.

49. The fine fiber layer of claim 48 wherein the fibers after exposure to air at 140°

F. and 100% humidity for 1 to 6 hours, at least 50% of the fiber remains substantially unchanged.

50. The fine fiber layer of claim 48 wherein the condensation polymer comprises a polyester.

51. The fine fiber layer of claim 50 wherein the condensation polymer comprises a polyethylene terephthalate.

52. The fine fiber layer of claim 48 wherein the condensation polymer comprises a nylon polymer comprising a homopolymer having repeating units derived from a cyclic lactam.

53. The fine fiber layer of claim 48 wherein the condensation polymer comprises a first nylon polymer combined with a second nylon polymer, the second nylon polymer differing in molecular weight or monomer composition.

54. The fine fiber layer of claim 53 wherein the second nylon polymer comprises a nylon copolymer.

55. The fine fiber layer of claim 53 wherein the polymers are treated to form a single polymeric composition as measured by a differential scanning calorimeter showing a single phase material.

56. The fine fiber layer of claim 48 wherein the condensation polymer comprises a blend of a condensation polymer and a polyamide polymer.

57. The fine fiber layer of claim 56 wherein the polyamide polymer comprises nylon.

58. The fine fiber layer of claim 48 wherein the condensation polymer comprises an aromatic polyamide.

59. The fine fiber layer of claim 48 wherein the condensation polymer comprises a polyarylate.

60. The fine fiber layer of claim 48 wherein the crosslinking agent comprises a polymer comprising repeating units of acrylic acid, the polymer having a molecular weight of about 1000 to 5000.

61. The fine fiber layer of claim 60 wherein the crosslinking agent polymer comprises an acrylic acid copolymer having a molecular weight of 1000 to 5000.

62. The fine fiber layer of claim 48 wherein the crosslinking agent comprises a melamine formaldehyde resin.

63. The fine fiber layer of claim 48 wherein the crosslinking agent comprises an aldehyde crosslinking agent substantially free of formaldehyde.

64. The fine fiber layer of claim 48 additionally comprising a substrate layer.

65. The fine fiber layer of claim 48 wherein the fine fiber diameter is about 0.00 1 to about 2 microns and the thickness of the layer is about 1 to 100 times the diameter of the fine fiber.

66. The fine fiber layer of claim 65 wherein the layer thickness is 1 to 8 times the diameter of the fine fiber.

67. The fine fiber layer of claim 65 wherein the layer thickness is about 1 to 5 times the diameter of the fiber.

68. The fine fiber layer of claim 65 wherein the layer thickness is about 1 to 30 microns.

69. The fine fiber layer of claim 48 wherein the layer is a bilayer of fine fiber.

70. The fine fiber layer of claim 48 wherein the layer is a multilayer of fine fiber.

71. The fine fiber layer of claim 64 wherein the substrate comprises a cellulosic substrate.

72. The fine fiber layer of claim 64 wherein the substrate comprises a mixed cellulosic and synthetic substrate.

73. The fine fiber layer of claim 64 wherein the substrate comprises a polymeric non-woven substrate.

74. A fine fiber layer comprising a fiber comprising the reaction product of a crosslinking agent and an addition polymer;

the layer comprising a random distribution of the fiber, the fiber having a diameter of 0.01 to 2 microns.

75. The fine fiber layer of claim 74 wherein the fibers after exposure to air at 140°

F. and 100% humidity for 1 to 6 hours, at least 50% of the fiber remains substantially unchanged.

76. The fine fiber layer of claim 74 wherein the crosslinking agent comprises a polymer comprising repeating units of acrylic acid, the polymer having a molecular weight of about 1000 to 5000.

77. The fine fiber layer of claim 76 wherein the crosslinking agent polymer comprises an acrylic acid copolymer having a molecular weight of 1000 to 5000.

78. The fine fiber layer of claim 74 wherein the crosslinking agent comprises a melamine formaldehyde resin.

79. The fine fiber layer of claim 74 wherein the crosslinking agent comprises an aldehyde crosslinking agent substantially free of formaldehyde.

80. The fine fiber layer of claim 74 wherein the diameter of the fiber is about 0.1 to about 2 micron.

81. The fine fiber layer of claim 74 wherein the diameter of the fiber is about 0.1 to about 0.5 micron.

82. The fine fiber layer of claim 74 wherein the diameter of the fiber is about 0.05 to about 0.2 micron.

83. The fine fiber layer of claim 74 additionally comprising a substrate layer.

84. The fine fiber layer of claim 74 wherein the fine fiber diameter is about 0.001 to about 2 microns and the thickness of the layer is about 1 to 100 times the diameter of the fine fiber.

85. The fine fiber layer of claim 84 wherein the layer thickness is 1 to 8 times the diameter of the fine fiber.

86. The fine fiber layer of claim 84 wherein the layer thickness is about 1 to 5 times the diameter of the fiber.

87. The fine fiber layer of claim 74 wherein the layer thickness is about 1 to 30 microns.

88. The fine fiber layer of claim 74 wherein the layer is a bilayer of fine fiber.

89. The fine fiber layer of claim 74 wherein the layer is a multilayer of fine fiber.

90. The fine fiber layer of claim 83 wherein the substrate comprises a cellulosic substrate.

91. The fine fiber layer of claim 83 wherein the substrate comprises a mixed cellulosic and synthetic substrate.

92. The fine fiber layer of claim 83 wherein the substrate comprises a polymeric non-woven substrate.

93. A fine fiber layer comprising a fiber comprising the reaction product of a polyvinyl alcohol polymer and a crosslinking agent, the layer comprising a random distribution of the fiber, the fiber having a fiber diameter of about 0.001 to 2 micron.

94. The fine fiber layer of claim 93 wherein the fine fiber comprises a blend of two polyvinyl alcohol polymers and has a diameter of 0.01 to 0.5 micron.

95. The fine fiber layer of claim 93 wherein the fine fiber has a diameter of 0.01 to 0.2 micron.

96. The fine fiber layer of claim 93 wherein the fiber, when exposed to an air stream having a temperature of about 140°

F. and a relative humidity of about 100%, greater than about 50% of the fiber survives for more than 1-16 hours.

97. The fine fiber layer of claim 93 wherein the polyvinyl alcohol is partially hydrolyzed.

98. The fine fiber layer of claim 93 wherein the polyvinyl alcohol is fully hydrolyzed.

99. The fine fiber layer of claim 98 wherein the fine fiber comprises about 0.1 to 40 wt % of the crosslinking agent.

100. The fine fiber layer of claim 99 wherein the crosslinking agent comprises urea formaldehyde, melamine formaldehyde, phenol formaldehyde, or mixtures thereof.

101. The fine fiber layer of claim 100 wherein the crosslinking agent comprises a dialdehyde, trialdehyde, tetraaldehyde, a diacid, a urethane reactant, epoxy reactant, or mixtures thereof.

102. The fine fiber layer of claim 93 comprising a layer having a thickness of less than about 30 microns.

103. The fine fiber layer of claim 93 comprising a layer having a thickness of less than about 20 microns.

104. The fine fiber layer of claim 93 additionally comprising a substrate layer.

105. The fine fiber layer of claim 93 wherein the fine fiber diameter is about 0.001 to about 2 microns and the thickness of the layer is about 1 to 100 times the diameter of the fine fiber.

106. The fine fiber layer of claim 105 wherein the layer thickness is 1 to 8 times the diameter of the fine fiber.

107. The fine fiber layer of claim 105 wherein the layer thickness is about 1 to 5 times the diameter of the fiber.

108. The fine fiber layer of claim 93 wherein the layer thickness is about 1 to 30 microns.

109. The fine fiber layer of claim 93 wherein the layer is a bilayer of fine fiber.

110. The fine fiber layer of claim 93 wherein the layer is a multilayer of fine fiber.

111. The fine fiber layer of claim 104 wherein the substrate comprises a cellulosic substrate.

112. The fine fiber layer of claim 104 wherein the substrate comprises a mixed cellulosic and synthetic substrate.

113. The fine fiber layer of claim 104 wherein the substrate comprises a polymeric non-woven substrate.

114. A fine fiber layer comprising a fiber comprising the reaction product of a polyurethane polymer and a crosslinking agent, the layer comprising a random distribution of the fiber, the fiber having a fiber diameter of about 0.01 to 2 micron.

115. The fine fiber layer of claim 114 wherein the fine fiber comprises a blend of two polyurethane polymers and has a fiber diameter of 0.01 to 0.5 micron.

116. The fine fiber layer of claim 114 wherein the fine fiber has a diameter of 0.01 to 0.2 micron.

117. The fine fiber layer of claim 114 wherein the fiber, when exposed to an air stream having a temperature of about 140°

F. and a relative humidity of about 100%, greater than about 50% of the fiber survives for more than 1-16 hours.

118. The fine fiber layer of claim 117 wherein the fine fiber comprises about 0.1 to 40 wt % of the crosslinking agent.

119. The fine fiber layer of claim 118 wherein the crosslinking agent comprises urea formaldehyde, melamine formaldehyde, phenol formaldehyde, or mixtures thereof.

120. The fine fiber layer of claim 119 wherein the crosslinking agent comprises a dialdehyde, trialdehyde, tetraaldehyde, a diacid, a urethane reactant, epoxy reactant, or mixtures thereof.

121. The fine fiber layer of claim 114 additionally comprising a substrate layer.

122. The fine fiber layer of claim 114 wherein the fine fiber diameter is about 0.001 to about 2 microns and the thickness of the layer is about 1 to 100 times the diameter of the fine fiber.

123. The fine fiber layer of claim 122 wherein the layer thickness is 1 to 8 times the diameter of the fine fiber.

124. The fine fiber layer of claim 122 wherein the layer thickness is about 1 to 5 times the diameter of the fiber.

125. The fine fiber layer of claim 121 wherein the layer thickness is about 1 to 30 microns.

126. The fine fiber layer of claim 121 wherein the layer is a bilayer of fine fiber.

127. The fine fiber layer of claim 121 wherein the layer is a multilayer of fine fiber.