U.S. patent application number 10/833229 was filed with the patent office on 2004-10-14 for wipe material with nanofiber layer on a flexible substrate.
This patent application is currently assigned to Donaldson Company, Inc.. Invention is credited to Grafe, Timothy H., Graham, Kristine M..
Application Number | 20040203306 10/833229 |
Document ID | / |
Family ID | 32229824 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040203306 |
Kind Code |
A1 |
Grafe, Timothy H. ; et
al. |
October 14, 2004 |
Wipe material with nanofiber layer on a flexible substrate
Abstract
A flexible wipe, comprising at least one conformable woven or
non-woven layer and at least one adhered nanofiber layer, can be
used to remove a variety of particulate soils from planar, curved
or complex surfaces that are contaminated by small particulate
soil. The nanofiber layer is configured onto the flexible non-woven
in a fashion such that particulate of a broad particle size range
is trapped or incorporated by the nanofiber layer and efficiently
removed from the contaminated surface. The nanofiber layer
comprises a web of spun fibers that can incorporate and trap soil
particles for efficient soil removal.
Inventors: |
Grafe, Timothy H.; (Edina,
MN) ; Graham, Kristine M.; (Minnetonka, MN) |
Correspondence
Address: |
Merchant & Gould P.C.
P.O. Box 2903
Minneapolis
MN
55402-0903
US
|
Assignee: |
Donaldson Company, Inc.
|
Family ID: |
32229824 |
Appl. No.: |
10/833229 |
Filed: |
April 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10833229 |
Apr 26, 2004 |
|
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10295017 |
Nov 13, 2002 |
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Current U.S.
Class: |
442/189 ;
15/209.1; 442/340; 442/341; 442/351 |
Current CPC
Class: |
D04H 1/559 20130101;
Y10T 442/2508 20150401; Y10T 442/2402 20150401; Y10T 442/2139
20150401; B32B 2262/0261 20130101; Y10T 442/626 20150401; A45D
2200/1036 20130101; B32B 2432/00 20130101; C11D 17/049 20130101;
Y10T 442/3065 20150401; D04H 1/4374 20130101; Y10T 442/2049
20150401; A45D 2200/1018 20130101; A45D 34/00 20130101; Y10T
442/277 20150401; A47L 13/16 20130101; B08B 1/00 20130101; B32B
5/26 20130101; Y10T 442/615 20150401; B32B 5/08 20130101; Y10T
442/2041 20150401; Y10T 442/614 20150401; D04H 1/728 20130101 |
Class at
Publication: |
442/189 ;
442/340; 442/341; 442/351; 015/209.1 |
International
Class: |
A47L 013/17; A47L
013/16; B32B 027/02 |
Claims
We claim:
1. A wipe conformable to a surface, the wipe comprising at least a
flexible substrate and a nanofiber layer, the flexible substrate
comprising a layer having a thickness of about 0.01 to 0.2 cm, the
nanofiber layer comprising fiber having a diameter of about 0.001
to about 5 microns, a basis weight of about 0.0012 to about 3.5
grams-m.sup.-2, the layer having a pore size less than about 20
microns.
2. The wipe of claim 1 wherein the substrate comprises a woven
fabric having a thickness of about 0.02 to 0.1 cm and a nanofiber
layer having a fiber size of about 0.05 to 0.5 micron and a basis
weight of about 0.1 to 0.5 gm-m.sup.-2.
3. The wipe of claim 1 wherein the substrate comprises a cellulosic
non-woven having a thickness of about 0.02 to 0.1 cm and a
nanofiber layer having a fiber size of about 0.05 to 0.5 micron and
a basis weight of about 0.1 to 0.5 gm-m.sup.-2.
4. The wipe of claim 1 wherein the substrate comprises a blended
polymer cellulosic non-woven having a thickness of about 0.02 to
0.1 cm and a nanofiber layer having a fiber size of about 0.05 to
0.5 micron and a basis weight of about 0.1 to 0.5 gm-m.sup.-2.
5. The wipe of claim 1 wherein the nanofiber has a microporous
structure characterized by a pore size that ranges from about 10 to
500 nM.
6. The wipe of claim 1 wherein the nanofiber has a micro porous
structure characterized by a pore size that ranges from about 50 to
250 nM.
7. The wipe of claim 1 wherein the nanofiber is less than 1 micron
in diameter and the substrate comprises a non-woven fabric made
from both cellulosic and polymeric fiber materials.
8. The wipe of claim 1 wherein the wipe has a stiffness measured
according to TAPPI T 543 om-00: "Bending Resistance of Paper
(Gurley-Type Tester)" less than 300 milligrams.
9. The wipe of claim 1 wherein the wipe is combined with a liquid
cleaner material wherein the nanofiber layer in contact with soil
can incorporate the soil particulate into the nanofiber layer for
improved cleaning.
10. The wipe of claim 1 wherein the wipe is combined with a liquid
lubricant.
11. The wipe of claim 1 wherein the wipe is combined with a
tackifier.
12. The wipe of claim 1 wherein the wipe is combined with a liquid
coating composition.
13. The wipe of claim 9 wherein the liquid cleaner material
comprises an aqueous cleaner.
14. The wipe of claim 1 wherein the nanofiber comprises an addition
polymer.
15. The wipe of claim 14 wherein the addition polymer additionally
comprises an additive.
16. The wipe of claim 15 wherein the additive comprises a
hydrophobic coating on the fine fiber surface.
17. The wipe of claim 16 wherein the hydrophobic coating has a
thickness of less than 100 .ANG..
18. The wipe of claim 14 wherein the addition polymer comprises a
polyvinyl halide polymer, a polyvinylidene halide polymer or
mixtures thereof.
19. The wipe of claim 14 wherein the addition polymer comprises a
polyvinyl alcohol.
20. The wipe of claim 14 wherein the addition polymer comprises a
fluoropolymer.
21. The wipe of claim 14 wherein the addition polymer comprises a
fluoropolymer elastomer.
22. The wipe of claim 19 wherein the polyvinyl alcohol is
crosslinked with about 1 to 40 wt. % of a crosslinking agent.
23. The wipe of claim 22 wherein the crosslinking agent comprises a
polymer comprising repeating units of acrylic acid, the polymer
having a molecular weight of about 1000 to 5000.
24. The wipe of claim 22 wherein the crosslinking agent comprises a
melamine-formaldehyde resin having a molecular weight of about 1000
to 3000.
25. The wipe of claim 18 wherein the polyvinyl halide is
crosslinked.
26. The wipe of claim 1 wherein the nanofiber comprises
condensation polymer.
27. The wipe of claim 26 wherein the condensation polymer
additionally comprises an additive.
28. The wipe of claim 27 wherein the additive comprises a
hydrophobic coating on the fine fiber surface.
29. The wipe of claim 28 wherein the hydrophobic coating has a
thickness of less than 100 .ANG..
30. The wipe of claim 26 wherein the condensation polymer comprises
a polyester.
31. The wipe of claim 26 wherein the condensation polymer comprises
a nylon polymer.
32. The wipe of claim 31 wherein the nylon polymer is combined with
a second nylon polymer, the second nylon polymer differing in
molecular weight or monomer composition.
33. The wipe of claim 27 wherein the additive comprises a
fluoropolymer.
34. The wipe of claim 26 wherein the condensation polymer comprises
a polyurethane polymer.
35. The wipe of claim 26 wherein the condensation polymer comprises
an aromatic polyamide.
36. The wipe of claim 26 wherein the condensation polymer comprises
a polyarylate.
37. The wipe of claim 31 wherein the nylon copolymer comprises
repeating units derived from a cyclic lactam, a C.sub.6-10 diamine
monomer and a C.sub.6-10 diacid monomer.
38. The wipe of claim 26 wherein the nanofiber comprises about 2 to
25 wt % of an additive comprising a resinous material having a
molecular weight of about 500 to 3000 and the additive is miscible
in the polymer.
39. The wipe of claim 38 wherein the additive comprising a resinous
material having an aromatic character.
40. A wipe conformable to a surface, the wipe comprising at least a
flexible substrate having a first and a second side and a non-woven
nanofiber layer on both the first and the second side, the flexible
substrate comprising a layer having a thickness of about 0.01 to
0.2 cm, the nanofiber comprises a layer comprising fiber having a
diameter of about 0.001 to about 5 microns, a basis weight of about
0.0012 to about 3.5 grams-m.sup.-2, the layer having a pore size
less than about 20 microns.
41. The wipe of claim 40 wherein the wipe comprises a woven fabric
having a thickness of about 0.02 to 0.1 cm and a nanofiber layer
having a fiber size of about 0.05 to 0.5 micron and a basis weight
of about 0.1 to 0.5 gm-m.sup.-2.
42. The wipe of claim 40 wherein the wipe comprises a cellulosic
non-woven having a thickness of about 0.02 to 0.1 cm and a
nanofiber layer having a fiber size of about 0.05 to 0.5 micron and
a basis weight of about 0.1 to 0.5 gm-m.sup.-2.
43. The wipe of claim 40 wherein the wipe comprises a blended
polymer cellulosic non-woven having a thickness of about 0.02 to
0.1 cm and a nanofiber layer having a fiber size of about 0.05 to
0.5 micron and a basis weight of about 0.1 to 0.5 gm-m.sup.2.
44. The wipe of claim 40 wherein the nanofiber has a microporous
structure characterized by a pore size that ranges from about 10 to
500 nM.
45. The wipe of claim 40 wherein the nanofiber has a micro porous
structure characterized by a pore size that ranges from about 50 to
250 nM.
46. The wipe of claim 40 wherein the substrate comprises a
non-woven fabric made from both cellulosic and polymeric fiber
materials.
47. The wipe of claim 40 wherein the wipe has stiffness measured
according to TAPPI T 543 om-00: "Bending Resistance of Paper
(Gurley-Type Tester)" less than 300 milligrams.
48. The wipe of claim 40 wherein the wipe is combined with a liquid
cleaner material wherein the nanofiber layer in contact with soil
can incorporate the soil particulate into the nanofiber layer for
improved cleaning.
49. The wipe of claim 40 wherein the wipe is combined with a
tackifier.
50. The wipe of claim 40 wherein the wipe is combined with a liquid
lubricant.
51. The wipe of claim 40 wherein the wipe is combined with a liquid
coating composition.
52. The wipe of claim 48 wherein the liquid cleaner material
comprises an aqueous cleaner.
53. The wipe of claim 40 wherein the nanofiber comprises an
addition polymer.
54. The wipe of claim 53 wherein the addition polymer additionally
comprises an additive.
55. The wipe of claim 54 wherein the additive comprises a
hydrophobic coating on the fine fiber surface.
56. The wipe of claim 55 wherein the hydrophobic coating has a
thickness of less than 100 .ANG..
57. The wipe of claim 53 wherein the addition polymer comprises a
polyvinyl halide polymer, a polyvinylidene halide polymer or
mixtures thereof.
58. The wipe of claim 53 wherein the addition polymer comprises a
polyvinyl alcohol.
59. The wipe of claim 53 wherein the addition polymer comprises a
fluoropolymer.
60. The wipe of claim 53 wherein the addition polymer comprises a
fluoropolymer elastomer.
61. The wipe of claim 58 wherein the polyvinyl alcohol is
crosslinked with about 1 to 40 wt. % of a crosslinking agent.
62. The wipe of claim 61 wherein the crosslinking agent comprises a
polymer comprising repeating units of acrylic acid, the polymer
having a molecular weight of about 1000 to 5000.
63. The wipe of claim 61 wherein the crosslinking agent comprises a
melamine-formaldehyde resin having a molecular weight of about 1000
to 3000.
64. The wipe of claim 57 wherein the polyvinyl halide is
crosslinked.
65. The wipe of claim 40 wherein the nanofiber comprises
condensation polymer.
66. The wipe of claim 65 wherein the condensation polymer
additionally comprises an additive.
67. The wipe of claim 66 wherein the additive comprises a
hydrophobic coating on the fine fiber surface.
68. The wipe of claim 67 wherein the hydrophobic coating has a
thickness of less than 100 .ANG..
69. The wipe of claim 65 wherein the condensation polymer comprises
a polyester.
70. The wipe of claim 65 wherein the condensation polymer comprises
a nylon polymer.
71. The wipe of claim 70 wherein the nylon polymer is combined with
a second nylon polymer, the second nylon polymer differing in
molecular weight or monomer composition.
72. The wipe of claim 66 wherein the additive comprises a
fluoropolymer.
73. The wipe of claim 65 wherein the condensation polymer comprises
a polyurethane polymer.
74. The wipe of claim 65 wherein the condensation polymer comprises
an aromatic polyamide.
75. The wipe of claim 65 wherein the condensation polymer comprises
a polyarylate.
76. The wipe of claim 70 wherein the nylon copolymer comprises
repeating units derived from a cyclic lactam, a C.sub.6-10 diamine
monomer and a C.sub.6-10 diacid monomer.
77. The wipe of claim 65 wherein the nanofiber comprises about 2 to
25 wt % of an additive comprising a resinous material having a
molecular weight of about 500 to 3000 and the additive is miscible
in the polymer.
78. The wipe of claim 77 wherein additive comprises an aromatic
character.
79. A film forming polishing wipe conformable to a surface, the
wipe comprising a film forming composition, at least a flexible
substrate and a nanofiber layer, the flexible substrate comprising
a layer having a thickness of about 0.01 to 0.2 cm, the nanofiber
layer comprising fiber having a diameter of about 0.001 to about 5
microns, a basis weight of about 0.0012 to about 3.5
grams-m.sup.-2, the layer having a pore size less than about 20
microns.
80. The wipe of claim 79 wherein the wipe comprises a woven fabric
having a thickness of about 0.02 to 0.1 cm and a nanofiber layer
having a fiber size of about 0.05 to 0.5 micron and a basis weight
of about 0.1 to 0.5 gm-m.sup.-2.
81. The wipe of claim 79 wherein the wipe comprises a cellulosic
non-woven having a thickness of about 0.02 to 0.1 cm and a
nanofiber layer having a fiber size of about 0.05 to 0.5 micron and
a basis weight of about 0.1 to 0.5 gm-m.sup.-2.
82. The wipe of claim 79 wherein the wipe comprises a blended
polymer cellulosic non-woven having a thickness of about 0.02 to
0.1 cm and a nanofiber layer having a fiber size of about 0.05 to
0.5 micron and a basis weight of about 0.1 to 0.5 gm-m.sup.-2.
83. The wipe of claim 79 wherein the substrate comprises a
non-woven fabric made from both cellulosic and polymeric fiber
materials.
84. The wipe of claim 79 wherein the wipe is combined with a
tackifier.
85. The wipe of claim 79 wherein the wipe has stiffness measured
according to TAPPI T 543 om-00: "Bending Resistance of Paper
(Gurley-Type Tester)" less than 300 milligrams.
86. The wipe of claim 79 wherein the wipe is combined with a liquid
coating composition.
87. The wipe of claim 79 wherein the wipe is combined with an
aqueous coating composition.
88. The wipe of claim 79 wherein the nanofiber comprises an
addition polymer.
89. The wipe of claim 88 wherein the addition polymer additionally
comprises an additive.
90. The wipe of claim 89 wherein the additive comprises a
hydrophobic coating on the fine fiber surface.
91. The wipe of claim 90 wherein the hydrophobic coating has a
thickness of less than 100 .ANG..
92. The wipe of claim 88 wherein the addition polymer comprises a
polyvinyl halide polymer, a polyvinylidene halide polymer or
mixtures thereof.
93. The wipe of claim 88 wherein the addition polymer comprises a
polyvinyl alcohol.
94. The wipe of claim 88 wherein the addition polymer comprises a
fluoropolymer.
95. The wipe of claim 88 wherein the addition polymer comprises a
fluoropolymer elastomer.
96. The wipe of claim 93 wherein the polyvinyl alcohol is
crosslinked with about 1 to 40 wt. % of a crosslinking agent.
97. The wipe of claim 96 wherein the crosslinking agent comprises a
polymer comprising repeating units of acrylic acid, the polymer
having a molecular weight of about 1000 to 5000.
98. The wipe of claim 96 wherein the crosslinking agent comprises a
melamine-formaldehyde resin having a molecular weight of about 1000
to 3000.
99. The wipe of claim 92 wherein the polyvinyl halide is
crosslinked.
100. The wipe of claim 79 wherein the nanofiber comprises
condensation polymer.
101. The wipe of claim 100 wherein the condensation polymer
additionally comprises an additive.
102. The wipe of claim 101 wherein the additive comprises a
hydrophobic coating on the fine fiber surface.
103. The wipe of claim 102 wherein the hydrophobic coating has a
thickness of less than 100 .ANG..
104. The wipe of claim 100 wherein the condensation polymer
comprises a polyester.
105. The wipe of claim 100 wherein the condensation polymer
comprises a nylon polymer.
106. The wipe of claim 105 wherein the nylon polymer is combined
with a second nylon polymer, the second nylon polymer differing in
molecular weight or monomer composition.
107. The wipe of claim 101 wherein the additive comprises a
fluoropolymer.
108. The wipe of claim 100 wherein the condensation polymer
comprises a polyurethane polymer.
109. The wipe of claim 100 wherein the condensation polymer
comprises an aromatic polyamide.
110. The wipe of claim 100 wherein the condensation polymer
comprises a polyarylate.
111. The wipe of claim 105 wherein the nylon copolymer comprises
repeating units derived from a cyclic lactam, a C.sub.6-10 diamine
monomer and a C.sub.6-10 diacid monomer.
112. The wipe of claim 100 wherein the nanofiber comprises about 2
to 25 wt % of an 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.
Description
RELATED APPLICATION
[0001] This application is a continuation-in-part application of
U.S. Ser. No. 10/295,017, filed Nov. 13, 2002, which application is
incorporated herein by reference
FIELD OF THE INVENTION
[0002] The invention is embodied in a surface shape conformable and
flexible wipe having at least two layers of material. The wipe,
comprising a nanofiber layer and a flexible woven or non-woven
fabric substrate, can remove soils in the form of inorganic or
organic particulate, oily or greasy soils, or dispersions of
particulate in liquid. The wipe has a layer specifically designed
to trap or otherwise incorporate finely divided small particle size
soil for efficient removal from a variety of contaminated surfaces.
The wipe can also absorb oily or greasy soils into the fabric
substrate. Further, when used with appropriate liquid (aqueous or
organic) cleaning, dusting or other such compositions, the fine
fiber layer can obtain an improved surface appearance due to the
reduced size of any structure formed from cleaning
compositions.
BACKGROUND OF THE INVENTION
[0003] Both woven and non-woven fabrics have been used for many
years for cleaning and polishing purposes. Such fabrics are
typically manufactured by forming fiber into a woven or non-woven
structure. These fabrics must conform to the contaminated surfaces
for the purposes of either dry wiping (dusting) or wet wiping (with
water or liquid cleaners or polishing composition) particulate,
organic or inorganic soils, from contaminant laden surfaces. Such
particulates are commonly considered soils and their removal is
highly desirable in many environments for maintaining cleanliness,
human health, improved production efficiency or through the removal
of biological, chemical or radioactive contamination. These
materials can also be used to renew or polish surfaces using
finishing compositions to form a shining surface. Generally, the
woven and non-woven fabrics have an absorbent assembly of fibers.
Conventional cloths can often remove particulate at some level of
efficiency and, when used wet, be able to absorb quantities of
liquid material either as a result of liquid contamination or
through the application of liquid cleaners to a soiled surface.
Examples of conventional fabrics include Nankee et al., U.S. Pat.
No. 3,686,024; Lindsey et al., U.S. Pat. No. 4,260,443; Packard et
al., U.S. Pat. No. 4,851,069 and Makoui European Patent Application
No. 35 96 15. In large part, these wipes are cellulosic composites
that interact with water or other aqueous cleaners to obtain
efficient cleaning capacity.
[0004] The prior art has also recognized that a unique type of
finite length fine fiber materials can be included in such
structures. Such structures are shown in Anderson et al., U.S. Pat.
No. 4,100,324; Meitner, U.S. Pat. No. 4,307,143; Anderson et al.,
U.S. Pat. No. 5,651,862 and Torobin, U.S. Pat. No. 6,269,513. These
nanofiber containing structures rely on a technology in which the
nanofibers, in the form of reduced lengths of fiber, are
incorporated and distributed throughout the non-woven or woven
matrix and combined with other fiber in the fiber mass in the wipe.
No discrete fine fiber layer is found in or on the wipe. The fine
fiber inside the layers allegedly improves cleaning properties of
the pad or composite material.
[0005] Our experience with conventional woven and non-woven wipes,
even those containing nanofiber dispersed in the bulk material, is
that these wipes have adequate, conventional cleaning properties.
The wipes, however, often fail to substantially remove small
particulate in a cleaning mode. The large fiber part of these
materials results often in a level of finish formation not
acceptable to users.
[0006] Accordingly, a substantial need exists for new conformable
wipe configurations that are adapted to trapping and removing small
particulate contaminant from surfaces. Such wipes can substantially
improve cleaning efficiency by removing small particulate, soils,
bacteria, chemical and biological contaminants and potentially
radioactive materials as well. Such wipes, with reduced fiber size
can form an improved surface finish by reducing surface
defects.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The wipe structure constituting an aspect of the invention
comprises at least a flexible conformable fabric substrate layer
having discrete sides and a discrete fine fiber layer formed on at
least one side of the substrate.
[0008] The fabric substrate used in making the wipe of the
invention can comprise either a woven or non-woven fabric having a
thickness of about 0.01 to 0.2 cm or about 0.02 to 0.1 cm, made
from natural or synthetic materials. Natural materials include
cotton or flax fibers. Synthetic polymer materials are known in the
art. Many useful fabric substrates comprise a mixed
cellulosic/synthetic, non-woven fabric made by combining cellulosic
fiber with synthetic fibers such as polyolefins, polyesters, etc.
Such fabrics are made by weaving or by adhering a layer of randomly
laid fiber. Fabrics used in such wipes are available woven and
nonwoven materials.
[0009] The fine fiber layer of the invention comprises a layer
having a layer thickness of about 0.05 to 30 millimeters, a fiber
diameter of about 0.05 to 5, a diameter of about 0.05 to 2 microns,
or a diameter of about 0.05 to 0.5 microns, a basis weight of about
0.0012 to 3.5 grams per meter2 and a pore size that ranges from
about 0.5 to 20 microns. The presence of the very small diameter
fine fiber (compared to conventional fibers) permits the fine fiber
to trap or incorporate inorganic particulate and absorb organic
soil in cleaning operations. In polishing operations, the small
dimensions of the fine fiber results in improved surface
characteristics derived from polishing or first coating
applications. The fine fiber layer on the flexible wipe of the
invention provides a web of fibers having a smaller dimension than
conventional cleaning wipes. Such small fibers, when used with a
material that forms a surface finish or coating on a cleaning
surface, can obtain a smoother, shinier, more aesthetically
pleasing appearance. Any finish formed using the fine fiber layer
will have an improved surface finish resulting from the improved
surface characteristics left by the smaller fiber of the fine fiber
layer. The fine fiber forms fewer and smaller defects than larger
fiber wipes. Accordingly, the fine fiber wipes of the invention can
be used in a process that forms an improved finish on a cleanable
surface by contacting the surface with a composition that can form
a coating on the surface, wiping the surface with a fine fiber
layer (either saturated with the composition or with a composition
pre-applied to the surface), distributing the coating and
permitting the coating to form its final improved
characteristic.
[0010] For the purpose of this disclosure, the term "inorganic
particulate" typically refers to finely divided particulate soils
derived from the environment including dust and dirt particulates
having a particle size of about 10.sup.-3 to 10.sup.5 micron, often
10.sup.-2 to 10 micron. The term "organic soils" typically include
soils derived from human occupation, foods, cosmetics, cleaners, or
common organic materials from the human environment. Often, such
organic and inorganic soils can be combined with small particulate
organic matter such as skin cells, hair components, insects and
insect parts, etc.
[0011] One important characteristics of the wipe is the flexibility
of the wipe and the flexibility of the fine fiber layer. While the
polymers of the invention display flexural properties similar to
unfilled polymer, the small fiber diameter gives the fiber on the
wipe a unique flexibility and improved cleaning/polishing
character. Cleaning pressure can bring the fine fiber into intimate
contact with the soil, the surface regardless of its complexity. In
contact with the soils, the unique nature of the fine fiber causes
the fiber to combine with the soils and trap or accumulate soils as
the fiber layer is mechanically stretched, wrapped and changed. In
a polishing mode, the fiber small size can form an improved surface
coating due to the coating having a reduced defect character due
the size of the fiber. Larger conventional fiber leaves larger
defects in the finished coating. In the wipe substrate, many
synthetic and natural fiber materials are available that have
substantial stiffness. Such materials cannot be made sufficiently
flexible to be able to easily comply with complex surfaces faced by
individuals who wish to clean or polish such surfaces. The wipes
should be manufactured from a material that is flexible and easily
conformable to the surface. The term "conformable" means that the
wipe and the fine fiber layer can be placed into contact with a
surface for cleaning proposes even with surfaces that have complex
angled or curved surfaces. Minimal pressure can bring the fine
fiber layer into intimate contact with substantially all surfaces
of a complex article.
BRIEF DESCRIPTION OF THE FIGURES
[0012] FIGS. 1-17 are scanning electron-photo micrographs (SEMS) of
wipes with a nanofiber layer that have been used to remove both
inorganic particulate and organic soils form a automotive glass
surface or a polymeric dash surface. The figures show that the
fibers can trap both organics and inorganic soils. Small
particulate is enmeshed by the fiber while the organic soils coat
the fibers on contact between the fiber and soil. The interaction
of the surface and soil with the fine fiber layer changes the
conformation of the fiber layer as the fibers trap particulate and
accumulate organic soil.
DETAILED DISCUSSION OF THE INVENTION
[0013] The wipe of the invention comprises at least a two-layer
structure. The first layer comprises a flexible, conformable, woven
or non-woven fabric layer. The second layer comprises a layer of a
nanofiber. The major difference between the fabric and the
nanofiber is in the fiber size and the thickness of the layers. The
conformable wipe can be applied to any flat, convex, concave or
complex surface for the purpose of removing inorganic or organic
soils or for the purpose of restoring a shiny, pleasing appearance
to the surface.
[0014] For the purpose of this patent application, the term "fine
fiber" refers to a fiber having an indeterminate length but a width
of less than about 5 microns often, less than about 2 and often
less than about 1 micron. In the wipe, the fine fiber is formed
into a randomly oriented mesh of fiber in a layer that
substantially covers a surface of the fabric substrate. Preferred
fine fiber layer add-on parameters are as follows:
1 Dimensions Range Layer thickness (.mu.m) 0.1 to 5 Solidity % 5 to
40 Density (gm-cm.sup.-3) 0.9 to 1.6 (1.2 to 1.4) Basis wt.
(mg-cm.sup.-2) 1.2 .times. 10.sup.-4 to 3.5
[0015] In one embodiment, a reduced amount but useful add-on amount
of fine fiber would be a 0.1 to 1.75 micron thick layer of 5% to
40% solidity fiber layer (95% to 60% void fraction). In this case
the basis weight is 4.times.10.sup.-4 to 0.11 mg-cm.sup.-2.
[0016] In another embodiment, an add-on amount of fine fiber would
a 0.75 to 1.25 micron thick layer of 15% to 25% solidity fiber
layer (85% to 75% void fraction) In this case the basis weight is
1.0.times.10.sup.-2 to 0.05 mg-cm.sup.-2.
[0017] In a final embodiment, the upper end of the add-on amount of
fine fiber would be a 0.1-3 micron thick layer of 10% to 40%
solidity fiber layer (90% to 60% void fraction). In this case the
basis weight is 4.times.10.sup.-4 to 0.2 mg-cm.sup.-2.
[0018] For the purpose of this disclosure, the term "separate from
fiber layer" is defined to mean that in the wipe structure, having
a substantially sheet-like substrate, the fine fiber layer
substantially covers the fabric substrate. The fine fiber layers
can in theory be manufactured in one processing step that covers
the entirety of one or both surfaces of a two sided flexible
fabric. In most applications, we envision that a first fine fiber
layer will be formed on one fabric side.
[0019] For the purpose of this disclosure, the term "fine fiber
layer pore size or fine fiber web pore size" refers to a space
formed between the intermingled fibers in the fine fiber layer.
[0020] For the purpose of this disclosure, the term "fabric or
fabric substrate" refers to a woven or non-woven sheet like
substrate, having a thickness of about 0.1 to 5 millimeters.
[0021] The wipe includes at least a fine fiber or nanofiber layer
in combination with a fabric substrate material in a mechanically
stable structure. The fine fiber layer must be sufficiently
mechanically and chemically stable to obtain cleaning or polishing
through interaction with soil and surface. These layers together
provide excellent organic absorption, surface conformation, and
high particle capture. After use the polymer fiber or fiber web may
be substantially changed in physical conformation. Mechanical
forces of wiping can substantially consolidate the fine fiber layer
and distort the fine fiber substantially form its initial form. The
wipes of the invention are manufactured by spinning fine fiber and
then forming an interlocking web of microfiber on a porous wipe
fabric substrate. In the spinning process the fiber can form
physical bonds between fibers to interlock the fiber mat into an
integrated layer on the fabric. Such a material can then be
fabricated into the desired wipe format such as a dry or wet
wipe.
[0022] The invention relates to polymeric compositions with
improved properties that can be used in a variety of applications
including the formation of nanofibers, fiber webs, fibrous mats,
etc. The fine fibers that comprise the micro- or nanofiber
containing layer of the invention can be fiber and can have a
diameter of about 0.001 to 2 micron, preferably 0.05 to 0.5 micron.
The thickness of the typical fine fiber layer ranges from about 1
to 100 times the fiber diameter with a basis weight ranging from
about 4.5.times.10.sup.-4 to 2 mg-cm.sup.-2.
[0023] The fine fiber-containing wipe of the invention can be used
to clean virtually any soil or contaminated surfaces. Such surfaces
can include surfaces in the home including metal, plastic, wood,
glass or other common household surface. Surfaces found in industry
including process equipment, instrumentation, computer equipment,
communications equipment, etc. Surfaces common in the hospital
environment such as instrumentation, beds, gurneys, operating
theater environments, laboratory environments, etc. Other important
surfaces include surfaces that may be contaminated by chemical or
biological agents, radioactive agents derived from weapon research,
manufacture or terrorist threat. Other surfaces can be surfaces of
parts of the human body. The wipes can be used for medical,
hygienic or cosmetic purposes. Such applications include baby
wipes, medical wipes; cosmetic wipes facial wipes or flushable
materials. Such surfaces can be substantially planar, formed into
simple curves or configured into complex shapes having complex
curvature, sharp edges, corners or grooves. Such surfaces can be
contaminated with either organic or inorganic soils or combinations
thereof. As a result, the wipe of the invention must be flexible
and conformable to any surface requiring cleaning or polishing. The
wipe must be sufficiently flexible such that the nanofiber layer
can contact substantially the entire surface during cleaning
operations. The fine fiber layer must come into contact with
organic, inorganic or particulate soils in order to permit the fine
fiber to obtain the organic soils as a coating on the fiber and to
enmesh the particulate soil in the fine fiber structure. As can be
seen in the photomicrographs shown in FIGS. 1 through 17 of the
invention, the fine fiber materials of the invention are engineered
such that the fiber can enmesh particulate soil and can absorb
organic soil onto the surface of the fiber for cleaning purposes.
This property is the result of both the chemical nature of the fine
fiber and its size and distribution in the fine fiber layer.
[0024] Polymeric materials have been fabricated in non-woven and
woven fabrics, fibers, microfibers and nanofibers. The polymer
materials that can be used in the fine fiber or the polymeric fiber
fabric compositions of the invention include both addition polymer
and condensation polymer materials such as polyolefin, polyacetal,
polyamide, polyester, cellulose ether and ester, polyalkylene
sulfide, polyarylene oxide, polysulfone, modified polysulfone
polymers and mixtures thereof. Preferred materials that fall within
these generic classes include polyethylene, polypropylene,
poly(vinylchloride), polymethylmethacrylate (and other acrylic
resins), polystyrene, and copolymers thereof (including ABA type
block copolymers), poly(vinylidene fluoride), poly(vinylidene
chloride), polyvinylalcohol in various degrees of hydrolysis (87%
to 99.5%) in crosslinked and non-crosslinked forms. Preferred
addition polymers tend to be glassy (a Tg greater than room
temperature). This is the case for polyvinylchloride and
polymethylmethacrylate, polystyrene polymer compositions or alloys
or low in crystallinity for polyvinylidene fluoride and
polyvinylalcohol materials. One class of polyamide condensation
polymers include nylon materials. The term "nylon" is a generic
name for all long chain synthetic polyamides. Typically, nylon
nomenclature includes a series of numbers such as in nylon-6,6
which indicates that the starting materials are a C.sub.6 diamine
and a C.sub.6 diacid (the first digit indicating a C.sub.6 diamine
and the second digit indicating a C.sub.6 dicarboxylic acid
compound). Another nylon can be made by the polycondensation of
epsilon caprolactam in the presence of a small amount of water.
This reaction forms a nylon-6 (made from a cyclic lactam--also
known as episilon-aminocaproic acid) that is a linear polyamide.
Further, nylon copolymers are also contemplated. Copolymers can be
made by combining various diamine compounds, various diacid
compounds and various cyclic lactam structures in a reaction
mixture and then forming the nylon with randomly positioned
monomeric materials in a polyamide structure. For example, a nylon
6,6-6,10 material is a nylon manufactured from hexamethylene
diamine and a C.sub.6 and a C.sub.10 blend of diacids. A nylon
6-6,6-6,10 is a nylon manufactured by copolymerization of
epsilonaminocaproic acid, hexamethylene diamine and a blend of a
C.sub.6 and a C.sub.10 diacid material.
[0025] Block copolymers are also useful in the process of this
invention. One example is an ABA (styrene-EP-styrene) or AB
(styrene-EP) polymer. Examples of such block copolymers are
Kraton.RTM. type of styrene-b-butadiene and styrene-b-hydrogenated
butadiene (ethylene propylene), Pebax.RTM. type of
e-caprolactam-b-ethylene oxide, Sympatex.RTM. polyester-b-ethylene
oxide and polyurethanes of ethylene oxide and isocyanates.
[0026] Addition polymers like polyvinylidene fluoride, syndiotactic
polystyrene, copolymer of vinylidene fluoride and
hexafluoropropylene, polyvinyl alcohol, polyvinyl acetate,
amorphous addition polymers, such as poly(acrylonitrile) and its
copolymers with acrylic acid and methacrylates, polystyrene,
poly(vinyl chloride) and its various copolymers, poly(methyl
methacrylate) and its various copolymers, can be solution spun with
relative ease because they are soluble at low pressures and
temperatures. However, highly crystalline polymer like polyethylene
and polypropylene require high temperature, high pressure solvent
if they are to be solution spun. Therefore, solution spinning of
the polyethylene and polypropylene is very difficult. Electrostatic
solution spinning is one method of making nanofibers and
microfiber.
[0027] Fluoropolymer materials can be used in the fine fiber layers
of the invention. Fluoropolymer elastomers are preferred. The most
commonly available Fluoropolymer elastomer is the Viton.RTM.
(DuPont) elastomeric composition. The preferred use of the
fluoropolymer elastomer is in the dual layer of fine fiber. Such
dual layers can comprise a fabric substrate, a first layer of
fluoropolymer elastomer fine fiber followed by a second layer of a
second fine fiber composition.
[0028] Viton exhibits good resistance to most oils, chemicals,
solvents, and halogenated hydrocarbons, and an excellent resistance
to ozone, oxygen, and weathering. Also referred to as
fluoroelastomers, fluorocarbon compounds are thermoset elastomers
containing fluorine. Fluorocarbons make excellent general-purpose
fibers thanks to their exceptional resistance to chemicals, oils,
and temperature extremes (-15.degree. F. to +400.degree. F.).
Specialty compounds can further extend the low temperature limit
down to -22.degree. F. for dynamic seals and -40.degree. F. in
static applications. Fluorocarbons typically have good temperature
performance, and resistance to ozone and sunlight. Over the last
five decades, this remarkable combination of properties has
prompted the use of fluorocarbon seals in a variety of demanding
sectors. The useful temperature range of the materials is about
-10.degree. F. to +400.degree. F. in continuous service.
[0029] Suitable haloelastomers for use herein include any suitable
halogen containing elastomer such as chloroelastomers,
bromoelastomers, fluoroelastomers, or mixtures thereof.
Fluoroelastomer examples include those described in detail in
Lentz, U.S. Pat. No. 4,257,699, as well as those described in Eddy
et al., U.S. Pat. No. 5,017,432 and Ferguson et al., U.S. Pat. No.
5,061,965. The disclosures of each of these patents are totally
incorporated herein by reference. The original commercial
fluorocarbon, Viton.RTM. A, is the general-purpose type and is
still the most widely used. It is a copolymer of vinylidene
fluoride (VF2) and hexafluoropropylene (HFP). Generally composed of
60-70% fluorine, Viton A compounds offer excellent resistance
against many automotive and aviation fuels, as well as both
aliphatic and aromatic hydrocarbon process fluids and chemicals.
Viton A compounds are also resistant to engine lubricating oils,
aqueous fluids, steam, and mineral acids. Viton B fluorocarbons are
terpolymers combining tetrafluoroethylene (TFE) with VF2 and HFP.
Depending on the exact formulation, the TFE partially replaces
either the VF2 (which raises the fluorine level to approximately
68%) or the HFP (keeping the fluorine level steady at 66%). Viton B
compounds offer better fluids resistance than the Viton A
copolymers. Viton GF fluorocarbons are tetrapolymers composed of
TFE, VF2, HFP, and small amounts of a cure site monomer (Csm).
Presence of the cure site monomer allows peroxide curing of the
compound, which is normally 70% fluorine. As the most fluid
resistant of the FKM types, Viton GF compounds offer improved
resistance to water, steam, and acids.
[0030] Viton GFLT fluorocarbons are similar to Viton GF, except
that perfluoromethylvinyl ether (PMVE) is used in place of HFP. The
"LT" in Viton GFLT stands for "low temperature." The combination of
VF2, PMVE, TFE, and a cure site monomer is designed to retain both
the superior chemical resistance and high heat resistance of the
G-series fluorocarbons. In addition, Viton GFLT compounds
(typically 67% fluorine) offer the lowest swell and the best low
temperature properties of the types discussed here. Viton GFLT can
seal in a static situation down to approximately -40.degree. F. A
brittle point of -50.degree. F. can be achieved through careful
compounding.
[0031] As described therein, the next generation of these
fluoroelastomers include copolymers and terpolymers of
vinylidenefluoride, hexafluoropropylene and tetrafluoroethylene,
which are known commercially under various designations as
VITO.RTM. A, VITON.RTM. E, VITON.RTM. E60C, VITON.RTM. E45,
VITON.RTM. E430, VITON.RTM. B910, VITON.RTM. GH, VITON.RTM. B50,
VITON.RTM. E45, and VITON.RTM. GF. The VITON designation is a
Trademark of E.I. DuPont de Nemours, Inc. Two preferred known
fluoroelastomers are (1) a class of copolymers of
vinylidenefluoride, hexafluoropropylene and tetrafluoroethylene,
(such as a copolymer of vinylidenefluoride and hexafluoropropylene)
known commercially as VITOA.RTM. A, (2) a class of terpolymers of
vinylidenefluoride, hexafluoropropylene and tetrafluoroethylene
known commercially as VITON.RTM. B, and (3) a class of
tetrapolymers of vinylidenefluoride, hexafluoropropylene,
tetrafluoroethylene and a cure site monomer. The cure site monomer
can be those available from DuPont such as
4-bromoperfluorobutene-1,1,1-dihydro-4-bromoperfluorobutene-1,3-bromoperf-
luoropropene-1,1,1-dihydro-3-bromoperfluoropropene-1, or any other
suitable, known, commercially available cure site monomer. In
another preferred embodiment, the fluoroelastomer is a tetrapolymer
having a relatively low quantity of vinylidenefluoride. An example
is VITON.RTM. GF, available from E.I. DuPont de Nemours, Inc. The
VITON.RTM. GF has 35 weight percent of vinylidenefluoride, 34
weight percent of hexafluoropropylene and 29 weight percent of
tetrafluoroethylene with 2 weight percent cure site monomer.
Typically, these fluoroelastomers are cured with a nucleophilic
addition curing system, such as a bisphenol crosslinking agent with
an organophosphonium salt accelerator as described in further
detail in the above-referenced Lentz patent and in U.S. Pat. No.
5,017,432. The fluoroelastomer is generally cured with bisphenol
phosphonium salt, or a conventional aliphatic peroxide curing
agent. Some of the aforementioned haloelastomers and others that
can be selected include VITON.RTM. E45, AFLAS.RTM., FLUOREL.RTM.,
FLUOREL.RTM. II, TECHNOFLON.RTM. and the like
commercially-available haloelastomers. Similar polymers are
available from 3M as Dyneon products.
[0032] We have also found a substantial advantage to forming
polymeric compositions comprising two or more polymeric materials
in polymer admixture, alloy format or in a crosslinked chemically
bonded structure. We believe such polymer compositions improve
physical properties by changing polymer attributes such as
improving polymer chain flexibility or chain mobility, increasing
overall molecular weight and providing reinforcement through the
formation of networks of polymeric materials.
[0033] In one embodiment of this concept, two related polymer
materials can be blended for beneficial properties. For example, a
high molecular weight polyvinylchloride can be blended with a low
molecular weight polyvinylchloride. Similarly, a high molecular
weight nylon material can be blended with a low molecular weight
nylon material. Further, differing species of a general polymeric
genus can be blended. For example, a high molecular weight styrene
material can be blended with a low molecular weight, high impact
polystyrene. A Nylon-6 material can be blended with a nylon
copolymer such as a Nylon-6; 6,6; 6,10 copolymer. Further, a
polyvinylalcohol having a low degree of hydrolysis such as a 87%
hydrolyzed polyvinylalcohol can be blended with a fully or
superhydrolyzed polyvinylalcohol having a degree of hydrolysis
between 98 and 99.9% and higher. All of these materials in
admixture can be crosslinked using appropriate crosslinking
mechanisms. Nylons can be crosslinked using crosslinking agents
that are reactive with the nitrogen atom in the amide linkage.
Polyvinylalcohol materials can be crosslinked using hydroxyl
reactive materials such as monoaldehydes, such as formaldehyde,
ureas, melamine-formaldehyde resin and its analogues, boric acids
and other inorganic compounds. dialdehydes, diacids, urethanes,
epoxies and other known crosslinking agents. Crosslinking
technology is a well known and understood phenomenon in which a
crosslinking reagent reacts and forms covalent bonds between
polymer chains to substantially improve molecular weight, chemical
resistance, overall strength and resistance to mechanical
degradation.
[0034] The fine fiber can be made of a polymer material or a
polymer plus additive. One preferred mode of the invention is a
polymer blend comprising a first polymer and a second, but
different polymer (differing in polymer type, molecular weight or
physical property) that is conditioned or treated at elevated
temperature. The polymer blend can be reacted and formed into a
single chemical specie or can be physically combined into a blended
composition by an annealing process. Annealing implies a physical
change, like crystallinity, stress relaxation or orientation.
Preferred materials are chemically reacted into a single polymeric
specie such that a Differential Scanning Calorimeter analysis
reveals a single polymeric material. Such a material, when combined
with a preferred additive material, can form a surface coating of
the additive on the microfiber that provides oleophobicity,
hydrophobicity or other associated improved stability when
contacted with high temperature, high humidity and difficult
operating conditions. The fine fiber of the class of materials can
have a diameter of about 0.01 to 5 microns. Such microfibers can
have a smooth surface comprising a discrete layer of the additive
material or an outer coating of the additive material that is
partly solubilized or alloyed in the polymer surface, or both.
Preferred materials for use in the blended polymeric systems
include nylon 6; nylon 66; nylon 6-10; nylon (6-66-610) copolymers
and other linear generally aliphatic nylon compositions. A
preferred nylon copolymer resin (SVP-651) was analyzed for
molecular weight by the end group titration. (J. E. Walz and G. B.
Taylor, determination of the molecular weight of nylon, Anal. Chem.
Vol. 19, Number 7, pp 448-450 (1947). A number average molecular
weight (M.sub.n) was between 21,500 and 24,800. The composition was
estimated by the phase diagram of melt temperature of three
component nylon, nylon 6 about 45%, nylon 66 about 20% and nylon
610 about 25%. (Page 286, Nylon Plastics Handbook, Melvin Kohan ed.
Hanser Publisher, New York (1995)).
[0035] Reported physical properties of SVP 651 resin are:
2 Property ASTM Method Units Typical Value Specific Gravity D-792
-- 1.08 Water Absorption D-570 % 2.5 (24 hr immersion) Hardness
D-240 Shore D 65 Melting Point DSC .degree. C. (.degree. F.) 154
(309) Tensile Strength D-638 MPa (kpsi) 50 (7.3) @ Yield Elongation
at Break D-638 % 350 Flexural Modulus D-790 MPa (kpsi) 180 (26)
Volume Resistivity D-257 ohm-cm 10.sup.12
[0036] We have found that additive materials can significantly
improve the properties of the polymer materials in the form of a
fine fiber. The resistance to the effects of heat, humidity,
impact, mechanical stress and other negative environmental effect
can be substantially improved by the presence of additive
materials. We have found that while processing the microfiber
materials of the invention, that the additive materials can improve
the oleophobic character, the hydrophobic character and can appear
to aid in improving the chemical stability of the materials. We
believe that the fine fibers of the invention in the form of a
microfiber are improved by the presence of these oleophobic and
hydrophobic additives as these additives form a protective layer
coating, ablative surface or penetrate the surface to some depth to
improve the nature of the polymeric material. We believe the
important characteristics of these materials are the presence of a
strongly hydrophobic group that can preferably also have oleophobic
character. Strongly hydrophobic groups include fluorocarbon groups,
hydrophobic hydrocarbon surfactants or blocks and substantially
hydrocarbon oligomeric compositions. These materials are
manufactured in compositions that have a portion of the molecule
that tends to be compatible with the polymer material affording
typically a physical bond or association with the polymer while the
strongly hydrophobic or oleophobic group, as a result of the
association of the additive with the polymer, forms a protective
surface layer that resides on the surface or becomes alloyed with
or mixed with the polymer surface layers. For 0.2-micron fiber with
10% additive level, the surface thickness is calculated to be
around 50 .ANG., if the additive has migrated toward the surface.
Migration is believed to occur due to the incompatible nature of
the oleophobic or hydrophobic groups in the bulk material. A 50
.ANG. thickness appears to be reasonable thickness for protective
coating. For 0.05-micron diameter fiber, 50 .ANG. thickness
corresponds to 20% mass. For 2 microns thickness fiber, 50 .ANG.
thickness corresponds to 2% mass. Preferably the additive materials
are used at an amount of about 2 to 25 wt. %. Oligomeric additives
that can be used in combination with the polymer materials of the
invention include oligomers having a molecular weight of about 500
to about 5000, preferably about 500 to about 3000 including
fluoro-chemicals, nonionic surfactants and low molecular weight
resins or oligomers. A useful material for use as an additive
material in the compositions of the invention is tertiary
butylphenol oligomers. Such materials tend to be relatively low
molecular weight aromatic phenolic resins. Such resins are phenolic
polymers prepared by enzymatic oxidative coupling. The absence of
methylene bridges result in unique chemical and physical stability.
These phenolic resins can be crosslinked with various amines and
epoxies and are compatible with a variety of polymer materials.
Examples of these phenolic materials include Enzo-BPA,
Enzo-BPA/phenol, Enzo-TBP, Enzo-COP and other related phenolics
were obtained from Enzymol International Inc., Columbus, Ohio.
[0037] The wipe structures of the invention can be improved using a
tackifying resin. The presence of an effective amount of tackifying
resin on the substrate or associated with the nanofibers of the
invention can improve the tendency of the overall wipe to collect
and remove particulate from a soiled surface. Tackifying resins are
generally known to add tack in formulated systems. Polymers
formulated with a tackifier can obtain temporary or permanent tack
to a surface. Tackifying resins are low molecular weight amorphous
polymers. Tackifying resins have been applied to formulated
adhesives, inks, chewing gums, and other formulated materials. In
formulated adhesives, resins are used to generate tack and
specifically, adhesion to substrate surfaces. Tackifiers are
generally used in combination with a high molecular weight
polymeric material that forms the backbone of the adhesive and
generate adhesion to substrate surfaces and cohesive character
within the polymer and adhesive mass. Formulators typically use
such tackifying resins to create the best balance between adhesion
and cohesion to optimize adhesive formulations. Tackifying resins
can be divided into three groups: hydrocarbon resin, rosin
materials and terpene materials. Hydrocarbon resins are typically
based on petroleum feed stocks polymerized into low molecular
weight materials. Petroleum feed stocks are typically olefinic
materials derived from the refining process and are often easily
polymerized into low molecular amorphous polymers. Some other
ydrocarbon resins are typically based on natural feed stocks
obtained from natural plant sources such as pine trees. Terpene
resins are generally derived from natural sources, wood turpentine
or from Kraft sulfate pulping processes. Rosin (also known as one
of the "naval stores") is one of the oldest raw materials in the
adhesive industry. Rosin can be used as derived from natural
sources or can be converted into a rosin ester. Three types of
rosins are used for resin manufacture. Gum rosin, wood rosin and
tall oil rosin are all generated from pine tree and other arboreal
sources. Rosin materials, unlike hydrocarbon resins, are not truly
polymeric in nature. In fact, they are a blend of different
molecules including abietic, pimaric, and other materials derived
from terpene-like natural products. The carboxylic functionality in
these rosin materials are often esterified using various alcohol
materials. The softening point of the subsequent ester can be
modified using a selected alcohol material. Often, these resins are
esterified with glycerol, pentaerythritol, methanol, triethylene
glycol, and other similar relatively low molecular weight mono-,
di-, tri- and polyhydroxy alcohol materials. Terpene resins are
typically based on resins formed by cationic polymerization of
alpha-pinene, beta-pinene and d-limonene feed stocks. These
generally pinene feed stocks produce resins of low color and range
of softening points.
[0038] Low molecular weight hydrocarbon resins can be used as
tackifying materials. Hydrocarbon resins are typically made by
polymerizing C.sub.5 aliphatic resins, C.sub.9 aromatic resins,
dicyclopentadiene cycloaliphatic resins or mixtures thereof. Feed
stocks for manufacturing these resins are typically derived from
petroleum feed stocks containing isoprene, cyclopentadiene,
dicyclopentadiene, piperylene and other C.sub.5 feed stocks. The
primary monomers used in C.sub.5 resins include various
pentadienes, dicyclopentadienes and cyclopentene. In essence,
C.sub.5 resins are aliphatic materials having both saturated and
unsaturated carbon atoms. C.sub.9 resins typically are at least
partially aromatic in nature since the C.sub.9 resins often contain
vinyl toluene monomers, dicyclopentadiene monomers, indene
monomers, methylstyrene monomers, styrene monomers and methylindene
monomers. C.sub.9 resins are available in a wide variety of
softening points and molecular weights. Hydrogenating these
hydrocarbon resins produces another class of hydrocarbon resins
that are improved in color and temperature stability of the resins.
Hydrogenating these resins removes color and saturates the vinyl
residues in the polymer forming substantially saturated carbon
atoms. Further, partial and selective hydrogenation can be used to
produce a variety of materials with broad saturated carbon,
aliphatic carbon and aromatic carbon, compatibility and good
thermal and chemical stability. These tackifying resins can be
characterized with color, softening point, molecular weight, melt
viscosity, thermal stability and compatibility. The preferred
resins for use in the wipes of the application are those resins
with low odor, water white to low color, storage stability and
compatibility with the fine fiber material and the cellulosic or
other substrate material.
[0039] An extremely wide variety of flexible fabric materials exist
for different cleaning and polishing applications. The durable
nanofibers and microfibers described in this invention can be added
to any of the fabrics. These fabrics can be woven or non-woven. The
fabrics can be single layer or multiplayer. Each layer can comprise
a single component woven or non-woven fiber or a blended, woven or
non-woven fiber. The fabric layers can be combined with an interior
non-fiber layer such as a sponge, a scrubbing mesh layer, a film
barrier layer or a reservoir layer. The fabrics can be combined
with a handle, support or a block to aid in cleaning or polishing.
The wipes described in this invention can also be used to
substitute for existing fabric wiping materials giving the
significant advantage of improved performance. Cleaning and
polishing is improved due to their small diameter, while exhibiting
greater durability.
[0040] The wipe construction according to the present invention
includes a first layer of a permeable fabric substrate having a
first surface. A first layer of fine fiber is secured to the first
surface of the first layer of fabric. Preferably the first layer of
fabric comprises fibers having an average diameter of at least 10
microns, typically and preferably about 12 (or 14) to 30 microns.
Also preferably the first layer of permeable fabric comprises a
layer having a basis weight of no greater than about 100
grams/meter.sup.2, preferably about 40 to 80 g/m.sup.2, and most
preferably at least 20 g/m.sup.2. Preferably the first layer of
permeable fabric is at least -0.008 inch (200 microns) thick, and
typically and preferably is about 0.01 to 0.05 inch (10.sup.3
microns) thick.
[0041] The microfiber or nanofiber of the unit can be formed by the
common electrostatic spinning process. Barris, U.S. Pat. No.
4,650,506, details the apparatus and method of the electro spinning
process and is expressly incorporated herein by reference.
Apparatus used in such process includes a reservoir in which the
fine fiber forming polymer solution is contained, a pump and a
rotary type emitting device or emitter to which the polymeric
solution is pumped and applied. The emitter generally consists of a
rotating portion. The rotating portion then obtains polymer
solution from the reservoir, and as it rotates in the electrostatic
field, the electrostatic field, as discussed below, accelerates a
droplet of the solution toward the collecting fabric surface.
Facing the emitter, but spaced apart therefrom, is a substantially
planar grid upon which the collecting surface (i.e. fabric or
multilayer of multifiber fabric is positioned. Air can be drawn
through the grid. The collecting surface is positioned adjacent
opposite ends of grid. A high voltage electrostatic potential is
maintained between emitter and grid by means of a suitable
electrostatic voltage source.
[0042] In use, the polymer solution is pumped to the rotating
portion from reservoir. The electrostatic potential between grid
and the emitter imparts a charge to the material that cause liquid
to be emitted therefrom as thin fibers which are drawn toward grid
where they arrive and are collected on substrate fabrics. In the
case of the polymer in solution, solvent is evaporated off the
fibers during their flight to the grid; therefore, the fibers
arrive at the fabric. The fine fibers bond to the fabric fibers
first encountered at the grid. Electrostatic field strength is
selected to ensure that the polymer material as it is accelerated
from the emitter to the fabric; the acceleration is sufficient to
render the material into a very thin microfiber or nanofiber
structure. Increasing or slowing the advance rate of the collecting
fabric can deposit more or less emitted fibers on the forming
fabric, thereby allowing control of the thickness of each layer
deposited thereon.
[0043] The wipe of the invention can be pre-moistened (i.e.)
combined with a liquid material and packaged in a container that
maintains the wipe inn its pre-moistened condition. The container
can comprise a single use envelope or a multiuse pop-up dispenser
or related containers. The liquid materials can include cleaners,
disinfecting solutions, decontaminating solutions, coating
solutions, wax coating solutions, cosmetic solutions, human
deodorant solutions, facial moisturizers, facial cleaners, make-up
removing solutions and other materials. Virtually any liquid
cleaner composition or composition that can lay down a smooth
coating can be combined with the wipes of the invention.
[0044] The liquid material used for the wipe of the invention can
be an aqueous based or solvent based material. Aqueous based
materials are typically manufactured by combining the active
ingredient or formulation in an aqueous base. The aqueous base of
the material can include solvent materials that are soluble or
dispersible in the aqueous media. Such liquid materials used in the
wipes of the invention can also be based on solvent chemistry. Such
solvents include alcohol, light petroleum distillate, ketones,
ethers and other typically volatile solvent materials. Such liquids
can also contain some small proportion of an aqueous material that
can be either dissolved or suspended in the solvent solution.
[0045] The liquid compositions of the invention can include
surfactant materials, chelator materials, disinfectants,
sanitizers, bleaches, lubricants, and other active materials that
can act to either remove soil from surfaces or to provide a coating
on the clean surfaces after soil removal. One important embodiment
of the wipe of the invention includes a wipe that can form a useful
coating on surfaces. Such coatings can comprise a wax, a polymeric
material, a silicone wax or other coating material. One important
advantage of the wipes of the invention is the nanofiber material
on the wipe can obtain an improved surface characteristic due to
the small fiber size of the wipe fine fiber layer. As the coating
material is laid down by the wipe during cleaning or cleaning and
coating, the fine fiber size tends to form a coating layer with
substantially reduced defect size in the coating layer resulting in
an improved surface gloss or smoothness. Glass cleaner materials
can include isopropanol and ammonium hydroxide and ether solvents
such as 2-butoxyethanol and ethylene glycol n-alkyl ether. A polish
and cleaner can include paraffinic hydrocarbon solvent, silicone,
naphtha solvent (petroleum distillate). Skin cleaner can include
water, propylene glycol, PEG-75 Lanolin, Disodium anionic
surfactant, Polysorbate materials, Methylparaben,
2-Bromo-2-Nitropropane-1, 3-Diol, Fragrance, etc. Facial cleaner
wipes can include water, alcohol (10%), butylene glycol,
laureth-(EO).sub.x nonionic, phenoxyethanol, salicylic acid,
panthenol, propylene glycol, PEG-7, glyceryl cocoate, fragrance,
PEG-substituted hydrogenated castor oil, disodium EDTA, benzoic
acid, fragrance, menthol, t-butyl alcohol, etc. Hard surface
cleaner wipes can contain quaternary ammonium compounds. Make-up
remover wipes can include water, alkylene glycol, glycerin, herbal
extract, vitamin-E acetate, aloe vera, panthenol, ginseng (panax
ginseng) extract, anionic surfactant, benzyl alcohol, PEG-40
hydrogenated castor oil, alkylene glycol, polysorbate 20,
fragrance, citric acid and DMDM hydantoin. Disinfectant wipes can
include sodium hypochlorite, ethyl alcohol, Quats, etc.
EXPERIMENTAL
[0046] Examples 1,2 and 3 show the preparation of a nanofiber layer
on a wipe substrate. The wipe is tested for cleaning properties on
automotive surfaces to test the cleaning properties of the material
with organic and inorganic particulate soil.
[0047] The wipe substrate material used for the following examples
was made from a blend of cellulose and polypropylene fibers,
blended in such a way as to make one side of the material
predominantly cellulose, while the other side of the material is
predominantly polypropylene. The composite material has a basis
weight of approximately 58 grams per square meter and a thickness
of approximately 0.016 inch.
Example 1
[0048] Polyamide fibers were electrospun onto the
polypropylene-rich side of a blended fiber wipes material (blend of
polypropylene and cellulose). The fiber size was 0.25 micron having
a basis weight of the nanofiber application was approximately 0.21
g-m.sup.-2. The resulting material was then used to wipe the dash
panel of a 1995 Ford Contour (nanofiber side in contact with the
windshield), by swiping the material across the dash panel, back
and forth, 3 times in an approximate 14" path. The SEM's and
analysis associated with this test are shown in FIGS. 1-4.
Example 2
[0049] Polyamide fibers were electrospun onto the
polypropylene-rich side of a blended fiber wipes material (blend of
polypropylene and cellulose). The basis weight of the nanofiber
application was approximately 0.21 g-m.sup.-2, with a fiber size of
approximately 0.25 microns. The resulting material was then used to
wipe the interior windshield of a 1995 Ford Contour (nanofiber side
in contact with the windshield), by wiping in a circular motion
(approximate 8" diameter circle) 3 times, followed by wiping back
and forth over the same area of the windshield 3 times, in a 10"
path. The SEM's and analysis associated with this test are FIGS.
5-11.
Example 3
[0050] Polyamide fibers were electrospun onto the cellulose-rich
side of a blended fiber wipes material (blend of polypropylene and
cellulose). The basis weight of the nanofiber application was
approximately 0.21 g-m.sup.-2, with a fiber size of approximately
0.25 microns. The resulting material was then used to wipe the dash
panel of a 1995 Ford Contour (nanofiber side in contact with the
windshield), by swiping the material across the dash panel, back
and forth, 3 times in an approximate 14" path. The scanning electro
micrographs and analysis associated with this test are shown in
FIGS. 12-17.
Automotive Dash Testing
FIGS. 1-4
[0051] Nanofibers were applied to the polypropylene side of the two
layer cellulosic/polypropylene material. The wipe was tested by its
use in an automobile and was wiped on a vehicle dash.
[0052] In FIG. 1, at .times.200 magnification, we see dirt,
particulate 10 sized as 50-70 .mu.m, with many much smaller
particulate in the nanofiber web 11. Fabric substrate 12 is shown
in the background. Much of the nanofiber web 11 is discontinuous
and dirt covered. In FIG. 2, at .times.1500 magnification, we see
soil particles 20 and nanofiber 21 wound and bound together with
substrate fabric fiber 23 in background. Some portion of the
particles is held in nanofiber/particulate bundle 24. Other
particulate 25 is adhered to the surface of the nanofibers,
presumably through Van der Waal's forces. In FIG. 3, at .times.5000
magnification, we can see dirt particulate 30 bundled in the
discontinuous nanofiber web 31. In FIG. 1, at .times.200
magnification again, in places where the nanofiber web is gone,
dirt is migrated into the depth of the substrate past the nanofiber
layer where particulate wedges between fibers. Small particles are
clearly preferentially retained by nanofiber versus larger
particulate in larger fibers. In FIG. 4, at .times.10,000
magnification, dirt particulate 40 is shown wound up in nanofiber
41. We see particles 42 about 0.2 .mu.m in size.
Automotive Window Testing
FIGS. 5-7
[0053] Sample is nanofibers applied to the polypropylene side of
the two layer non-woven, wiped on vehicle interior window.
[0054] In FIG. 5, at .times.200 magnification, we see much less
dust and dirt 52, than FIGS. 1-4, most of the nanofiber web 50 is
still substantially intact due reduced abrasion from particulate
from a cleaner surface. Fabric substrate fiber 51 is in background.
In FIG. 6, at .times.2500 magnification, we see an area of
rolled-up nanofiber 60 adjacent to nanofiber web 62, with a coating
of agglomerated substantially organic soil or contaminant 61 on the
nanofiber. The window soil is not largely inorganic particulate,
but is greasy, organic matter that coats the fiber as compared to
the dry particulate on the dash that is enmeshed by or entangled in
the nanofiber. The organic soil is easily picked up by the
nanofiber web, which provides a substantial of surface area contact
and a compatible surface. In FIG. 7, at .times.10000 magnification,
we see a close-up picture of the organic soil 61 coating the fiber
with adjacent nanofiber 70 and web 71.
Automotive Window Testing
FIGS. 8-11
[0055] In FIG. 8 at .times.200 magnification, we see most of the
web structure 80 intact, with little particulate 81 or
contaminant.
[0056] In FIG. 9 at .times.1000 magnification, we see some
contaminant particles 90 on the web 91, some on the fiber of
substrate surface 92. We can also see areas where nanofiber web is
discontinuous. The large substrate fiber 92 without a nanofiber
covering suggests that it has moved from its original location,
driving, wiping. There is also evidence of organic contaminant 93
collected on the nanofiber web portion bonded to the substrate
fibers. In FIG. 10 at .times.4000 magnification, we see organic
contaminant 100 on nanofibers 101, as well as some particulate 102
that has been captured/wedged behind the nanofiber structure. In
FIG. 11 at .times.17000 magnification, we see the captured/wedged
particle 102 behind nanofiber 110. We can discern contaminants as
small as 0.05-0.1 .mu.m. There is also a coiled-up section of
nanofibers agglomerated with particles and organic soil 111 bundled
in a fiber web.
Automotive Dash Testing
FIGS. 12-14
[0057] Sample is nanofibers on pulp side wiped on dash.
[0058] FIG. 12 at .times.200 magnification, we see that more of the
nanofiber web is intact than samples in FIGS. 1-4. There is a lot
of particulate 120, some areas of exposed substrate fiber 121 and
discontinuous nanofiber web 122. FIG. 13 at .times.1000
magnification, we see that many particles 130 are collected on the
nanofiber web surface 131, but that some particles 132 have been
captured between the nanofiber layer and the substrate fibers or in
the fabric. Particulate can move into the depth through nanofiber
web hole and migrate behind. FIG. 14 at .times.4000 magnification,
we see a close-up of the particle 132 behind the web 140, with
other particulate 141 on top. Particulate 142, as small as 0.5
.mu.m, can be seen held or entangled in the fiber. FIG. 13 at
.times.1000 magnification again, we see a particle underneath the
nanofiber web, as far as 50 .mu.m away from a hole large enough to
allow its passage.
Automotive Dash Testing
FIGS. 15-17
[0059] Sample is nanofibers applied to pulp side, wiped across
dash.
[0060] In FIG. 15 at .times.200 magnification, we see most of
nanofiber web 150 intact with some holes 151 and discontinuous
areas. In FIG. 16 at .times.1500 magnification, we see a few
particles 160 wrapped up in nanofibers 161. We see a large (20-30
.mu.m) particle 162 sitting on top of the nanofiber web. We see a
large substrate fiber 163 that has captured few a particles 164 on
its surface. In FIG. 17 at .times.6000 magnification, we see a
close-up of the captured particles 160 and the nanofiber web 161.
In FIG. 16 at .times.1500 magnification again, we see a particle
lodged underneath the nanofiber web. This particle is perhaps 30
.mu.m away from the nearest web discontinuity that is sufficiently
sized to allow its passage.
[0061] In previously filed applications, the formation of fine
fiber layers on filtration media has been disclosed. Such filter
structures are different than a wipe structure. In order to
establish a clear distinction between a wipe material and a
filtration structure, a number of consumer wipe materials were
purchased and tested for stiffness characteristics. Filtration
media must have characteristic stiffness to operate in the
filtration environment in which a stream of liquid or gas passes
through the filter and particulate is removed. The media must be
stiff enough to survive the mechanical stress placed on the filter
media by the moving fluid. Both dry and wet wipes were tested. Wet
wipes were washed and dried before testing for stiffness.
[0062] Wipes substrates tested--wet (all were soaked in filtered
deionized water at room temperature for 10 minutes, with three
water change-out, then dried in an oven at 85.degree. C. for 10
minutes). Rain-X Glass cleaner with Anti-Fog Wipes--Rain-X; Rain-X
Wipes; Wet Ones Antibacterial Wipes--Playtex Products Inc. Pledge
Wipes--S.C. Johnson & Son, Inc. Clorox Disinfecting Wipes--The
Clorox Company Windex Glass and Surface Wipes--S.C. Johnson &
Son, Inc. Clean & Clear Deep Action Cleansing Wipes_Johnson
& Johnson Pond's Cleansing and Make-Up Remover
Towelettes--Chesebrough-Pond's USA Co. Wipes materials tested--dry
Swiffer disposable cloths--Proctor & Gamble Pledge Grab-It dry
cloths--S.C. Johnson & Son, Inc. Each sample was tested for
stiffness according to TAPPI T-543 om-00: "Bending Resistance of
Paper (Gurley-Type Tester)". In performing the test, a bending
resistance/stiffness test instrument is used that consists of a
balanced pendulum or pointer which is center-pivoted and can be
weighted at three points below its center. The pointer moves freely
in both left and right directions on cylindrical jewel bearings
which make the mechanism highly sensitive even to light-weighted
materials.
[0063] A sample of a specific size is attached to a clamp, which in
turn is located on a motorized arm, which also moves left and
right. The bottom 0.25 inch of the sample overlaps the top of the
pointer (a triangular shaped "vane"). During the test the sample is
moved against the top edge of the vane, moving the pendulum until
the sample bends and releases it.
[0064] On digital models, the point of release is automatically
measured by an optical encoder and displayed on a digital readout.
this readout continuously displays readings from tests performed in
both the left and right directions. In addition, the on-board
microprocessor automatically computes and displays the average of
left and right stiffness data after each measurement is performed.
For flat sheet materials, the operator can then press a button to
automatically convert the point-of-release reading on the display
to force (milligrams).
[0065] However, none of the material samples had sufficient
stiffness to be measured using this method. The minimum stiffness
value that can be accurately measured on this Gurley stiffness
tester is approximately 300 mg. As such, the stiffness of each of
these materials is known to be less than 300 mg. Typical stiffness
values for other filter media types are about 350-12,000 mg.
[0066] The foregoing constitutes a complete description of the
embodiments of the invention recognized to date. However, since the
invention can reside in a variety of embodiments without departing
from the spirit and scope of the invention, the invention resides
in the claims hereinafter appended.
* * * * *