Note: Descriptions are shown in the official language in which they were submitted.
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LAYERED CLEANING SHEETS
Field Of The Invention
4 The present invention relates generally to cleaning materials and more
particularly to
layered cleaning sheets having a layer of electret material and a layer of
absorbent material.
Background And Summary Of The Invention
8 The advent of cleaning materials, such as cleaning sheets, cloths, towels,
wipes and
the like, has greatly aided in the ability of consumers to clean up and remove
particulate and
liquid materials from various surfaces.
However, conventional cleaning materials, such as electrostatically charged
materials
12 or adhesive-containing materials (e.g., wipes, lint brushes, feather
dusters, adhesive rollers,
and the like), are typically only suitable for picking up particulate
materials, such as dust,
lint, hair, soil and the like, and are generally unsuitable for cleaning and
removing liquid
materials due, in part, to their inability to absorb sufficient amounts of the
liquid materials.
16 Thus, these cleaning materials can only be effectively used when the
material to be removed
is completely, or at least substantially, comprised of particulate material
(i.e., there is very
little or no liquid present in or near the particulate material to be
removed).
Conversely, other conventional cleaning materials, such as highly absorbent
cloth
2 0 and fibrous materials (e.g. paper towels, cloth towels, and the like), are
particularly well-
suited for picking up liquid materials, such as water. However, they are
generally unsuitable
for cleaning and removing particulate materials due, in part, to their
inability to attract and
retain the particulate materials. Thus, these materials can only be
effectively used when the
2 4 material to be removed is completely, or at least substantially, comprised
of liquid material
(i.e., there is very little or no particulate material present in or near the
liquid material to be
removed). Additionally, these highly absorbent cloth and fibrous materials
tend to allow the
liquid materials to penetrate completely through the material, thus causing
the user's hand to
2 8 become soiled by the liquid material that is being removed. This situation
is especially
unsatisfactory if the liquid material has an obj ectionable odor or contains
pathogenic
material.
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As a result, the consumer must purchase and store both types of conventional
cleaning materials in order to deal with any future cleaning needs, whether
they be for liquid
or particulate materials.
4 Therefore, there exists a need for a cleaning sheet that is capable of
cleaning
particulate materials and liquid materials equally well, while protecting the
user's hand from
becoming soiled when cleaning liquid materials.
In accordance with one embodiment of the present invention, a cleaning sheet
for
8 cleaning and removing particulate materials and liquid materials from a
surface is provided,
comprising a layer of electret material, and a layer of absorbent material
adjacent to the layer
of electret material.
In accordance with another embodiment of the present invention, a cleaning
sheet for
12 cleaning and removing particulate materials and liquid materials from a
surface is provided,
comprising a layer of electret material, a layer of absorbent material
adjacent to the layer of
electret material, and a layer of adhesive material disposed between the layer
of electret
material and the layer of absorbent material.
16 In accordance with still another embodiment of the present invention, a
cleaning
sheet for cleaning and removing particulate materials and liquid materials
from a surface is
provided, comprising a layer of electret material, a layer of absorbent
material adjacent to the
layer of electret material, and a layer of barrier material disposed between
the layer of
2 0 electret material and the layer of absorbent material.
In accordance with still another embodiment of the present invention, a
cleaning
sheet for cleaning and removing particulate materials and liquid materials
from a surface is
provided, comprising a layer of electret material, a layer of absorbent
material adjacent to the
2 4 layer of electret material, a layer of barrier material disposed between
the layer of electret
material and the layer of absorbent material, a layer of adhesive material
disposed between
the layer of electret material and the layer of barrier material, and a layer
of adhesive material
disposed between the layer of barrier material and the layer of absorbent
material.
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Brief Description Of The Drawings
The present invention will become more fully understood from the detailed
description and the accompanying drawings, wherein:
4 Figure 1 is a perspective view of a dual layer cleaning sheet, in accordance
with one
embodiment of the present invention;
Figure 2 is a cross-sectional view of the dual layer cleaning sheet depicted
in Figure
1;
8 Figure 3 is a perspective view of a multi-layer cleaning sheet, in
accordance with a
first alternative embodiment of the present invention;
Figure 4 is a cross-sectional view of the mufti-layer cleaning sheet depicted
in Figure
3;
12 Figure 5 is a perspective view of a mufti-layer cleaning sheet, in
accordance with a
second alternative embodiment of the present invention; and
Figure 6 is a cross-sectional view of the mufti-layer cleaning sheet depicted
in Figure
5.
16 The same reference numerals refer to the same parts throughout the various
Figures.
Detailed Description Of The Preferred Embodiments
The layered cleaning sheets of the present invention are particularly suitable
for
2 0 cleaning and removing particulate material (e.g., dust, hair, lint, soil,
and the like) as well as
liquid material (e.g., water, and the like). The layered cleaning sheets of
the present
invention are preferably used on substantially hard or rigid surfaces (e.g.,
tables, shelving,
floors, ceilings, hard furnishings, household appliances, and the like);
however, it should be
2 4 appreciated that the layered cleaning sheets of the present invention may
be used on
relatively softer surfaces as well (e.g., rugs, carpets, soft furnishings,
linens, clothing, and the
like). The layered cleaning sheets of the present invention can be washed,
dried, and re-used
over and over again over an extended period of time without any substantial
diminishment of
2 8 their cleaning properties, tearing, pilling, or changes in dimensional
stability.
With reference to Figures 1 and 2, a dual layer cleaning sheet 10, in
accordance with
one embodiment of the present invention, is comprised primarily of a first
layer 12 of electret
material and a second layer 14 of absorbent material. The designation of
"first" and "second"
3 2 layers are used for reference purposes only and is not meant to limit the
scope of the present
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invention. The exact dimensions of the cleaning sheet 10 are not thought to be
critical to the
success of the present invention; thus, the cleaning sheet 10 can be
configured in a variety of
shapes.
4 The first layer 12 may be fastened, attached, or otherwise secured to the
second layer
14 by any number of conventional methods, such as, but not limited to
stitching (e.g., along
the periphery, or alternatively, at predetermined points so as to form a
"checkerboard",
"cross", "crisscross", or any other desired pattern). The exact manner in
which the first layer
8 12 is fastened, attached, or otherwise secured to the second layer 14 is not
thought to be
critical provided that the two respective layers do not separate from one
another, for
example, during routine use.
The electret material is primarily intended to be used for the cleaning and
removal of
12 particulate material, whereas the absorbent material is primarily intended
to be used for the
cleaning and removal of liquid material. As will be described herein, the
particular features
of the materials comprising each of the two layers make them particularly
suitable for their
intended uses.
16 The first layer 12 is preferably comprised of a plurality of fibers. The
fibers can be
comprised of synthetic materials, such as, but not limited to, thermoplastics.
The
thermoplastics can include, without limitation, polypropylene, polyethylene,
polyester,
nylon, rayon, and acrylic.
2 0 The physical dimensions of the first layer 12 are not thought to be
critical; however,
the first layer 12 is preferably a relatively thin (as compared to the second
layer 14), single
planar sheet of woven electret fibers. Preferably, the first layer 12 has a
shape and
configuration similar to that of the second layer 14. It is believed that the
fiber thickness and
2 4 length are not critical to the success of the present invention provided
that the resulting first
layer 12 is sufficiently thin and flexible to clean and remove particulate
material. Preferably,
the denier values (i.e., the weight of 9000 meters of a single filament fiber)
of the fibers of
the first layer 12 are in the range of about 0.5 to about 4. Preferably, the
thickness values of
2 8 the fibers of the first layer 12 are in the range of about 0.05 to about
0.2 inches, with about
0.05 to about 0.1 inches being highly preferred. Preferably, the density of
the fibers of the
first layer 12 is such that there are no voids greater than 100 microns wide,
and more
preferably, no greater than 20 microns wide.
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The first layer 12 can be constructed by any number of conventional methods,
including, but not limited to, wet laid, dry laid, hydroentangled, spun-bound,
needle punches,
and the like.
4 The thermoplastic materials are preferably suitable for the generation of a
permanent
electrostatic charge on the surface of the fibers. These permanently
electrostatically charged
materials are generally referred to as electret materials. A discussion of
electret materials,
and methods of producing the same, can be found in U.S. Patent Nos. 3,998,916
issued to
8 van Turnhout; 4,178,157 issued to van Turnhout et al.; 4,215,682 issued to
Kubik et al.;
4,308,223 issued to Stern; 4,375,718 issued to Wadsworth et al.; 4,486,365
issued to
Kliemann et al.; 4,789,504 issued to Ohmori et al.; and 5,726,107 issued to
Dahringer et al.,
the specifications of all of which are expressly incorporated herein by
reference.
12 An electret material, also generally referred to as an electret, is a
dielectric material
which retains an electrostatic charge for many years and as such can be
considered the
electrostatic equivalent of a permanent magnet. Thus, while the magnet is a
permanent
source of external magnetic field, the electret is a permanent source of
electric field.
16 Electrets are usually produced in sheet or film form with one surface
positively charged and
the other surface negatively charged.
When an electret is formed, the material is said to be polarized; i.e., the
charges have
been oriented in a preferred direction. This polarization can involve either
heterocharges,
2 0 homocharges, or both, depending on the material used and the method of
preparation.
When the charges are arranged in positive-negative pairs and aligned in the
same
direction throughout the material it is said to be heterocharged. When
individual charges
collect on the surface of the electret material it is said to be homocharged.
Here, charges of
2 4 the same kind are fixed in one surface with the opposite charges on the
other surface.
Recently, interest has centered on the production of homocharged-only
electrets,
where in essence the effect is simply the ability of some materials to retain
surface
electrostatic charge for considerable periods of time. This interest coincided
with the advent
2 8 of thermoplastics in flexible film form. These thermoplastics retain
charge for ling periods
of time and because of their very good insulating properties and roll film
form, permit
simpler continuous charging techniques. Electrets of this type have been made
from
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polyethylene, polypropylene, polystyrene, polycarbonate, and many other types
of
thermoplastics. The electrets of the present invention are preferably
homocharged-only
electrets.
4 In operation, the electret materials of the present invention have
demonstrated good
dry dust and particulate soil removal from hard surfaces in comparison to
conventional fabric
or fibrous cleaning materials. This is due to the fact that the electret
materials actively attract
particulate material during the cleaning process, as opposed to conventional
cloth or fibrous
8 cleaning materials which merely physically contact the particulate material,
with the
particulate material adhering to, or being enveloped by, the conventional
cloth or fibrous
cleaning material.
To illustrate the attractive features of the electret material comprising the
first layer
12 12 of the cleaning sheet 10, a comparative test was conducted among a
conventional cotton
cleaning cloth (e.g., 100% flannel cloths) obtained from Darra (North
Hollywood,
California), a conventional generic brand polyester cleaning cloth, and a
cleaning cloth (sold
under the tradename ECM-85 PFP) comprised of a single layer of electret fibers
obtained
16 from All Felt (Ingleside, Illinois). The comparative testing procedure is
presented in
Example I, below:
Example I
2 0 A standard dust cabinet was provided having a total internal volume of
0.468
cubic meters. A 241 centimeter x 127 centimeter section of furniture surface
(oak with high gloss nitrocellulose lacquer) was cleaned to remove any dust,
polish, fingerprints and was placed inside the cabinet. After the cabinet was
24 sealed, and thirty minutes before the testing procedure was commenced, 10
grams of a 50:50 weight ratio mixture of particulate matter comprised of
sieved (100 micron) vacuum cleaner dust (i.e., dust) and Bandy Black
research clay (i.e., dirt) (Textile Innovators Corp., Windsor, North Carolina)
2 8 was introduced into the cabinet by a Vent-Axia TX7IL fan unit having a
maximum flow rate of 645 cubic meters/hour. A$er 2 minutes of circulation,
the fan unit was stopped and the particulate matter was allowed to settle for
one hour. Several samples of each type of cleaning cloth were prepared into
32 21.~ centimeter x 12.5 centimeter strips. A PLEDGE GRAB-ITTT'' sweeper
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unit with a base footprint of 10 centimeters x 25.5 centimeters was divided
using a marker pen into two sections, both 10 centimeters x 12.5 centimeters,
i.e., the base of the sweeper unit was divided into two sections, each of
which
4 had a corresponding pair of fabric grips on the upper surface of the sweeper
unit. For cloths designed to be used in a particular direction (i.e., the
direction of stroke of the sweeper unit) the longer dimension was taken to the
direction of the stroke. Each test cloth was weighed and then inserted on one
8 side of the sweeper unit so that two cloths under test would just touch in
the
middle and cover the full extent of the sweeper unit. For convenience, the
handle attached to the sweeper unit was shortened to approximately 30
centimeters long. The cabinet was opened and the sweeper unit/cloth
12 assembly was wiped over the furniture surface (three lateral sweeps so that
each cloth covers three areas of dusted surface 127 centimeters long). With
care not to dislodge any particulate matter, the cloths were removed and re-
weighed. Each cloth was then given a firm shake and then re-weighed to
16 determine the amount of particulate matter retained by the cloth. The
results
of this testing procedure are presented in Table I.
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Table I
Product Cloth MassCloth and ParticulatePost- Residual
Type and (grams) ParticulateMaterial Shaking Particulate
Sample Material Mass Cloth and Material
Number Mass (grams) ParticulateMass
(grams) Material (grams)
Mass
(grams)
Cotton 3.98 4.18 0.20 4.06 0.08
Duster
# 1
Cotton 3.99 4.19 0.20 4.03 0.04
Duster
#2
Cotton 3.98 4.18 0.20 4.03 0.05
Duster
#3
Cotton 4.00 4.22 0.22 4.04 0.04
Duster
#4
Cotton 3.99 4.22 0.23 4.04 0.05
Duster
#5
Cotton 3.98 4.18 0.20 4.04 0.06
Duster
#6
Cotton 3.99 4.18 0.19 4.04 0.05
Duster
#7
Cotton 4.00 4.22 0.22 4.04 0.04
Duster
#8
Cotton 3.98 4.17 0.19 4.02 0.04
Duster
#9
Cotton 3.99 4.18 0.19 4.04 0.05
Duster
#10
Average 3.99 4.19 0.20 4.04 0.05
Polyester 1.42 1.60 0.18 1.52 0.10
cloth #1
Polyester 1.41 1.59 0.18 1.51 0.10
cloth #2
Polyester 1.40 1.59 0.19 1.49 0.09
cloth #3
Polyester 1.41 1.59 0.18 1.51 0.10
cloth #4
Polyester 1.39 1.57 0.18 1.49 0.10
cloth #5
Polyester 1.41 1.58 0.18 1.51 0.10
cloth #6
Polyester 1.42 1.61 0.19 1.53 0.11
cloth #7
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Table 1 continued
Product Cloth MassCloth and ParticulatePost- Residual
Type and (grams) ParticulateMaterial Shaking Particulate
Sample Material Mass Cloth and Material
Number Mass (grams) ParticulateMass
(grams) Material (grams)
Mass
(grams)
Polyester 1.41 1.58 0.17 1.50 0.09
cloth #8
Average 1.41 1.59 0.18 1.51 0.10
Electret 2.01 2.31 0.30 2.21 0.20
cloth #1
Electret 2.00 2.31 0.31 2.20 0.20
cloth #2
Electret 2.02 2.33 0.31 2.23 0.21
cloth #3
Electret 2.02 2.31 0.29 2.20 0.18
cloth #4
Electret 2.00 2.30 0.30 2.19 0.19
cloth #5
Electret 2.01 2.30 0.29 2.21 0.20
cloth #6
Electret 2.00 2.30 0.30 2.19 0.19
cloth #7
Electret 2.01 2.30 0.29 2.20 0.19
cloth #8
Average 2.01 2.31 0.30 2.20 0.20
As the results in Table I indicate, the cleaning cloth having a layer
comprised of
4 electret fibers, in accordance with the present invention, not only
attracted more particulate
matter than the other types of cleaning cloths, but also retained more
particulate matter after
being shaken.
The chemical (e.g., thermoplastic) and physical (e.g., hydrophobic) nature of
the
8 electret materials of the present invention necessarily means that they have
relatively low
liquid absorbency. Accordingly, a benefit of this relatively low level of
liquid absorbency is
that the electret material of the first layer 12 functions as a semi-
impervious barner to the
liquid materials, i.e., the electret material of the first layer 12 is at
least partially impervious
12 to the liquid materials. Thus, when the second layer 14 of the cleaning
sheet 10 is being used
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for cleaning and/or removal of liquid material, the first layer 12 functions
to prevent any
substantial amount of the liquid material from passing through the first layer
12 and soiling
the user's hand. This feature is especially beneficial if the liquid material
has an
4 objectionable odor or contains pathogenic material.
To illustrate the imperviousness features of the material comprising the first
layer 12
of the cleaning sheet 10, a comparative test was conducted among a
conventional wool
cleaning cloth, a conventional cotton cleaning cloth (e.g., a duster), a
conventional cellulosic
8 cleaning cloth (e.g., a paper towel), and cleaning cloths comprised of non-
electret synthetic
fibers such as rayon, polyester, polypropylene, and nylon. The comparative
testing
procedure is presented in Example II, below:
12 Example II
Laminate cloths were constructed using, on the lower layer, a super-absorbent
material comprising 30 weight percent Oasis FSA (Technical Absorbents,
Ltd.), SO weight percent Fluff PLP, and 20 weight percent thermal bondable
16 fiber. The upper layer, which was non-electret, comprised a fabric under
test
for water strike-through. The cloths were cut to 7.6 centimeter x 7.6
centimeter squares and stitched together at the edges only. One hundred ml
of water was placed on a horizontal surface so that it formed a puddle. The
2 0 cloth laminate was placed in the middle of the puddle, super-absorbent
layer
down so that the super-absorbent layer became saturated. The cloth laminate
was left in contact with the water for 5 minutes. The cloth laminate was then
placed on a separate surface and left for a further 5 minutes. The upper layer
24 of the laminate cloth was gently touched with a finger and rated for
dampness
(i.e., initial dampness) on a ten-point scale, with 0 indicating no dampness
and 10 indicating saturation. Once rated, the pad was pressed with three
fingers and re-rated for the amount of dampness (i.e., final dampness) that
2 8 was felt after the application of pressure. The results of this testing
procedure
are presented in Table II.
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Table IITable IITable II
Cloth Material Type Initial Dampness Final Dampness
Wool 2 5
Cotton 3 6
Cellulose 6 9
Rayon 1 2
Polyester 0 1
Polypropylene 0 0
Nylon 0 1
As the results in Table II indicate, the cleaning cloth having a layer
comprised of
4 synthetic fibers (e.g., rayon, polyester, polypropylene, and nylon), in
accordance with the
present invention, did not allow a significant amount of water to penetrate
therethrough, and
in fact, the polypropylene material did not allow any water penetration (i.e.,
strike-through)
whatsoever.
8 The second layer 14 is preferably comprised of an absorbent material, and
still more
preferably a super-absorbent material, that is capable of absorbing relatively
large amount of
liquid materials, especially water. A super-absorbent material is generally
defined as a
water-insoluble, water-swellable polymer material capable of absorbing water
in an amount
12 which is at least ten times the weight of the substance in its dry form.
Additionally, super-
absorbents also retain the absorbed liquid far better than conventional
materials. Thus, once
the liquid is absorbed by the super-absorbent material, it is difficult for
the liquid to be
released from the super-absorbent material.
16 Preferably, the super-absorbent material is formed into a plurality of
fibers which are
then formed into the second layer 14. The super-absorbent fibers of the
present invention are
preferably absorbent of any liquid material, more preferably absorbent of any
aqueous-based
liquid material, and still more preferably absorbent of water.
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A discussion of absorbent materials, including apparatuses and methods for
producing the same, can be found in U.S. Patent Nos. 3,814,101 issued to
Kozak; 3,886,941
issued to Duane et al.; 3,987,792 issued to Hernandez et al.; 4,062,817 issued
to Westerman;
4 4,232,128 issued to Michel et al.; 4,328,279 issued to Meitner et al.;
4,360,015 issued to
Mayer; 4,540,454 issued to Pieniak et al.; 4,606,958 issued to Haq et al.;
4,659,609 issued to
Lamers et al.; 4,977,892 issued to Ewall; 5,591,155 issued to Nishikawa et
al.; 5,658,268
issued to Johns et al.; 5,658,269 issued to Osborn et al.; 5,658,270 issued to
Lichstein;
8 5,704,928 issued to Morita et al.; 5,704,929 issued to Bein; 5,704,930
issued to Lavash et al.;
5,704,931 issued to Holtman et al.; 5,704,932 issued to Hibbard; 5,705,249
issued to Takai
et al.; 5,713,884 issued to Osbom et al.; 5,728,082 issued to Gustafsson et
al.; 5,728,084
issued to Palumbro et al.; 5,713,855 issued to Jorgenson et al.; 5,713,881
issued to Rezai et
12 al.; 5,713,883 issued to Hsieh; 5,713,886 issued to Sturino; 5,725,518
issued to Coates;
5,728,085 issued to Widlund et al.; 5,728,081 issued to Baer et al.; 5,766,212
issued to Jitoe
et al.; 5,766,213 issued to Hackman et al.; 5,772,649 issued to Siudzinski;
5,772,650 issued
to Mizutani; 5,779,689 issued to Pfeifer et al.; 5,779,690 issued to
Gustafsson et al.;
16 5,779,691 issued to Schmitt; 5,779,692 issued to Lavash et al.; 5,785,696
issued to moue et
al.; 5,785,697 issued to Trombetta et al.; 5,785,698 issued to Van Item;
5,785,699 issued to
Schmitz; 5,786,056 issued to Komine et al.; 5,792,129 issued to Johansson et
al.; 5,792,131
issued to Mizutani; 5,792,132 issued to Garcia; 5,795,345 issued to Mizutani
et al.;
2 0 5,795,346 issued to Achter et al.; 5,795,347 issued to Roe et al.;
5,795,349 issued to Lavash
et al.; 5,797,894 issued to Cadieux et al.; 5,800,416 issued to Seger et al.;
5,800,417 issued to
Gogerg-Wood et al.; 5,800,418 issued to Ahr; 5,800,419 issued to Soga et al.;
5,803,920
issued to Gilman; 5,810,796 issued to Kimura et al.; 5,810,797 issued to
Menard et al.;
24 5,810,798 issued to Finch et al.; 5,810,799 issued to Slater; 5,810,800
issued to Hunter et al.;
5,814,034 issued to Widlund et al.; 5,814,035 issued to Gryskiewicz et al.;
5,814,036 issued
to Ronnberg et al.; 5,814,037 issued to Coates; 5,817,076 issued to Fard;
5,817,077 issued to
Foley et al.; 5,817,079 issued to Bergquist et al.; 5,817,394 issued to
Alikhan et al.;
2 8 5,817,400 issued to Chen et al.; 5,820,615 issued to Koczab; 5,820,619
issued to Chen;
5,855,573 issued to Johansson; 5,858,011 issued to Brown et al.; 5,858,012
issued to
Yamaki et al.; 5,858,013 issued to Kling; and 5,916,507 issued to Dabi et al.,
the
specifications of all of which are expressly incorporated herein by reference.
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The second layer 14 is preferably comprised a plurality of polymeric fibers
(e.g.,
thermoplastics) comprised of up to about 70 weight percent of a cross-linked
acrylate
copolymer (preferably partially neutralized to the sodium salt) that acts as a
water super-
4 absorbent. Super-absorbent materials, in accordance with the present
invention, are readily
commercially available under the tradenames LANSEAL F~'~"'' (Toyobo Company,
Limited,
Osaka, Japan), FIBERSORB~ (DuPont, Wilmington, Delaware), and OASIS (Technical
Absorbents Limited, Grimsby, England).
8 The super-absorbent fibers of the present invention have been demonstrated
to absorb
and retain up to about eighty times their own weight of water, whereas
conventional natural
fibers, such as cotton, wool, cellulose, and even synthetic fibers, such as
nylon,
polypropylene, and rayon, absorb only around up to about seven times their own
weight. To
12 illustrate the differences in absorptive capacity a comparative test was
conducted among the
various materials and the super-absorbent material of the present
invention. The comparative testing procedure is presented in Example III,
below:
16 Example III
Weighed amounts of fabric samples of known fiber composition were placed
into a beaker containing an excessive amount of water and left for 10
minutes. The fabric samples were then removed and allowed to drip dry for
2 0 30 seconds and then re-weighed to determine the amount of water retained.
The results of the testing procedure are presented in Table III.
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Table IIITable IIITable III
Fabric FiberInitial MassInitial MassMass of the Weight
of of
Type the Fabric the Fabric Water Percentage
and of
(grams) Retained Retained the Water
Water (grams)(grams) Retained
(grams)
OASISTM 5.0 389.0 384.0 7680% (i.e.,
super- 76.8 times
the
absorbent initial mass)
Cotton 5.0 40.8 35.8 716% (i.e.,
7.16 times
the
initial mass)
Wool 5.0 38.6 33.6 672% (i.e.,
6.72 times
the
initial mass)
Cellulose 5.0 31.8 26.8 536% (i.e.,
(paper towel) 5.36 times
the
initial mass)
Rayon S.0 5.3 0.3 6% (i.e.,
0.06
times the
initial mass)
Nylon 5.0 S.1 0.1 2% (i.e.,
0.02
times the
initial mass)
Poly- 5.0 5.1 0.1 2% (i.e.,
0.02
propylene times the
initial mass)
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As the results in Table III indicate, the fabrics comprised of natural fibers
retain only
about 5.36 to 7.16 times their initial mass of water. The fabrics comprised of
synthetic fibers
4 retain only about 0.02 to 0.06 times their initial mass of water.
Conversely, the fabric
comprised of super-absorbent material, in accordance with the present
invention, retains
nearly 80 times its own weight in water.
The advantage of employing super-absorbent fibers is two-fold. First, the
fibers
8 permit the quick absorption of liquid materials (e.g., spills) far more
efficiently than
conventional paper towels or cloth towels. Second, when used in conjunction
with an
aqueous-based cleaner (e.g., a surfactant), the fibers improve the efficiency
of the cleaner, as
well as particulate removal from a surface, which is especially important on
surfaces that can
12 be damaged by moisture.
The second layer 14 optionally contains other natural or synthetic fibers to
increase
tensile strength of this layer, such as, but not limited to wool, cotton,
cellulose,
polypropylene, polyethylene, polyester, nylon, rayon, and acrylic.
16 The physical dimensions of the second layer 14 are not thought to be
critical;
however, the second layer 14 is preferably a relatively thick (as compared to
the first layer
12), single planar sheet of non-woven absorbent fibers. By way of a non-
limiting example,
the second layer 14 can be up to about 0.25 inches in diameter. Preferably,
the second layer
2 0 14 has a shape and configuration similar to that of the first layer 12.
With reference to Figures 3 and 4, a mufti-layer cleaning sheet 30, in
accordance with
a first alternative embodiment of the present invention, is comprised
primarily of a first layer
32 of electret material (as previously described), a second layer 34 of
absorbent material (as
24 previously described), and a third layer 36 of adhesive material disposed
between the first
layer 32 and the second layer 34. The designation of "first", "second", and
"third" layers is
for reference purposes only and is not meant to limit the scope of the present
invention.
The third layer 36 of adhesive material may be applied to any suitable surface
of
2 8 either, or both, the first layer 32 and/or the second layer 34. By way of
a non-limiting
example, the adhesive material may be applied as a solid layer, a continuous
pattern (e.g., a
circle or serpentine pattern), a discontinuous pattern (e.g., a series of
lines or a matrix of
dots), or any other desired pattern.
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The third layer 36 of adhesive material is intended to function as a way to
bond
(physically and/or chemically), fasten, attach, or otherwise secure the first
layer 32 to the
second layer 34. Additionally, the third layer 36 of adhesive material is
intended to function
4 as an impervious, or at least a semi-impervious, barrier against liquid
materials penetrating
through to the first layer 32, i.e., the adhesive material of the third layer
36 is at least partially
impervious to the liquid materials. Preferably, the adhesive material is water-
proof and
otherwise impervious to liquid materials. By way of a non-limiting example,
the semi-
8 impervious nature of the first layer 32 can be enhanced or reinforced by
employing a solid
layer of water-proof, and preferably liquid impervious, adhesive material.
Furthermore, the
third layer 36 of adhesive material also adds strength and durability to the
cleaning sheet 30.
The multi-layer cleaning sheet 30 is intended to function in the same manner
as the
12 dual-layer cleaning sheet 10, i.e., the first layer 32 of electret material
is primarily intended to
clean and remove particulate material, whereas the second layer 34 of
absorbent material is
primarily intended to clean and remove liquid material.
With reference to Figures 5 and 6, a mufti-layer cleaning sheet 50, in
accordance with
16 a second alternative embodiment of the present invention, is comprised
primarily of a first
layer 52 of electret material (as previously described), a second layer 54 of
absorbent
material (as previously described), a third layer 56 of burner material
disposed between the
first layer 52 and the second layer 54, an optional fourth layer 58 of
adhesive material
2 0 disposed between the first layer 52 and the third layer 56, and an
optional fifth layer of
adhesive 60 disposed between the second layer 54 and the third layer 56. The
adhesive
layers 58 and 60, respectively, are described as being optional because the
third layer 56 of
burner material can be bonded (physically and/or chemically), fastened,
attached, or
2 4 otherwise secured to the first layer 52 and the second layer 54 without
resort to adhesives.
For example, the third layer 56 of burner material can be stitched to the
first layer 52 and the
second layer 54, or vice verse. The designation of "first", "second", "third",
"fourth", and
"fifth" layers is for reference purposes only and is not meant to limit the
scope of the present
2 8 invention.
In this embodiment, the third layer 56 of burner material is employed to
further
improve the imperviousness of the first layer 52 against the penetration of
liquid materials.
The burner material is preferably comprised of at least a partially or semi-
impervious
3 2 material, and still more preferably an impervious material, such as, but
not limited to,
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thermoplastics, especially those that are capable of being formed into films.
By way of a
non-limiting example, suitable materials include natural materials such as
rubber, latex, and
the like, as well as synthetic materials such polyvinyl chloride,
polyethylene, polyurethane,
and the like. The barrier material should preferably extend to, and along, the
periphery of
both the first layer 52 and the second layer 54 in order to provide a
continuous burner against
the penetration of liquid materials.
By way of a non-limiting example, the two adhesive layers 58 and 60,
respectively,
8 are provided in order to bond, fasten, attach, or otherwise secure the first
layer 52 and the
second layer 54 to the respective surfaces of the third layer 56 of barrier
material. One, or
both, of the adhesive layers 58 and 60 can be made impervious, or at least
partially or semi-
impervious, to liquid materials, thus fiu-ther enhancing the imperviousness of
the first layer
12 52 against the penetration of liquid materials. Furthermore, the third
layer 56 of barrier
material, as well as the fourth and fifth layers 58 and 60 of adhesive
material, also add
increased strength and durability to the cleaning sheet 50.
The mufti-layer cleaning sheet 50 is intended to function in the same manner
as the
16 previously described cleaning sheets 10 and 30, i.e., the first layer 52 of
electret material is
primarily intended to clean and remove particulate material, whereas the
second layer 54 of
absorbent material is primarily intended to clean and remove liquid material.
The foregoing description is considered illustrative only of the principles of
the
2 0 invention. Furthermore, because numerous modifications and changes will
readily occur to
those skilled in the art, it is not desired to limit the invention to the
exact construction and
process shown as described above. Accordingly, all suitable modifications and
equivalents
that may be resorted to that fall within the scope of the invention as defined
by the claims
2 4 that follow.
Industrial Applicability
The present invention is highly versatile as it may be utilized to clean both
substantially rigid surfaces such as countertops and floors as well as softer
surfaces like rugs
2 8 and carpeting. It can be manufactured with conventional manufacturing
equipment and
commercially available materials. Additionally, the cleaning sheets of the
present invention
may be washed and reused making them more environmentally sound than one-time
use
cleaning implements.
