Note: Descriptions are shown in the official language in which they were submitted.
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DISPERSIBLE NONWOVEN MATERIALS
Field of the Invention
The present invention generally relates to a fabric for various
uses, such as a garment, that can be disposed of using a liquid or
aqueous solution. More particularly, the present invention is directed
to a fabric having a hot water soluble component and a non-soluble
component that is dispersible.
Background of the Invention
Hospital patient care can generate considerable quantities of
infectious medical waste in primary and acute care facilities. One of
the substantial components of such medical waste is disposable
fabrics or garments. Typically, hospitals employ disposable garments
and other fabrics to prevent the spread of infection to hospital
workers and/or patients through the reuse of a fabric.
While such fabrics effectively inhibit infection, they must be
disposed of in some manner. One way that these fabrics can be
disposed is by using conventional solid waste management
techniques. For instance, it is estimated that disposable medical
fabrics comprise approximately one-half of infectious waste (0.5
million tons) generated by operating rooms each year. While this
type of infectious waste may only contribute a small percentage of the
total solid waste generated by hospitals yearly, the cost to dispose of
such waste (as well as other infectious waste types) can be
significantly greater than the costs of disposing of general waste.
As a result, disposable fabrics and garments have been
developed that can be disposed of in alternative ways. In particular,
fabrics were developed that would completely dissolve in hot water.
For example, one such fabric, which is described in U.S. Patent No.
5,207,837 to Hone~cutt, discloses a fabric made from polyvinyl
alcohol fibers that is completely soluble in water at certain
temperatures. This fabric can also be hydroentangled and/or
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thermally bonded. However, one of the problems of such completely
soluble fabrics is that they lack sufficient strength and dimensional
stability.
In addition to fabrics that are completely soluble in hot water,
other fabrics have been developed that are only partially soluble in
hot water. For example, one garment (OREXO), made by Isolyser
Company, Inc., can be partially dissolved in hot water. In particular,
this garment, which is described in more detail in U.S. Patent
5,268,222 to Honeycutt, contains a reusable component that is
substantially insoluble in aqueous solutions such that it can be
repeatedly relaundered and disinfected while a second component
within the garment dissolves when contacted with hot water and
washes down the drain. These fabrics can have increased strength
over completely soluble fabrics.
However, despite the benefits of such fabrics, a fabric having a
reusable component is not always desired. In many instances, for
example, a fabric is required that can be completely disposed of using
waste water disposal techniques, but that also has strength
characteristics of a fabric containing a reusable component. As such,
a need currently exists for a strong fabric that can be partially
dissolved in hot water and that does not have a reusable component
such that the entire fabric can be disposed of with waste water
treatment methods.
Summar~i of the Invention
The present invention recognizes and addresses the foregoing
disadvantages and drawbacks of prior art constructions. Objects and
additional advantages of the invention will be set forth in part in the
following description, or may be obvious from the description, or may
be learned through practice of the invention.
These and other objects of the present invention are achieved
by providing a fabric containing a hot water soluble component and a
dispersible component. In one embodiment, a fabric of the present
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invention includes non-soluble, but generally dispersible pulp fibers
and polyvinyl alcohol fibers that are soluble in hot water such that the
resulting fabric can be disposed of using waste water treatment
techniques, i.e. disposal of fabrics with hot water.
It should be noted that any given range presented herein is
intended to include any and all lesser included ranges. For example,
a range of from 45-90 would also include 50-90; 45-80; 46-89 and the
like. Thus, the range of 95% to 99.999% also includes, for example,
the ranges of 96% to 99.1 %, 96.3% to 99.7%, and 99.91 to 99.999%.
In accordance with the present invention, any material known
in the art to dissolve in aqueous solutions at high temperatures can
generally be used as a hot water soluble component of the present
invention. In particular, fibers that dissolve in aqueous solutions at
temperatures above about 37°C can generally be used as the hot
water soluble component of the present invention. In one
embodiment, fibers that dissolve in water at temperatures between
about 80°C and about 95°C are employed. For example, in one
embodiment of the present invention, polyvinyl alcohol fibers that
dissolve at the above temperature ranges are utilized as a hot water
soluble component of the present invention.
In addition to a hot water soluble component, a fabric of the
present invention also includes a dispersible non-soluble component.
In general, a dispersible component of the present invention can be
made from any material that is capable of dispersing in an aqueous
solution. For example, in one embodiment, the dispersible
component is made from pulp fibers either alone or in combination
with other fibers. It has been discovered that the addition of a
dispersible component, such as pulp fibers can provide strength and
dimensional stability to the fabric and can also allow the fabric to be
completely disposed of by waste water treatment techniques
In some applications, it is desired that the residue of the
dispersible component remaining after the fabric is contacted with hot
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water be minimized to ease in later waste water treatment. As such, a
dispersible component of the present invention, such as pulp fibers,
typically comprises less than about 55% by weight of the total content
of the fabric. In one embodiment, the dispersible component
comprises less than about 40%, and in particular, less than about 20%
of the total content of the fabric.
Besides the above-mentioned components, other materials
and/or chemicals can be generally added to a fabric of the present
invention. In particular, any material that does not affect the solubility
and/or dispersability of the fabric components can be added. For
example, dyes can be applied to the fabric to impart color. Moreover,
surface chemicals can be applied to impart water or alcohol repellancy
to the fabric surface.
In accordance with the present invention, the dispersible
component can also be entangled with the hot water soluble
component to further increase the strength of a fabric formed
therefrom. Any known method of entangling fibers, such as air
entangling or hydraulic (hydro) entangling, can be used. Hydraulic
entangling may be accomplished utilizing conventional hydraulic
entangling equipment such as may be found in, for example, in U.S.
Pat. Nos. 3,485,706 to Evans or 5,389,202 to Everhart et al., the
disclosures of which are hereby incorporated by reference. The
hydraulic entangling of the present invention may be carried out with
any appropriate working fluid such as, for example, water. The
working fluid flows through a manifold which evenly distributes the fluid
to a series of individual holes or orifices. These holes or orifices may
be from about 0.003 to about 0.015 inch in diameter. For example,
the invention may be practiced utilizing a manifold produced by
Honeycomb Systems Incorporated of Biddeford, Maine, containing a
strip having 0.007 inch diameter orifices, 30 holes per inch, and 1 row
of holes. Many other manifold configurations and combinations may
be used. For example, a single manifold may be used or several
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manifolds may be arranged in succession.
As such, in one embodiment of the present invention, the
dispersible component, e.g. pulp fibers, is hydraulically entangled into
a web of the hot water soluble component, e.g. polyvinyl alcohol fibers,
5 to form a fabric of the present invention. In another embodiment, each
component can be mixed with cold water to form a liquid suspension
of fibrous material which is thereafter formed into a web and
hydraulically entangled. Even if not specifically mentioned herein, any
other method of forming and/or entangling a fabric that is known in the
art can be used to produce a fabric of the present invention.
Generally, the hot water soluble and dispersible components
can also be formed into a multi-ply structure. In particular, a multi-
component structure of the present invention can have two or more
layers. For example, in one embodiment, the hot water soluble
component can be adhered to the dispersible component with a
dispersible adhesive. In one embodiment, the adhesive is a hot melt
adhesive that disperses in a pH greater than about 8. In another
embodiment, the adhesive disperses in a pH greater than about 9.
Such a pH sensitive adhesive can enhance the ability of a fabric to be
disposed of in alkaline-aqueous solutions sometimes used in medical
applications.
Fabrics having a multi-component structure can also be
entangled as described above. Specifically, one or more components,
or the entire fabric, can be hydroentangled to enhance strength
characteristics of the fabric. For example, in one embodiment, one of
the layers of the multi-component structure is made from pulp fibers
that have been hydroentangled. In another embodiment, the multi-
component structure includes a web of polyvinyl alcohol fibers
adhered to a web of pulp fibers. The entire multi-component structure,
in this embodiment, can be entangled such that the pulp fibers
sufficiently entangle with the polyvinyl alcohol fibers to increase the
strength of the fabric.
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Other objects, features and aspects of the present invention are
discussed in greater detail below.
Detailed Description
Reference now will be made in detail to various embodiments
of the invention, one or more examples of which are set forth below.
Each example is provided by way of explanation of the invention, not
limitation of the invention. In fact, it will be apparent to those skilled in
the art that various modifications and variations can be made in the
present invention without departing from the scope or spirit of the
invention. For instance, features illustrated or described as part of one
embodiment, can be used on another embodiment to yield a still
further embodiment. Thus, it is intended that the present invention
cover such modifications and variations as come within the scope of
the appended claims and their equivalents. Other objects, features
and aspects of the present invention are disclosed in or are obvious
from the following detailed description. It is to be understood by one
of ordinary skill in the art that the present discussion is of exemplary
embodiments only, and is not intended as limiting the broader aspects
of the present invention.
In general, the present invention is directed to a fabric for
various uses, such as a garment, that is dispersible when contacted
with an aqueous solution. It should be understood that an aqueous
solution can include any liquid or solution, such as water or solutions
thereof. In particular, a fabric of the present invention contains at least
one component that is soluble in hot water and at least one
component that is dispersible, but not completely soluble. It has been
discovered that a fabric of the present invention can partially dissolve
in hot water to aid in waste management. Moreover, it has also been
discovered that a fabric of the present invention can retain enhanced
strength characteristics and dimensional integrity during everyday use.
For example in one embodiment, polyvinyl alcohol fibers and pulp
fibers are incorporated into a fabric such that the polyvinyl alcohol
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fibers can dissolve when the fabric is contacted with hot water,
whereas the pulp fibers only disperse into individual fibers.
As stated, a fabric of the present invention includes at least one
hot water soluble component. As used herein, "hot water" generally
refers to liquids having a temperature sufficient to dissolve a
component, whereas "cold water" generally refers to liquids having any
other temperature. In particular, the hot water soluble fibers of the
present invention are normally dissolvable at temperatures above
about 37°C. In one embodiment, the fibers dissolve in water at
temperatures above about 80°C, and in particular, between about
80°C to about 95°C.
Any fibers that can be dissolved in water or an aqueous solution
having a certain temperature, such as above about 37°C, can
generally be used in the present invention as the hot water soluble
component. In one embodiment, the hot water soluble component is
made from polyvinyl alcohol fibers. As stated above, one embodiment
of polyvinyl alcohol fibers are those that dissolve in water at a
temperature between about 80°C to about 95°C. In one embodiment,
for example, polyvinyl alcohol fibers are provided that dissolve in water
at 92°C. In another embodiment, polyvinyl alcohol fibers are provided
that dissolve in water at 80°C. Commercially available polyvinyl
alcohol fibers that are suitable for use in the present invention are VPB
201 or 304 staple fibers made by Kuraray Company, Ltd. (Japan).
Other examples of suitable polyvinyl alcohol fibers are disclosed in
U.S. Patent No. 5,268,222 to Honeycutt, which is herein incorporated
by reference.
In accordance with the present invention, a fabric of the present
invention also includes at least one component that is dispersible. It
has been discovered that a fabric of the present invention can have
increased dimensional stability and strength by utilizing dispersible
fibers in conjunction with hot water soluble fibers, as described above.
Moreover, although a fabric of the present invention is not completely
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hydrolytically degradable, it can nevertheless be substantially
disposed of when the hot water soluble fibers dissolve in a hot liquid.
Any material that is dispersible in water can generally be used
as a dispersible component of the present invention. In particular,
components that are dispersible and do not significantly affect the
solubility of other components within the fabric can be utilized in
accordance with the present invention. In one embodiment, the hot
water dispersible component is made from pulp fibers either alone or
in combination with other fibers. For instance, the pulp fibers can be
softwood fibers having an average fiber length of greater than 1 mm
and particularly from about 2 to 5 mm based on a length-weighted
average. Such fibers can include Northern softwood kraft fibers,
redwood fibers, pine fibers, spruce fibers, or a combination thereof.
Secondary fibers obtained from recycled materials may also be used.
In a preferred embodiment, a dispersible component of the present
invention is made from about 50%-70% black spruce fibers and about
25%-50% jack pine fibers.
In addition to the above components, other chemicals and/or
additives can also be employed in forming a fabric of the present
invention. In general, any chemical that does not significantly affect
the solubility and/or dispersability of fibers within a fabric of the
present invention can be added. For instance, in one embodiment,
anionic or cationic dyes can be used to impart a particular color to the
resulting fabric. An example of an anionic dye suitable for use in the
present invention is Pergasol Blue 2R made by Ciba Specialty
Chemicals. Moreover, an example of a suitable cationic dye is Cartsol
Blue GDF. A dye can generally be applied to a fabric of the present
invention by any manner known in the art, such as by saturating the
fabric in the dye or utilizing a weir device installed onto a
hydroentangling line. In addition to dyes, surface chemicals can also
be added to the fabric to provide water or alcohol repellancy.
Various embodiments of a fabric made according to the present
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invention will now be described. In one embodiment, the fabric is
made from polyvinyl alcohol and pulp fibers. It should be understood,
however, that various other components and/or materials may be used
in accordance with the present invention and that the following
description is for exemplary purposes only. In particular, it should be
understood that the following concentration ranges and parameters
can widely vary depending upon the particular application.
In this regard, a fabric of the present invention typically contains
a hot water soluble component. In one embodiment, the hot water
soluble component is made from polyvinyl alcohol fibers. Moreover, in
some embodiments, the hot water soluble component can be formed
into a web using any technique known in the art for making nonwoven
webs. Such nonwoven techniques useful for making polymer sheets
include spun bonding, melt blowing, wet laying, hydroentangling with
cold water, and/or thermally bonding.
In addition, in one embodiment, the hot water soluble
component is carded into a carded web as is well-known in the art.
For example, in a preferred embodiment, a web of polyvinyl alcohol
fibers is formed by carding the fibers into a carded web. Although not
required, the fibers can also be cross-layed (cross-lapped) in the
machine direction and/or cross machine direction and thereafter
thermally bonded to achieve further strength. In one embodiment, the
web of polyvinyl alcohol fibers has a basis weight above about 40
grams per square meter.
As discussed above, one embodiment of a fabric of the present
invention also includes a generally non-soluble, dispersible component
that includes pulp fibers either alone or in combination with other
fibers. In general, by increasing the amount of pulp fibers added, the
strength of the fabric can often increase proportionately. For example,
the pulp fibers typically comprise up to about 55% of the fabric by
weight. In one embodiment, the pulp fibers comprise up to about 40%
by weight of the fabric, and even more preferably, up to about 20%.
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For instance, in one embodiment, the pulp fibers comprise 37% by
weight of the fabric. In another embodiment, the pulp fibers comprise
17% by weight of the fabric. Although it is normally desired to utilize
such low levels of pulp fibers, it should also be understood that the
5 acceptable range of pulp fiber concentrations can vary drastically
depending on the particular application as well as on the amount and
type of other materials present. Thus, pulp fiber concentrations
greater those recited above may be equally suitable in some
embodiments.
10 When adding dispersible fibers, it is typically desired to
entangle the fibers with the hot water soluble fibers to form a stronger
web. In particular, any method known in the art, such as air entangling
or hydraulic entangling, can be used in the present invention to
entangle different fibers together. For example, in one embodiment;
dispersible fibers are entangled into a web of hot water soluble fibers.
In another embodiment, dispersible fibers are combined with hot water
soluble fibers in a liquid suspension to form a web that is thereafter
entangled. In still another embodiment, a sheet of dispersible fibers is
adhered to a sheet of hot water soluble fibers by an adhesive to form a
multi-component structure that is thereafter entangled. In addition to
the above mentioned embodiments, other methods of entangling
dispersible fibers with hot water soluble fibers are equally suitable and
can be used in the present invention.
In one embodiment, pulp fibers are hydraulically entangled into
a carded web of polyvinyl alcohol fibers to form a fabric having
increased strength. Hydroentangled webs, which are also known as
spunlace webs, refer to webs that have been subjected to columnar
jets of a fluid that cause the fibers in the web to entangle. Particularly
when fibers of different lengths are present, hydroentangling can
increase the strength of the web by entangling the shorter fibers
around the longer fibers. Thus, according to the present invention, the
strength of the fabric can be increased by hydraulically entangling the
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dispersible fibers into a web of hot water soluble fibers.
Another embodiment of a fabric made according to the present
invention can include the use of hot water soluble fibers, dispersible
fibers, and an adhesive that is dispersible in an aqueous environment.
Suitable hot melt adhesives, for example, are described in U.S. Patent
No. 5,527,845 to Strelow et al., which is incorporated herein by
reference. One such adhesive disclosed in Strelow includes about
10% to about 80%, by weight, of an alkali soluble polymer; about 0 to
about 30%, by weight, of a poly (vinyl methyl ether); about 30% to
about 70%, by weight, of a tackifying resin; and about 5% to about
30%, by weight, of a suitable plasticizer. Examples of suitable
adhesives include HX 9236-01 or HX 9237-01 hot melt adhesives,
which are obtainable from ATO Findley, Inc..
In one embodiment, the hot melt adhesive is also capable of
dispersing in an alkaline aqueous solution. The use of such a pH
sensitive adhesive can result in a fabric that is compatible with
dispersion techniques and conditions used by hospitals. For instance,
hospitals typically prefer to dispose of fabrics using an aqueous-alkali
bath containing detergent and bleach (or other suitable caustics).
Many of these baths have a pH of about 8 or greater. Thus, in some
embodiments, a fabric of the present invention can include an
adhesive that disperses in an aqueous environment having a pH
greater than about 8, and in other embodiments, greater than about 9.
It should be understood, however, that adhesives which disperse at
pH levels less than about 8 can also be utilized in the present
invention, particularly when used in applications that employ an
aqueous solution having a pH less than about 8 to dispose of a fabric.
One example of a multi-component fabric of the present
invention can be formed as follows. It should be understood, however,
that a multi-component fabric of the present invention is not limited to
the particular embodiment described below. In this regard, hot water
soluble polyvinyl alcohol fibers can be formed into a web of carded
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staple fibers and thermally point bonded into a fabric. Thereafter, a
hot melt adhesive, such as meltblown fibers of HX 9236-01 or HX
9237-01 hot melt adhesives, can be attached to the web of polyvinyl
alcohol fibers. Various plies can then be applied to the carded web of
polyvinyl alcohol fibers by the adhesive. For example, in one
embodiment, a dispersible low strength tissue can be attached to the
hot water soluble carded web of polyvinyl alcohol fibers by the hot melt
adhesive. Typically, a low strength tissue can be made from pulp
fibers. One commercially available example of such a water
dispersible low strength tissue is Owensboro bath tissue base, type
72000 made by Kimberly-Clark Corporation of Neenah, Wisconsin.
Moreover, in another embodiment, a second carded web or film of hot
water soluble polyvinyl alcohol fibers can be attached onto the first
carded web of polyvinyl alcohol fibers by the hot melt adhesive.
In general, when forming a multi-component structure according
to the present invention, either one or more layers of the structure can
be entangled. For example, when dispersible fibers are adhered to
hot water soluble fibers as described above, the resulting multi-
component structure can be hydraulically entangled as described
above to provide further strength to the fabric. In one embodiment,
when pulp fibers are adhered to polyvinyl alcohol fibers as described
above, the resulting multi-component structure can also be
hydraulically entangled to form a stronger fabric.
The present invention may be better understood with reference
to the following examples.
EXAMPLE
The ability of a fabric of the present invention to provide
increased strength was demonstrated. Two types of polyvinyl alcohol
fibers were used as the hot water soluble component for the samples,
i.e. one being soluble in water at 80°C (VPB 201 ), the other being
soluble in water at 92°C (VPB 304).
As shown below in Table 1, the five samples are represented
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by the letters "A", "B", "C", "D", and "E". Samples A & B contained
VPB 201 fibers bonded at temperatures of 386°F and 390°F,
respectively. Samples C, D, and E contained VPB 304 fibers bonded
at temperatures of 390°F, 440°F, and 440°F, respectively.
The
bonding of the polyvinyl alcohol fibers above was achieved using
thermal point bonding without the addition of any additives. Various
characteristics of Samples A - E are shown below.
Table 1: Characteristics of Samples A - E
Sample PVA Thermal Basis Tensile Normalized
Type Point Wt. Strength Strength
Bonding (GSM) (GMs) (GMs/GSM)
Temp
F
A VPB 386 37 60 38 1.62
201
B VPB 390 54 225 94 4.17
201
C VPB 390 43 686 15.95
304
D VPB 440 30 888 29.60
304
E VPB 440 47 1384 29.45
304 554
From the above samples, varying degrees of
hydroentanglement and/or pulp content were tested. In particular,
pulp fibers were wet formed onto a forming wire and then transferred
onto the various samples. A pulp stock (12 Ibs of 50%-70% black
spruce fibers and 25%-50% jack pine fibers, per 3000 gallons of
water) was used as the dispersible component for each sample. The
conditions and equipment utilized were similar to that of U.S. Patent
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No. 5,587,225 to Griesbach et al., which is incorporated herein by
reference. Specifically, pilot line equipment, which includes 103 A-M
PET hydroentangling wire, 6/40/1 strips in each manifold, and three
manifolds, was used for the appropriate hydroentangling.
The strengths of the above sample fabrics at varying degrees of
hydroentanglement and/or pulp content were then determined. Pulp
content was varied for the samples by adjusting the degree of
hydroentangling and the speed of the wire supporting the fibers under
the hydroentangling manifolds. Moreover, various hydroentangling
energies were utilized to determine the effect hydroentangling on
fabric strength. Specifically, the energies (i.e. Energy/Mass) used are
described in U.S. Patent No. 5,023,130 to Simpson et al., which is
incorporated herein by reference.
For each set of conditions, the tensile strength was determined
using modified ASTM methods E4-83a and E74-93. In particular, this
test used a 3" x 6" specimen with the long direction corresponding to
the orthogonal direction, having the least amount of fibers orientation
(cross direction or CD) after fabrication. The entire width of the
specimen is held between 1" x 3" jaws spaced 3 inches apart. As the
specimen was extended at 300 mm/min, the resisting force was
measured with respect to the amount of extension. The tensile
strength was the maximum load before the specimen ruptures. For
each sample and set of conditions, multiple specimens were tested to
determine tensile strength. The average of these tensile strength
values was calculated for each set of conditions and reported in
Tables 2-6, along with the standard deviation for each average value.
The data for each of Tables 2-6 are arranged in ascending
order based on the ratio of normalized strength values as compared to
the normalized strength of the sample with 100% polyvinyl alcohol
fibers as indicated in Table 1. The normalized strength values
generally measure strength increases or decreases based on
hydroentangling and pulp content conditions, taking into account that
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the fabric will inevitably have some increase in strength due to
increases in other parameters such as basis weight. The results are
shown below in Tables 2-6.
TABLE 2: Impact of Pulp and Hydroentangling on Strength of
5 Sample A
Energy/Mass Basis Tensile Normalized Ratio
Pulp (KW-hr/kg) Wt. Strength Strength
(GSM) (GMs) (GSM/GMs)
0 0 37 60 + 38 1.62 100%
0 1.325 29 126 + 28 4.345 268%
10 37.0 0.835 46 2185 + 133 47.5 2929
35.6 1.751 45 3245 + 346 72 4447
TABLE 3: Impact of Pulp and Hydroentangling on Strength of
Sample B
15 % Energy/ MassBasis Tensile Normalized Ratio
Pulp (KW-hr/kg) Wt. Strength Strength
(GSM) (GMs) (GSM/GMs)
0 0.985 39 48 + 12 1.23 29%
0 0 54 225 + 94 4.167 99%
0 2.02 39 414 + 76 10.62 253%
0 1.713 46 606 + 167 13.17 314%
36.9 0.591 65 3045 46.85 1115
767
35.9 1.231 64 5890 92.03 2191
473
45.3 2.101 75 8700 116 2762
520
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TABLE 4: Impact of Pulp and Hydroentangling on Strength of
Sample C
Energy/Mas Basis Tensile NormalizedRatio
Pulp s (KW-hr/kg)Wt. Strength Strength
(GSM) (GMs) (GM/GMs)
0 1.921 41 164 + 46 4 25%
0 0.873 44 227 65 5.16 32%
0 0 43 686 15.95 100%
21.8 0.699 55 1664 + 324 30.25 189%
18.9 1.486 53 ~ 4156 + I 78.42 490%
650 I
TABLE 5: Impact of Pulp and Hydroentangling on Strength of
Sample D
% Energy/Mas Basis Tensile NormalizedRatio
Pulp s (KW-hr/kg)Wt. Strength Strength
(GSM) (GMs) (GM/GMs)
0 3.030 26 317 48 12.19 41
0 6.305 25 323 46 12.92 44%
35.0 1.970 40 1069 192 26.73 90%
0 0 30 888 29.6 100%
51.9 2.918 54 1733 + 150 32.09 108%
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TABLE 6: Impact of Pulp and Hydroentangling on Strength of
Sample E
Energy/Mass Basis Tensile Normalized Ratio
Pulp (KW-hr/kg) Wt. Strength Strength
(GSM) (GMs) (GM/GMs)
0 3.425 46 358 + 7.78 26%
93
0 1.751 45 469 + 10.42 35%
318
0 0.817 47 1132 + 24.09 82%
629
0 0 47 1384 + 29.44 100%
554
25.8 0.620 62 2188 + 34.29 120%
510
24.6 1.291 61 3770 + 61.80 210%
386
42.5 1.970 80 7054 + 88.18 299%
957
The results shown in Tables 2-6 clearly demonstrate that
hydroentangling and pulp content can increase the strength of a fabric.
Referring to Tables 2 or 3, for example, a fabric containing only
underbonded polyvinyl alcohol fibers generally increased in strength
after hydroentangling. However, as pulp was added to the fabric and
hydroentangling was utilized, the normalized strength values increased
dramatically.
Similarly, Tables 4-6 also demonstrated the ability of pulp
content and hydroentangling to increase strength. Fabrics containing
only optimally bonded polyvinyl fibers, as shown in Table 4, 5, or 6,
demonstrated a general decrease in strength after hydroentangling. In
contrast, with the addition of pulp to the optimally bonded fibers, the
normalized strengths for the hydroentangled fabrics increased in
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almost every instance.
Although various embodiments of the invention have been
described using specific terms, devices, and methods, such
description is for illustrative purposes only. The words used are words
of description rather than limitation. It is to be understood that
changes and variations may be made by those of ordinary skill in the
art without departing from the spirit or the scope of the present
invention, which is set forth in the following claims. In addition, it
should be understood that aspects of the various embodiments may
be interchanged both in whole or in part. Therefore, the spirit and
scope of the appended claims should not be limited to the description
of the preferred versions contained therein.
