U.S. patent application number 10/965403 was filed with the patent office on 2005-06-23 for 100% synthetic nonwoven wipes.
Invention is credited to Gorley, Ronald Thomas, Pung, David John, Sherry, Alan Edward.
Application Number | 20050133174 10/965403 |
Document ID | / |
Family ID | 35610054 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050133174 |
Kind Code |
A1 |
Gorley, Ronald Thomas ; et
al. |
June 23, 2005 |
100% synthetic nonwoven wipes
Abstract
The present invention relates to wipes comprising at least one
layer of a 100% synthetic nonwoven web. The wipes may be provided
as a single layer of nonwoven web, or may be provided in a laminate
material, such as one comprising spunlaid-meltblown-spunlaid (SMS)
webs. The 100% synthetic nonwoven webs of the present invention may
be made via a process comprising a fiber laying step selected from
the group consisting of spunlaying, meltblowing, carding,
airlaying, wetlaying and combinations thereof. The 100% synthetic
nonwoven webs of the present invention may be made via a process
comprising a fiber bonding step selected from the group consisting
of hydroentanglement, cold calendering, hot calendering, air thru
bonding, chemical bonding, needle punching and combinations
thereof. The nonwoven webs may also comprise one or more
polyolefins. In one embodiment of the present invention, the
nonwoven webs may be spunlaid and HET.
Inventors: |
Gorley, Ronald Thomas;
(Cincinnati, OH) ; Pung, David John; (Loveland,
OH) ; Sherry, Alan Edward; (Cincinnati, OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Family ID: |
35610054 |
Appl. No.: |
10/965403 |
Filed: |
October 14, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10965403 |
Oct 14, 2004 |
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10737129 |
Dec 15, 2003 |
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10737129 |
Dec 15, 2003 |
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09671718 |
Sep 27, 2000 |
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6716805 |
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60156286 |
Sep 27, 1999 |
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Current U.S.
Class: |
162/108 ;
510/438 |
Current CPC
Class: |
D04H 1/54 20130101; C11D
17/049 20130101; D04H 1/492 20130101; A45D 37/00 20130101; A45D
2200/1018 20130101; A45D 2200/1036 20130101; B08B 1/00 20130101;
A47L 13/16 20130101 |
Class at
Publication: |
162/108 ;
510/438 |
International
Class: |
D21H 011/00 |
Claims
What is claimed is:
1. A wipe comprising at least one layer of a 100% synthetic
nonwoven web, wherein said wipe is: characterized by saturation
loading of from about 1.5 to about 6.0 grams of liquid composition
per gram of said wipe; and premoistened with said liquid
composition having a surface tension of below about 35 dynes per
cm.
2. The wipe according to claim 1, wherein said liquid composition
has a surface tension of below about 30 dynes per cm.
3. The wipe according to claim 1, wherein said wipe is
characterized by saturation loading from about 2.0 to about 4.0
grams of liquid composition per gram of said wipe.
4. The wipe according to claim 1, wherein said wipe has a basis
weight greater than about 30 grams per square meter.
5. The wipe according to claim 1, wherein said wipe has a basis
weight from about 40 to about 70 grams per square meter.
6. The wipe according to claim 1, wherein said wipe has a
cross-direction bending moment of less than about 0.09 (grams
force.multidot.centimeter.s- up.2) per centimeter.
7. The wipe according to claim 1, wherein said wipe has an
absorptive capacity of greater than about 4 grams of liquid
composition per gram of said wipe.
8. The wipe according to claim 1, wherein said wipe has an
absorptive capacity of greater than about 8 grams of liquid
composition per gram of said wipe.
9. The wipe according to claim 1, wherein said 100% synthetic
nonwoven web is made via a process comprising a fiber laying step
selected from the group consisting of spunlaying, meltblowing,
carding, airlaying, wetlaying and combinations thereof.
10. The wipe according to claim 1, wherein said 100% synthetic
nonwoven web is made via a process comprising a fiber bonding step
selected from the group consisting of hydroentanglement, cold
calendering, hot calendering, air thru bonding, chemical bonding,
needle punching and combinations thereof.
11. The wipe according to claim 1, wherein said 100% synthetic
nonwoven web is comprised by one or more polyolefins.
12. The wipe according to claim 1, wherein said wipe is comprised
by a laminate of two or more layers of said 100% synthetic nonwoven
web.
13. A wipe comprising at least one layer of a 100% synthetic
nonwoven web, wherein said web is spunlaid and hydroentangled to
form said wipe, and further wherein said wipe is: characterized by
saturation loading from about 1.5 to about 6.0 g of liquid
composition per gram of said wipe; and premoistened with a liquid
composition having a surface tension of below about 35 dynes per
cm.
14. The wipe according to claim 13, wherein said liquid composition
has a surface tension of below about 30 dynes per cm.
15. The wipe according to claim 13, wherein said wipe is
characterized by saturation loading from about 2.0 to about 4.0
grams of liquid composition per gram of said wipe.
16. The wipe according to claim 13, wherein said wipe has a basis
weight greater than about 30 grams per square meter.
17. The wipe according to claim 13, wherein said wipe has a basis
weight from about 40 and about 70 grams per square meter.
18. The wipe according to claim 13, wherein said wipe has a
cross-direction bending moment of less than about 0.09 (grams
force.multidot.centimeter.sup.2) per centimeter.
19. The wipe according to claim 13, wherein said wipe has an
absorptive capacity of greater than about 4 grams of liquid
composition per gram of said wipe.
20. The wipe according to claim 13, wherein said wipe has an
absorptive capacity of greater than about 8 grams of liquid
composition per gram of said wipe.
21. The wipe according to claim 13, wherein said liquid composition
is comprised by bleach.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S. patent
application Ser. No. 10/737,129, filed Dec. 15, 2003, which is a
continuation of U.S. patent application Ser. No. 09/671,718, filed
Sep. 27, 2000, which claims the benefit of U.S. Provisional Patent
Application No. 60/156,286, filed Sep. 27, 1999.
FIELD OF THE INVENTION
[0002] This invention relates to 100% synthetic nonwoven wipes
comprising at least one layer of a 100% synthetic nonwoven web. The
wipes, which may be premoistened, can be used in a variety of
applications. Wipe applications may include use in surface
cleansing and surface cleansing products, as well as use as or in,
absorbent products.
BACKGROUND OF THE INVENTION
[0003] Nonwoven webs and processes for making them are known in the
art. Processes for making nonwoven webs may comprise three steps:
fiber laying, precursor web formation, and fiber bonding. The fiber
laying step may be comprised of the spunlaying, meltblowing,
carding, airlaying, wetlaying and combinations thereof, of the
fibers comprising the web onto a forming surface. The step of
precursor web formation may prevent the fibers comprising the web
from coming apart during the bonding step. Precursor web formation
may be performed via a pre-bonding step, such as one that is
chemical or mechanical in nature. The bonding step may then impart
strength to the finished web. The bonding step may be comprised of
subjecting the fibers comprising the web to hydroentanglement
(HET), cold calendering, hot calendering, air thru bonding,
chemical bonding, needle punching, and combinations thereof.
[0004] In general, precursor web formation may add to the cost of
making nonwoven webs by requiring the separate step of pre-bonding
the fibers comprising the web. Likewise, the pre-bonding steps may
affect the properties of the nonwoven web. For example, while
pre-bonding may increase the durability of a nonwoven web, it may
also increase its stiffness and, in turn, decrease its softness to
the touch. Examples of processes requiring precursor web formation
and the nonwoven materials made thereby may be found in: U.S. Pat.
Nos. 5,023,130, 5,573,841, 6,321,425, 6,430,788, and 6,430,788;
European Patent EP 0 333 211 B1; International Published
Application WO 01/51693 A1; and U.S. Patent Application Publication
Number 2004/0010894.
[0005] Processes known in the art for making nonwoven webs may
produce nonwoven webs having sufficient strength in the machine
direction; however, they may not produce nonwoven webs that also
have sufficient strength in the cross-direction. When such nonwoven
webs are pulled in the cross-direction, they may stretch and
ultimately tear.
SUMMARY OF THE INVENTION
[0006] 100% synthetic nonwoven webs known in the art typically do
not have the absorptive capacity of webs that are at least
partially non-synthetic. Thus, a 100% synthetic nonwoven web having
good machine and cross-directional strengths, as well as softness
and high absorptive capacity may be desired. Moreover, the
provision of such improved material from a single 100% synthetic
raw material via a continuous in-line process in the absence of
precursor web formation may also be desirable. Additionally, a wipe
comprising at least one layer of such a 100% synthetic nonwoven web
may be desirable.
[0007] The present invention relates to wipes comprising at least
one layer of a 100% synthetic nonwoven web. The wipes may be
provided as a single layer of nonwoven web, or may be provided in a
laminate material, such as one comprising
spunlaid-meltblown-spunlaid (SMS) webs. The wipes may have a
saturation loading of from about 1.5 to about 6.0 g of liquid
composition per g of the wipe, or even from about 2.0 to about 4.0
g of liquid composition per g of the wipe. The wipes may be
pre-moistened with a liquid composition having a surface tension of
below about 35 dynes/cm, or even below about 30 dynes/cm. The wipes
may have a basis weight that is greater than about 30 grams per
square meter (gsm), or even a basis weight that is from about 40
and about 70 gsm. The cross-direction bending moment of the wipes
may be less than about 0.09 (gf-cm.sup.2) per cm. The wipes may
have an absorptive capacity that is greater than about 4 grams of
liquid composition per gram of the wipe, or even greater than about
8 grams of liquid composition per gram of the wipe. The 100%
synthetic nonwoven webs of the present invention may be made via a
process comprising a fiber laying step selected from the group
consisting of spunlaying, meltblowing, carding, airlaying,
wetlaying and combinations thereof. The 100% synthetic nonwoven
webs of the present invention may be made via a process comprising
a fiber bonding step selected from the group consisting of
hydroentanglement, cold calendering, hot calendering, air thru
bonding, chemical bonding, needle punching and combinations
thereof. The nonwoven webs may also comprise one or more
polyolefins. In one embodiment of the present invention, the
nonwoven webs may be spunlaid and HET.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The present invention may relate to wipes comprising at
least one layer of a 100% synthetic nonwoven web. The 100%
synthetic nonwoven web may be made in a continuous in-line process,
wherein at least one layer of fibers may be bonded together by HET,
cold calendering, hot calendering, air thru bonding, chemical
bonding, needle punching and combinations thereof, to form the web.
The aforementioned bonding processes may be performed in the
absence of precursor web formation via pre-bonding of the fibers
comprising the web. The resulting 100% synthetic nonwoven webs may
not only have strength in the machine and cross directions, but may
also be soft and have a high absorptive capacity without the
integration of non-synthetic fibers such as wood pulp for
example.
[0009] The present invention may relate to wipes comprising at
least one layer of a 100% synthetic nonwoven web, wherein the web
is made through a process comprised of forming the nonwoven web
from at least one layer of fibers. Such a process may be performed
in the absence of a pre-bonding treatment of the fibers prior to
subjecting them to HET by a plurality of high pressure water jets
for example. The properties of the plurality of high pressure water
jets may be varied to control some of the properties obtained in
the resulting nonwoven web and the wipe ultimately comprised by the
nonwoven web. Additionally, the present invention may provide that
the fibers comprising the nonwoven web layer(s), be made from a
100% thermoplastic monocomponent fiber, such as a polyolefin or
polyester. In addition or in the alternative, the present invention
may provide that the fibers be biconstituent fibers. In addition or
in the alternative, the present invention may provide that the
fibers of the wipe layer(s) be made from a 100% thermoplastic
bicomponent fiber, such as a sheath/core fiber or side by side
fiber of polyethylene/polypropylene.
[0010] Different characteristics may be imparted to the wipes of
the present invention depending upon the desired use. For example,
the wipe may be made hydrophilic using surfactants. The wipe may
also be premoistened.
[0011] The wipes of the present invention may be useful in
absorbent products, such as feminine hygiene and adult incontinence
products. The wipes of the present invention may also comprise dry
or wet wipes that are useful for dry and/or wet surface cleaning,
dry and/or wet body cleansing, as well as for various combinations
of uses.
[0012] The term "fiber" as used herein, means a unit which forms
the basic element of the nonwoven web disclosed herein. The term
"fiber" may be used interchangeably with the term "filament".
[0013] As used herein, the term "continuous fiber" refers to a
fiber of an indefinite or extreme length. The term "continuous
fiber" is may be used interchangeably with the term "continuous
filament".
[0014] "Monocomponent fibers" as used herein, refers to
thermoplastic fibers that are made from one polymer.
[0015] "Bicomponent fibers" as used herein, refers to thermoplastic
fibers that are comprised of at least two different polymers,
wherein the polymers may be in a sheath/core or a side by side
arrangement. Bicomponent fibers comprised of polymers in a
sheath/core arrangement, are comprised of a core fiber made from
one polymer that is encased or substantially encased within a
thermoplastic sheath made from a different polymer. The polymer
comprising the sheath often melts at a different, typically lower,
temperature than the polymer comprising the core. As a result,
these bicomponent fibers provide thermal bonding due to melting of
the sheath polymer, while retaining the desirable strength
characteristics of the core polymer. Additionally, the bicomponent
fibers of the present invention may be concentric, eccentric and
combinations thereof.
[0016] The term "wipes" as used herein is a general term used to
describe an article that is comprised by one or more layers of web.
When wipes are comprised by more than one web layer, the web layers
may or may not be bonded together via known consolidation processes
including, but not limited to, HET, cold calendering, hot
calendering air thru bonding, chemical bonding and the like.
[0017] The term "web" as used herein, refers to a layer or layers
of 100% synthetic fibers that are formed by various processes in
the absence of any bonding of the fibers within the layer or
between the layers comprising the web. Processes of use may include
spunlaying, meltblowing, carding, airlaying, wetlaying and
combinations thereof.
[0018] "Synthetic" as used herein, refers to a material based on
synthetic organic polymers such as polyolefins for example.
[0019] "Non-synthetic" as used herein, refers to man-made and
natural fibers.
[0020] "Laminate" as used herein, refers to superimposed layers of
web.
[0021] "Biconstituent fibers" as used herein, refers to
thermoplastic fibers that are comprised by a blend of two or more
thermoplastic polymers. Biconstituent fibers generally do not have
the core/sheath arrangement of "bicomponent fibers" as used
herein.
[0022] "Liquid composition" as used herein, refers to any liquid,
including, but not limited to a pure liquid such as water, a
colloid, an emulsion, a suspension, a solution and mixtures
thereof.
[0023] "Softness" as used herein may be quantified by the
measurable physical parameter of bending moment. Bending moment is
typically expressed in (grams force.multidot.centimeter.sup.2) per
centimeter, which is abbreviated as (gf-cm.sup.2) per cm.
[0024] "Premoistened wipes" as used herein, are wipes which are
moistened, such as by wetting the wipe with a liquid composition
prior to use by the consumer. "Premoistened wipes" as used herein,
may also refer to wipes which are moistened prior to packaging in a
generally moisture impervious container or wrapper. Such
premoistened wipes, which can also be referred to as "wet wipes"
and "towelettes", may be suitable for use in cleaning babies, as
well as older children and adults. Such premoistened wipes may also
be of use, or comprise articles that are useful for, the
application of substances to the body, like make-up, skin
conditioners, ointments and medications. Such premoistened wipes
may also be of use, or comprise articles that are useful for,
cleaning or grooming pets or may even be of use, or comprise
articles that are useful for, general cleansing of surfaces and
objects, such as household kitchen and bathroom surfaces,
eyeglasses, exercise and athletic equipment, automotive surfaces
and the like. "Premoistened wipes" as used herein may even include
dry wipes that are impregnated with liquid compositions, including
but not limited to cleaning agents. Such "Premoistened wipes" might
be wetted by the consumer prior to use. Furthermore, "premoistened
wipes" as referred to herein may in addition, or in the
alternative, include wet wipes that have been premoistened with
liquid compositions, including but not limited to liquid
compositions such as cleaning agents or lotions.
[0025] "Saturation loading" as used herein refers to the amount of
liquid composition applied to the wipe. In general, the amount of
liquid composition applied may be chosen in order to provide
maximum benefits to the end product comprised by the wipe.
Saturation loading is typically expressed as grams of liquid
composition per gram of dry wipe.
[0026] As used herein, the term "basis weight" means the weight per
unit area of the wipe, or the web(s) comprising the wipe. One
method of determining basis weight, therefore, is to weigh a known
area sample that is representative of the wipe or the web(s)
comprising the wipe. The units of basis weight are typically
expressed as grams per square meter (gsm).
[0027] "Surface tension" as used herein, refers to the force at the
interface between a liquid composition and air. Surface tension is
typically expressed in dynes per centimeter (dynes/cm).
[0028] The term "surfactant" as used herein, refers to materials
which preferably orient toward an interface. Surfactants include
the various surfactants known in the art, including nonionic
surfactants, anionic surfactants, cationic surfactants, amphoteric
surfactants, zwitterionic surfactants and mixtures thereof.
[0029] As used herein with respect to nonwoven webs, the term
"machine-direction" or "MD" refers to the direction of web travel
as the nonwoven web is produced, for example on commercial nonwoven
making equipment. Likewise, the term "cross-direction" or "CD"
refers to the direction perpendicular to the machine direction and
parallel to the general plane of the layered fibrous product and/or
layered fibrous structure. With respect to individual wipes, the
terms refer to the corresponding directions of the wipe with
respect to the web used to produce the wipe. These directions are
carefully distinguished herein because the mechanical properties of
a nonwoven web may differ, depending on how the nonwoven web is
oriented during testing. For example, tensile properties of a
nonwoven web may differ between the machine-direction and the
cross-direction, due to the orientation of the constituent fibers,
and other process-related factors.
[0030] "Comprising" as used herein means that various components,
ingredients or steps can be conjointly employed in practicing the
present invention. Accordingly, the term "comprising" encompasses
the more restrictive terms "consisting essentially of" and
"consisting of".
[0031] 100% Synthetic Nonwoven Web
[0032] The 100% wipe of the present invention is comprised of at
least one layer of a 100% synthetic nonwoven web, which in turn is
bonded by HET, cold calendering, hot calendering, air thru bonding,
chemical bonding, needle punching and combinations thereof. The
bonding process may be performed in the absence of any pre-bonding
of the fibers, such as through chemical and/or mechanical
pre-bonding for example. The nonwoven web may be comprised of a
single layer, multiple layers, multiple layers with an absorbent
core, and combinations thereof. Furthermore, the nonwoven web may
include other fiber layer(s) that have been formed by various
methods, including, but not limited to spunlaying, meltblowing,
carding, airlaying, wetlaying and combinations thereof, in the
absence of any bonding of the fibers to one another either within
or between the web layer(s). When the nonwoven-web is comprised of
a single layer, the fibers may be spunlaid. At least one of the
layers of the nonwoven web may be comprised of fibers that are
polymeric and continuous; as such, the present invention may
eliminate the need to use non-synthetic fibers.
[0033] To provide a nonwoven web with high strength in the machine
direction and cross-direction, with improved processability, both
during and after manufacture, the nonwoven web may have a basis
weight of from about 17 to about 150 gsm. In another embodiment,
the nonwoven web may have a basis weight of from about 30 to about
100 gsm. In yet a further embodiment, the nonwoven web may have a
basis weight of about 40 to about 70 gsm.
[0034] The fibers used to form the nonwoven web may be made using
conventional extrusion apparatuses and techniques. The fibers may
themselves be made of thermoplastic polymer(s) and may be comprised
of monocomponent fibers, bicomponent fibers, biconstituent fibers
and combinations thereof. The monocomponent fibers may include:
polyolefins such as polypropylene and polyethylene; polyesters such
as polyethylene terephthalate; polyamides; copolyamides;
copolyesters; polyacrylates; polystyrenes; polyvinyl chloride;
polyvinylidine chloride; polyvinyl acetate; polyethylvinyl acetate;
polyacrylics; polyurethanes; polyhydroxyalkanoates; thermoplastic
elastomers; and mixtures of these and other known fiber forming
thermoplastic materials. In a further embodiment, the monocomponent
fibers may be polyolefins such as polypropylene and polyethylene.
In yet a further embodiment, the monocomponent fibers may be
polypropylene. Biconstituent fibers may be made of a blend or
blends of thermoplastic polymers including but not limited to
polyolefins such as polypropylene and polyethylene; polyesters such
as polyethylene terephthalate; polyamides; copolyamides;
copolyesters; polyacrylates; polystyrenes; polyvinyl chloride;
polyvinylidine chloride; polyvinyl acetate; polyethylvinyl acetate;
polyacrylics; polyurethanes; polyhydroxyalkanoates; thermoplastic
elastomers; and mixtures of these and other known fiber forming
thermoplastic materials. Bicomponent fibers of use in the present
invention may be concentric, eccentric, side by side and
combinations thereof; eccentric bicomponent fibers may be desirable
in providing more compressive strength at a given fiber thickness.
The bicomponent fibers may be comprised of a sheath/core of:
polyethylene/polypropylene, polyethylvinyl acetate/polypropylene,
polyethylene/polyester, polypropylene/polyester,
copolyester/polyester and mixtures of these and other known fiber
forming thermoplastic materials. In one embodiment of the
invention, bicomponent fibers of use may be those having a
polypropylene or polyester core and a lower melting copolyester,
polyethylvinyl acetate or polyethylene sheath. In a further
embodiment of the invention, suitable bicomponent fibers may be
comprised of a sheath/core of polyethylene/polypropylene. If the
nonwoven web is comprised of multiple layers, then each layer may
be of the same polymeric material. By using continuous fibers to
form the nonwoven web, the present invention may provide for a wipe
that not only has improved physical properties, but which may be
made using only one raw material in an in-line, continuous
process.
[0035] Varying the diameter of the fibers that comprise the 100%
synthetic nonwoven web may be an effective means of altering the
physical properties of the resulting web. The fibers may have a
diameter of from about 0.1 to about 50 microns, from about 1 to 40
microns, or from about 5 to 35 microns.
[0036] Various physical properties, including, but not limited to,
fluid-phobic, fluid-philic, fire retardant, absorbent, soft and
anti-static properties, may be imparted to at least one portion of
or to the entire 100% synthetic nonwoven web depending upon the use
to which the resulting wipe is to be applied. In addition or in the
alternative, physical properties including, but not limited to, low
force extensibility, textured stretch without elastics, soft high
elongation, flexibility, elasticity and extensibility may be
imparted to at least one portion of or to the entire 100% synthetic
nonwoven web via Solid State Formation (SSF) technology depending
upon the use to which the resulting wipe is to be applied. At least
one portion of the nonwoven web may include one or more of the
layers which are in their entirety modified as to a given property.
In the alternative, any pre-selected portion of the nonwoven web
may be modified as to the pre-selected property. The desired
property may be imparted to given areas in a variety of ways. SSF
technologies that may be applied to the HET nonwoven web(s) that
comprise the wipe may include, but are not limited to: ring
rolling, as described in U.S. Pat. No. 5,143,679; structural
elongation, as described in U.S. Pat. No. 5,518,801; consolidation,
as described in U.S. Pat. Nos. 5,914,084, 6,114,263, 6,129,801 and
6,383,431; stretch aperturing, as described in U.S. Pat. Nos.
5,628,097, 5,658,639 and 5,916,661; differential elongation, as
described in WO Publication No. 2003/0028165A1; and other SSF
technologies as described in U.S. Publication No. 2004/0131820A1
and U.S. application Ser. No. 10/737430.
[0037] To optionally make all or a portion of the nonwoven web
hydrophilic, the surface of the hydrophobic thermoplastic fibers
which comprise the web may be rendered hydrophilic by treatment
with a surfactant, such as a nonionic surfactant, anionic
surfactant or mixtures thereof. For example, surfactants, or
mixtures of surfactants, may be sprayed onto fibers, the fibers may
be dipped into the surfactant or mixture of surfactants, and/or the
surfactant or mixture of surfactants may be included as part of the
polymer melt in producing the thermoplastic fiber. In the latter
process, upon melting and re-solidification, the surfactant may
tend to remain at the surfaces of the thermoplastic fiber. Further
examples of suitable topical treatments for imparting
hydrophilicity to nonwoven webs are described in U.S. Pat. Nos.
5,709,747 and 5,885,656. Suitable surfactants of use in the polymer
melt include, but are not limited to, surfactants such as:
Brij.RTM. 76 manufactured by ICI Americas, Inc. of Wilmington, Del.
U.S.A.; various surfactants sold under the Pegosperse.RTM.
trademark by Glyco Chemical, Inc. of Greenwich, Conn. U.S.A.;
Standapol.TM., 1353A or 1480, as sold by Cognis Deutschland GmbH,
Dusseldorf Germany; and Stantex.RTM. S 6327, as sold by Cognis
Deutschland GmbH, Dusseldorf Germany. Surfactants suitable to be
sprayed onto the fibers or into which the fibers may be dipped to
impart hydrophilicity to the nonwoven web include, but are not
limited to, those described in U.S. Pat. Nos. 5,709,747 and
5,885,656. Surfactants may be applied to the thermoplastic fibers
at levels of, for example, from about 0.1 to about 1.0 grams per
square meter of thermoplastic fiber.
[0038] Hydroentanglement of the Thermoplastic Fibers
[0039] In one embodiment of the present invention, the nonwoven
wipe comprises at least one layer of a 100% synthetic nonwoven web,
which in turn includes at least one layer of fibers bonded by
hydroentanglement (HET). HET may be performed via the process
described in U.S. Patent Application Publication No. 2004/0010894
A1, which may be summarized as follows. Before entering into the
HET process, a desired spunlaid or meltblown layer (or layers) may
be produced by a conventional method for producing fibers. If the
layer is spunlaid, it may be comprised of continuous fibers. If the
layer is meltblown, it may be comprised of low denier fibers,
non-continuous fibers, and combinations thereof. The fibers may
then be laid onto a moving support (or moving supports). Examples
of useful moving supports include a moving mesh screen or a series
of moving supports, such as perforated godet rollers. When a
multi-layer material is being produced, second and subsequent
layer(s) may be laid sequentially upon the prior formed layer(s) on
the moving support. The layer or layers are then subjected to HET.
The moving support may be structured to extend or transfer the
layer or layers to the HET equipment such that the layer(s) is
(are) essentially continually supported. The support may serve to
maintain the structure of the layer(s) and to allow direct impact
of water on the layer(s) from the plurality of high pressure water
jets providing the HET while simultaneously preventing the
destruction of the layer(s) when the water impacts the
layer(s).
[0040] In the HET process itself, a plurality of water jets may be
positioned above the moving support(s). The moving support(s) may
be structured to allow for drainage of the water. The screen mesh
or perforations in the godet rollers may have openings with a
diagonal in the range of from about 0.1 to about 2.0 mm. The number
of water jets present and the pressure at which the water is
ejected are critical in determining the properties obtained in the
treated nonwoven material. The water jets may be positioned so as
to be spaced apart and to provide about 40 to about 50 water jets
per linear inch. The water jets may be arranged to cover the width
of the layer(s) being treated. A single line or a plurality of
lines of water jets may be used. The support(s) for the layer(s)
may move at a speed generally in a range of about 20 to about 250
meters per minute. Thus adequate exposure to the water jets may be
provided. Water may be fed under pressure through nozzles, at a
pressure of from about 20 to about 250 bar. Nozzle orifice
diameters may be from about 0.1 to about 0.2 mm in order to provide
the size of water streams desired.
[0041] Liquid Composition:
[0042] The wipes of the present invention may be premoistened with
any liquid composition having a surface tension of below about 35
dynes/cm, or below about 30 dynes/cm. The liquid composition may
for example be a colloid, an emulsion, a suspension, a solution and
mixtures thereof. Generally, the liquid composition is of
sufficiently low viscosity to impregnate the entire structure of
the wipe. In some other instances, the composition can be primarily
present at the wipe surface and to a lesser extend in the inner
structure of the wipe. In one embodiment, the liquid composition
may be releasably carried by the wipe; that is, the liquid
composition may be contained either in or on the web(s) comprising
the wipe, and may be readily releasable through the application of
force to the wipe, such as by wringing the wipe, or wiping a
surface, such as a child's bottom or a kitchen surface, with the
wipe.
[0043] The liquid composition of the present invention may be
comprised of any number of ingredients as long as the surface
tension of the liquid composition is below 35 dynes/cm, or even
below 30 dynes/cm. The ingredients may include, but are not limited
to: water, perfumes, soothing agents, fragrances, preservatives,
rheology modifiers, moisturizers, texturizers, colorants, medically
active ingredients, such as healing actives and skin protectants,
skin conditioning agents, surfactants, bleach, enzymes, detergents,
organic cleaning solvents, salts, builders, chelants, suds
suppressors, polymers, organic acids, odor control agents,
peroxides, buffers and mixtures thereof.
[0044] Generally, the ingredients of the liquid composition are
chosen based upon the desired end use for the premoistened wipe.
For example, if the wipe is a "baby wipe", the liquid composition
may be an emulsion, such as an oil-in-water type of emulsion having
as components an oily phase (in the form of an emollient), an
emulsifier or surfactant component, and an aqueous phase that
comprises further additives such as antimicrobial agents, soothing
agents, rheology modifiers, and mixtures thereof.
[0045] Properties of 100% Synthetic Nonwoven Wipes
[0046] The 100% synthetic nonwoven wipes of the present invention
exhibit various properties including, but not limited to,
absorptive capacity and CD bending moment. Additionally, the liquid
composition used to premoisten the nonwoven webs of the present
invention exhibit the property of surface tension.
[0047] I. Absorptive Capacity
[0048] The following method is suitable to measure the absorptive
capacity of any nonwoven web (when dry or wet) or finished wipe
(when dry or wet).
[0049] Materials/Equipment
[0050] 1. Sorption apparatus with computer. A suitable sorption
apparatus is manufactured by Machinetek Corporation of Fairfield,
Ohio U.S.A.
[0051] 2. Cylinder/Piston Apparatus. A suitable piston apparatus is
manufactured by Machinetek Corporation of Fairfield, Ohio
U.S.A.
[0052] 3. Balance which reads to four decimal places
[0053] 4. 6000 mL Erlenmeyer flask
[0054] Preparation of the Apparatus
[0055] The apparatus consists of a piston/cylinder apparatus and a
sorption apparatus. The piston/cylinder apparatus used for this
measurement has three parts. A cylinder is bored from a transparent
Lexan rod (or equivalent) and has an inner diameter of 6.00 cm
(area=28.27 cm.sup.2), with a wall thickness of approximately 5 mm
and a height of approximately 5 cm. The bottom of the cylinder is
faced with a No. 400 mesh stainless-steel screen cloth that is
biaxially stretched to tautness prior to attachment. The piston
consists of a Teflon.RTM. or Kel-F.RTM. "cup" and a stainless steel
weight. The cup is machined to fit into the cylinder within tight
tolerances. The cylindrical stainless steel weight is machined to
fit snugly within the cup and is fitted with a handle on the top.
The combined weight of the cup and stainless steel weight is 1390
g, which corresponds to 0.70 psi for an area of 28.27 cm.sup.2. A
second stainless steel weight with the combined weight of the cup
and weight being 596 g (0.30 psi) is also provided. Additionally,
the samples can be tested without use of the piston/cup/cylinder
assembly and new disk weights may be machined to obtain desired
confining pressures. For absorbent material mopping systems, an in
use pressure range of 0.07 to 0.10 psi is acceptable. For any
modeling purposes, representative confining pressures should be
determined on a case by case basis.
[0056] The components of the apparatus are sized such that the flow
rate of the solution through the apparatus under a 10 cm
hydrostatic head is at least 0.01 (g/cm.sup.2) per sec, where the
flow rate is normalized by the area of the fritted disc in the
apparatus. Factors particularly impacting system permeability may
include the permeability of the fritted disc and the inner
diameters of glass tubing and stopcocks.
[0057] The apparatus' reservoir is positioned on an analytical
balance that is at least accurate to .+-.0.01 g with a drift of
less than 0.1 g/hr. The balance is preferably interfaced to a
computer with software that can: (i) monitor balance weight change
at pre-set time intervals from the initiation of the absorptive
capacity test and (ii) be set to auto-initiate on a weight change
of 0.01-0.05 g, depending on balance sensitivity. The tube entering
the reservoir should not contact either the bottom of the reservoir
or its cover. The volume of fluid in the reservoir should be
sufficient (e.g. at least 40 mL) such that, during the procedure,
air is not drawn into the tube. The fluid level in the reservoir,
at the initiation of the procedure, should be about 2 mm below the
top surface of the fritted disc. This can be confirmed by placing a
small drop of fluid on the disc and gravimetrically monitoring its
slow flow back into the reservoir. This level should not change
significantly when the piston/cylinder apparatus is positioned on
the frit. The reservoir should have a sufficiently large diameter
(e.g., about 15 cm) so that withdrawal of fluid during the
procedure (e.g., about 40 mL) results in only a small change in the
fluid height (e.g., less than 3 mm).
[0058] Once preparation of the apparatus is complete, prepare for
each measurement by performing the following steps:
[0059] 1. Forward flush the fritted disc with the test fluid so
that it is filled with fresh fluid. Pour off the excess.
[0060] 2. Cover the funnel.
[0061] 3. Equilibrate the reservoir and the frit by opening the
connecting valves.
[0062] 4. Close all valves.
[0063] 5. Drain the frit for 5 minutes by opening the 3-way valve
to the drain.
[0064] 6. Close the drain valve.
[0065] The quantity of fluid that drains from the frit in this
procedure (called the frit correction weight) is measured by
conducting the procedure (see below) for a time period of 15
minutes without the piston/cylinder apparatus. Essentially all of
the fluid drained from the frit via this procedure is very quickly
reabsorbed by the frit when the procedure is initiated. Thus, it is
necessary to subtract this frit-correction weight from weights of
fluid removed from the reservoir during the procedure. The frit
correction is stable so this procedure may only be performed every
10-15 measurements.
[0066] Procedure
[0067] Before weighing the substrate, wipe the inner surface of the
cylinder and outer surface of the cup with isopropanol (if using
the cylinder assembly). Allow to air dry. If using the cylinder
assembly, now insert the substrate into the piston cup and add to
the cylinder. Place the cylinder or neat substrate onto the frit.
Slip the desired stainless steel weight (pre-calculated for desired
psi, nominally 0.04 psi) into the cup or directly onto the sample.
Place the funnel cover on the fritted funnel. Check the balance for
stability (i.e. the weight is constant, no change in the third
decimal place). Initiate the measurement by opening the 3-way valve
between the sample and the reservoir. With auto-initiation, data
collection starts immediately, as the fritted disc begins to
reabsorb fluid. Data is recorded for at least 3 minutes but should
be confirmed against the sample for a smooth leveling of the
absorption curve. Three sample replicates is minimally sufficient
as long as a smooth curve is obtained.
[0068] Reagents
[0069] 1. Distilled (DI) water.
[0070] 2. Triton.TM. X-100-PC, which is: commonly known as
(t-(t-Octylphenoxypolyethoxyethanol) that is peroxide and
carboxyl-free; and is obtainable from Sigma Aldrich, Saint Louis,
Mo. U.S.A.
[0071] Preparation of the Reagents
[0072] When using deionized (DI) water, no additional preparatory
steps are necessary. When using Triton.TM. X-100-PC, use the
following preparatory steps. First, measure out 1000 g of DI water
in a 1500 mL beaker. Using a scale with weight resolution of 0.01
g, measure out 1.0 g of Triton.TM. X-100-PC. Add the 1.0 g of
Triton.TM. X-100-PC to the 1000 g of DI water. Stir with a stir-bar
on a cold stir plate for approximately 5 minutes, or until the
Triton.TM. X-100-PC has visually dissolved in the water. Add to the
sorption apparatus.
[0073] Calculation of Absorptive Capacity
[0074] Absorptive capacity is reported in units of grams of liquid
composition per gram of the wipe substrate being tested. Absorptive
capacity at any time is determined as follows: 1 Absorptive
Capacity ( t ) = { W r ( t = 0 ) - W r ( t ) - W fc } W substrate ;
dry basis
[0075] Where t is the elapsed time from initiation, W.sub.r(t=0) is
the weight in grams of the reservoir prior to initiation,
W.sub.r(t) is the weight in grams of the reservoir at elapsed time
t, W.sub.fc is the frit correction weight in grams (measured
separately), and W.sub.substrate; dry basis is the dry weight in
grams of the substrate. Absorptive Capacity is typically reported
for times of 3 minutes after initiation. Additionally, if an
electronic data collection system is being used, a maximum
absorptive capacity can be obtained by substituting the maximum
weight in grams from the reservoir, W.sub.r(max) for W.sub.r(t).
This resolves the maximum absorptive capacity of the material: 2
Absorptive Capacity ( max ) = { W r ( t = 0 ) - W r ( max ) - W fc
} W substrate ; dry basis
[0076] Note that alternate sources of equivalent chemicals and
equipment may be used, provided they meet or exceed the
requirements necessary to preserve the accuracy and precision of
the method.
[0077] The wipes of the present invention may have an absorptive
capacity of greater than about 4 grams of liquid per wipe. The
wipes of the present invention may also have an absorptive capacity
of greater than about 6 grams of liquid per wipe. Additionally, the
wipes of the present invention may also have an absorptive capacity
of greater than about 8 grams of liquid per wipe.
[0078] II. Surface Tension of Liquid Composition
[0079] The following method is suitable to measure the surface
tension of the liquid compositions used to premoisten the wipes of
the present invention.
[0080] Materials/Equipment
[0081] 1. Kruss Processor Tensiometer K-12, manufactured by Kruss,
Charlotte, N.C. U.S.A.
[0082] 2. Small Sample Volume Platinum Plate
[0083] 3. Burner for Platinum Plate Cleaning
[0084] 4. Glass sample vessel for K12 Kruss Processor
Tensiometer
[0085] 5. Liquid composition or pure liquid to be tested
[0086] 6. High purity water
[0087] 7. Dish Detergent
[0088] 8. Isopropanol
[0089] Procedure
[0090] 1. Refer to the Kruss Owners Manual for Kruss Processor
Tensiometer.
[0091] 2. Clean the glass sample vessel with detergent, then lots
of high purity water, then rinse with isopropanol.
[0092] 3. Rinse out the glass sample vessel with the appropriate
liquid composition or pure liquid to be tested, then fill the glass
sample vessel 2/3 to 3/4 full. Place the glass sample vessel into
the silver jacket in the tensiometer.
[0093] 4. The first liquid composition to be tested is high purity
water (water measuring 70-74 dynes/cm is acceptable). If the high
purity water is out of the acceptable range refer to the Kruss
Owners Manual.
[0094] 5. After placing the liquid composition in the glass sample
vessel and into the silver jacket of the tensiometer, take the
platinum disc, rinse it with distilled water, then isopropanol.
Allow the disc to dry. Flame the disc red hot, not white. Allow the
disc to cool.
[0095] 6. Make sure the tensiometer balance is locked, then place
the platinum disc into the clip. Unlock the balance.
[0096] 7. On the printer/control pad enter 2 for Plate Method.
[0097] 8. Next Enter 1 for Surface Tension.
[0098] 9. Then Enter 1 for Single Measure.
[0099] 10. Then enter sample ID=date and whatever sample it is.
[0100] 11. Push CR on control pad.
[0101] 12. Move the liquid composition up close to the platinum
disc without touching the liquid composition.
[0102] 13. Push start.
[0103] 14. Record the surface tension result shown, which is
indicated in dynes/cm.
[0104] 15. Press CR to exit the program.
[0105] 16. Lock the balance. Lower the liquid composition away from
the platinum disc. Pull out the platinum disc.
[0106] 17. Clean the disc with distilled water, then isopropanal
and allow it to dry. Then flame the disc red hot and allow it to
cool.
[0107] 18. Clean the glass sample vessels with detergent, lots of
water, and then isopropanol.
[0108] The liquid composition used to premoisten the wipes of the
present invention may have a surface tension below about 35
dynes/cm. The liquid composition used to premoisten the wipes of
the present invention may have a surface tension below about 33
dynes/cm. Additionally, the liquid composition used to premoisten
the wipes of the present invention may have a surface tension below
about 30 dynes/cm.
[0109] III. Cross-Direction Bending Moment
[0110] The following method is suitable to measure the
cross-direction bending moment of the wipes of the present
invention.
[0111] Materials/Equipment
[0112] 1. The tester is a Kawabata Evaluation System for Fabrics,
KES-FB-2 AUTO-A, from Kato Tech Co., Ltd., Kyoto, Japan.
[0113] 2. Triton.TM. X-100-PC, which is: commonly known as
(t-(t-Octylphenoxypolyethoxyethanol) that is peroxide- and
carboxyl-free; and is obtainable from Sigma Aldrich, Saint Louis,
Mo. U.S.A.
[0114] Procedure
[0115] 1. Cut the wipe into 15 cm wide specimens.
[0116] 2. Saturate five specimens with 400% loading of a 0.1%
Triton.TM. X-100-PC solution. For example, a specimen weighing 2 g
will be saturated with 8 g of a 0.1% Triton.TM. X-100-PC
solution.
[0117] 3. Open the "Optional" measurement condition. Set
SENS="20.times.1" on the computer, set SENS="20" on the tester. Set
Kspan="SET"
[0118] 4. Set the check switch on "OSC" and confirm a deflection on
the voltmeter of +10V.
[0119] 5. Set the check switch on "BAL" and confirm a reading of 0V
on the voltmeter for each SENS setting. If necessary, adjust to 0V
with the apparatus screw "AC-Bal"
[0120] 6. Select ZERO and set the value to 0V on the digital
display with the "ZERO ADJ" screw (only for the sensitivity you
will be using).
[0121] 7. Select MES.
[0122] 8. Insert the specimen in the tray from the clamping unit,
making sure that it is centered properly and in the correct
orientation. The sensor light will come on when the specimen
reaches the proper position.
[0123] 9. Press the MEASURE button on the tester (the tester
automatically clamps the specimen). A light will blink when the
tester is ready to start the measurement.
[0124] 10. Start the measurement on the computer. The tester
automatically unclamps the specimen when measurement is
complete.
[0125] 11. Repeat steps 8 through 10 until 5 specimens have been
measured. Report the average bending moment per unit width,
expressed in (gf-cm.sup.2) per cm.
[0126] The wipes of the present invention may have a
cross-direction bending moment of less than about 0.10 (gf-cm.sup.2
) per cm. The wipes of the present invention may have a
cross-direction bending moment of less than about 0.09
(gf-cm.sup.2) per cm. Additionally, the wipes of the present
invention may have a cross-direction bending moment of less than
about 0.08 (gf-cm.sup.2) per cm.
[0127] Applications for 100% Synthetic Webs
[0128] The 100% synthetic webs of the present invention may be
useful in a wide variety of applications. For example, the webs may
be of use as a component of absorbent products such as disposable
diapers; feminine hygiene products; adult incontinence products;
medical products, particularly those that contact the human skin
such as surgical gowns and masks; industrial garments; filtration
media; and disposable dry or wet wipes, which may be
premoistened.
[0129] The 100% synthetic webs of the present invention may
comprise one or more layers of the wipes of the present invention.
The wipes may be premoistened with a liquid composition or
semi-liquid composition. In one embodiment of the present invention
the premoistened wipe may be a "baby wipe". A "baby wipe" is a wipe
that may be designed for use on a child by a care giver during the
changing of a soiled diaper. The wipe may be used to remove fecal
matter, dried urine or the like, from an infant. Alternatively the
"baby wipe" may be used to refresh a child in place of hand and/or
face washing or even to remove dirt, food, vomit, mucus and the
like, from the child and/or their clothing.
[0130] In another embodiment of the present invention, the wipe may
be an "adult wipe". That is the wipe is specially formulated for
use by an adult for refreshing, removing make-up, applying make-up
or lotions, food removal, cleaning, intimate use, etc.
[0131] In yet another embodiment, the wipe may be a "surface
cleaning wipe". Such a wipe may be designed for use on hard
surfaces such as floors, counter tops, sinks, walls, tiles, etc.
Hard surface cleaning wipes may be formulated for use on a variety
of surfaces, such as tile, ceramic, wood, porcelain, metal and
glass, including eyeglasses. Alternatively, they can be formulated
for use in a specific area, such as in the kitchen, bathroom or
motor vehicle. Wipes may also be used for cleaning or
stain-treating fabrics. "Surface cleaning wipes" may be moistened
prior to packaging, or may be dry wipes that are impregnated with
liquid compositions. The latter type of wipe may or may not be
moistened by the consumer prior to use.
EXAMPLES
[0132] The following examples are non-limiting examples of the
present invention. Each starting nonwoven is made into a wet wipe
by uniformly applying liquid compositions to the dry wipe. The wet
wipe is saturation loaded to approximately 4.0 grams of liquid
composition per gram of dry wipe. Different liquid compositions may
be used. One liquid composition is deionized water, which has a
surface tension of about 72 dynes/cm. A second liquid composition
is 0.1% Triton.TM. X-100-PC in deionized water, which has a surface
tension of about 31.5 dynes/cm. A third liquid composition is
0.0063% Triton.TM. X-100-PC in deionized water, which has a surface
tension of about 37.6 dynes/cm. A fourth liquid composition is
0.00313% Triton.TM. X-100-PC in deionized water, which has a
surface tension of about 42 dynes/cm. Non-limiting applications of
wipes described in Examples 1-7 may include, but are not limited
to, baby wipes, facial cleansing wipes, surface cleaning wipes,
polishing wipes, and personal hygiene wipes.
Example 1
[0133] S-Tex 194050HO, manufactured by BBA Fiberweb, Nashville,
Tenn. U.S.A., is used as the starting nonwoven. S-Tex 194050HO is a
50 gsm spunlaid nonwoven made from 100% polypropylene with a fiber
titre of 2.0 dtex (dtex is the unit denoting grams per 10,000
linear meters of fiber) and thermally bonded. No surface treatment
is added to the nonwoven.
[0134] The absorptive capacity, expressed in grams of liquid
composition per gram of wipe of S-Tex 194050HO for the two
different liquid compositions is summarized in the table below:
1 Absorptive Capacity Liquid [g liquid composition/g wipe]
Deionized Water 0.15 0.1% Triton .TM. X-100-PC in Deionized 8.9
Water
[0135] This example demonstrates the influence of the liquid on
absorptive capacity.
Example 2
[0136] Fibrella 7458, manufactured by Suominen Nonwovens, Nakkila,
Finland, is used as the starting nonwoven. Fibrella 7458 is a 58
gsm carded nonwoven made from 60% polypropylene staple fiber and
40% viscose fiber, each with a fiber titre of 1.5 dpf (dpf is the
unit denoting grams per 9,000 linear meters of fiber) and
hydroentangled. No surface treatment is added to the nonwoven.
[0137] The absorptive capacity of Fibrella 7458 for the two
different liquid compositions is summarized in the table below:
2 Absorptive Capacity Liquid [g liquid composition/g wipe]
Deionized Water 8.2 0.1% Triton .TM. X-100-PC in Deionized 8.5
Water
[0138] When compared with Example 1, this example demonstrates that
adding absorbent material to the nonwoven desensitizes the
influence of the liquid composition on absorptive capacity.
Example 3
[0139] Avspun.TM. Phobic, manufactured by Avgol Nonwoven
Industries, Holon, Israel, is used as the starting nonwoven.
Avspun.TM. Phobic is a 50 gsm spunlaid nonwoven made from 100%
polypropylene with a fibre titre of 1.4 dpf and hydroentangled. No
surface treatment is added to the nonwoven.
[0140] The absorptive capacity of Avspun.TM. Phobic for the two
different liquid compositions is summarized in the table below:
3 Absorptive Capacity Liquid [g liquid composition/g wipe]
Deionized Water 0.14 0.1% Triton .TM. X-100-PC in Deionized 12.8
Water
[0141] In conjunction with Example 1, this example demonstrates the
influence of the liquid on absorptive capacity regardless of the
method of nonwoven construction. This also illustrates that a
significant increase in total absorptive capacity can be achieved
by combining hydroentangled, continuous thermoplastic nonwovens and
a low surface tension fluid.
Example 4
[0142] Avspun.TM. philic, manufactured by Avgol Nonwoven
Industries, Holon, Israel, is used as the starting nonwoven.
Avspun.TM. philic is a 50 gsm spunlaid nonwoven made from 100%
polypropylene with a fiber titre of 1.4 dpf and hydroentangled. A
hydrophilic surface treatment is added to the nonwoven.
[0143] The absorptive capacity of Avspun.TM. philic with a low
surface tension liquid is presented in the table below:
4 Absorptive Capacity Liquid [g liquid composition/g wipe] 0.1%
Triton .TM. X-100-PC in Deionized 12.0 Water
[0144] This example illustrates that the high level of absorptive
capacity is maintained with a hydrophilic surface treatment of the
nonwoven.
Example 5
[0145] Avspun.TM. Lot# AVTI2489/2004 , manufactured by Avgol
Nonwoven Industries, Holon, Israel, is used as the starting
nonwoven. Avspun.TM. Lot# AVTI2489/2004 is a 45 gsm
spunlaid-meltblown-spunlaid nonwoven made from 100% polypropylene
with a spunlaid fiber titre of 1.6 dpf and hydroentangled. No
surface treatment is added to the nonwoven.
[0146] The absorptive capacity of Avspun.TM. Lot# AVTI2489/2004 for
three different liquid compositions is summarized in the table
below:
5 Absorptive Capacity Liquid [g liquid composition/g wipe]
Deionized Water .about.0 0.00313% Triton .TM. X-100-PC in 5.3
Deionized Water 0.0063% Triton .TM. X-100-PC in 5.6 Deionized Water
0.1% Triton .TM. X-100-PC in Deionized 14.4 Water
[0147] This example illustrates that the absorptive capacity is
dependent upon the surface tension of a liquid. Deionized water has
a surface tension of about 72 dynes/cm and the resulting absorptive
capacity is low. 0.00313% Triton.TM. X-100-PC solution has a
surface tension of about 42 dynes/cm and the resulting absorptive
capacity is 5.6 grams of liquid per gram of wipe. 0.0063%
Triton.TM. X-100-PC solution has a surface tension of about 37.6
dynes/cm and the resulting absorptive capacity is 5.3 grams of
liquid per gram of wipe. 0.1% Triton.TM. X-100-PC solution has a
surface tension of about 31.5 dynes/cm and the resulting absorptive
capacity is 14.4 grams of liquid per gram of wipe.
Example 6
[0148] A 30 gsm variant of the Avspun.TM. Phobic nonwoven cited in
example 3 is used as the starting nonwoven. The absorptive capacity
of this nonwoven with Deionized Water and with 0.1% Triton.TM.
X-100-PC in Deionized Water is the same as with the 50 gsm
variant.
Example 7
[0149] A 70 gsm variant of the Avspun Phobic.TM. nonwoven cited in
example 3 is used as the starting nonwoven. The absorptive capacity
of this nonwoven with Deionized Water and with 0.1% Triton.TM.
X-100-PC in Deionized Water is the same as with the 50 gsm
variant.
[0150] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *