U.S. patent application number 12/049724 was filed with the patent office on 2008-07-24 for soft, thick, non-linting nonwoven.
Invention is credited to Jonathan Paul Brennan.
Application Number | 20080176474 12/049724 |
Document ID | / |
Family ID | 22727502 |
Filed Date | 2008-07-24 |
United States Patent
Application |
20080176474 |
Kind Code |
A1 |
Brennan; Jonathan Paul |
July 24, 2008 |
SOFT, THICK, NON-LINTING NONWOVEN
Abstract
The nonwoven web 10 of the present invention is a layered
structure that takes advantage of the beneficial properties of
different types of fibers advantageously distributed in each layer.
In particular, the present invention is a multi-layer nonwoven web
suitable for use as a wet wipe, the web having a first fibrous
outer layer comprising from about 10% to about 60% conjugate fiber,
from about 10% to about 90% cellulosic fibers, a fibrous inner
layer bonded at discrete bond sites to the first outer layer in a
face to face relationship comprising from about 10% to about 60%
conjugate fiber, and from about 10% to about 65% cellulosic fibers.
A second fibrous outer layer, which can be the same composition as
the first outer layer, is bonded at discrete bond sites to the
inner layer in a face to face relationship. A method for forming
the web of the present invention is also disclosed.
Inventors: |
Brennan; Jonathan Paul;
(Cincinnati, OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY;INTELLECTUAL PROPERTY DIVISION - WEST BLDG.
WINTON HILL BUSINESS CENTER - BOX 412, 6250 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Family ID: |
22727502 |
Appl. No.: |
12/049724 |
Filed: |
March 17, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09824454 |
Apr 2, 2001 |
7358204 |
|
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12049724 |
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60196972 |
Apr 13, 2000 |
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Current U.S.
Class: |
442/381 |
Current CPC
Class: |
Y10T 442/66 20150401;
Y10T 442/69 20150401; Y10T 442/643 20150401; Y10T 442/671 20150401;
A47K 2010/3266 20130101; Y10T 442/668 20150401; Y10T 442/637
20150401; D04H 1/4374 20130101; D04H 1/541 20130101; D04H 1/559
20130101; B32B 5/26 20130101; Y10T 442/60 20150401; Y10T 442/67
20150401; Y10T 442/659 20150401 |
Class at
Publication: |
442/381 |
International
Class: |
B32B 5/26 20060101
B32B005/26 |
Claims
1. A multi-layer nonwoven web suitable for use as a wet wipe, the
web comprising: (a) a first fibrous outer layer comprising from
about 10% to about 60% conjugate fiber, from about 20% to about 65%
cellulosic fibers; (b) a fibrous inner layer comprising from about
10% to about 60% conjugate fiber, from about 10% to about 90%
cellulosic fibers, the inner layer bonded at discrete bond sites to
the first outer layer in a face to face relationship; and (c) a
second fibrous outer layer comprising from about 10% to about 60%
conjugate fiber, from about 20% to about 65% cellulosic fibers, the
second fibrous outer layer bonded at discrete bond sites to the
inner layer in a face to face relationship.
2. The nonwoven web of claim 1, wherein the first and second outer
layer comprise identical fiber compositions.
3. The nonwoven web of claim 1, wherein the first and second outer
layers together comprise from about 20% to about 80% of the total
basis weight of the web.
4. The nonwoven web of claim 1, wherein the first and second outer
layers each comprise from 20% to about 60% of the total basis
weight of the web.
5. The nonwoven web of claim 1, wherein the inner layer comprises
from about 33% to about 80% of the total basis weight of the
web.
6. The nonwoven web of claim 1, wherein the web is formed in the
absence of adhesive.
7. The nonwoven web of claim 1, wherein the first and second
fibrous layers are carded.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This patent application is a continuation of Nonprovisional
Utility patent application Ser. No. 09/824,454, filed Apr. 2, 2001,
which claims priority to Provisional Patent Application Ser. No.
60/196,972, filed Apr. 13, 2000, the substances of which are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention is related to nonwoven materials. In
particular, the present invention is related to soft, thick, and
non-linting nonwoven materials suitable for use as a substrate for
pre-moistened wipes.
BACKGROUND OF THE INVENTION
[0003] Nonwoven fabrics are desirable for use in a variety of
products such as bandaging materials, garments, disposable diapers,
and other personal hygiene products, including pre-moistened wipes.
Pre-moistened wipes are often packaged as discrete wipes in a stack
in a moisture proof container, and are often referred to as wet
wipes. Wet wipes are commonly used as baby wipes for the cleaning
of a baby's skin during a diaper change.
[0004] Nonwoven fabrics having high levels of strength, thickness,
drape, and softness are desirable for body-contacting articles,
such as linings for disposable diapers and wet wipes. However,
optimizing all the desirable properties is often not possible. For
example, often a balance of properties results in less than
desirable softness or strength levels. Wet wipes used as baby
wipes, for example, should be strong enough when wet to maintain
integrity in use, but soft enough to give a pleasing and
comfortable tactile sensation to the user(s). In addition they
should have fluid retention properties such that they remain wet
during storage, and sufficient thickness and porosity to be
effective in cleaning the soiled skin of a user.
[0005] Strength in a nonwoven fabric can be generated by a variety
of known methods. If thermoplastic fibers are used, strength can be
imparted by melting, either by through-air bonding or by hot roll
calendaring. Hydroentangling fibers in a spunlace operation and
adhesive bonding are also commonly used to bind fibers to increase
the strength of the nonwoven. However, these processes, while
increasing the strength of the nonwoven, generally detract from
other desirable properties. For example, thermal bonding is
effective at maintaining the thickness (bulk) of the nonwoven, but
maintaining a relatively soft product suitable for wet wipes
requires the use of relatively expensive conjugate fibers
throughout the nonwoven web. The use of conjugate fibers throughout
the nonwoven can also negatively affect the drape of the resulting
material.
[0006] Hydroentangling a fibrous structure generates strength, but
typically reduces the thickness of the material. Such a reduction
in thickness is undesirable in a wet wipe application. Due to the
nature of cleaning tasks for which wet wipes are used, consumers
prefer a wipe that has a minimum amount of apparent bulk, or
thickness associated with it. To increase the basis weight of the
starting material such that after hydroentangling the material
retains sufficient thickness to be used as a baby wipe would be
prohibitively expensive.
[0007] Adhesive bonding can be used to generate sufficient
strength, especially in a carded web. However, adhesive adds to the
expense of the resulting web, often costing more than the fibers of
the base web to which it is applied. Additionally, the presence of
adhesive can negatively impact the fragrance and preservative
ingredients in a wet wipe. Adhesive application systems also add
cost and complexity to a nonwoven manufacturing process, as well as
creating hygiene problems in the application equipment and other
equipment in the vicinity. Finally, adhesive can contribute to the
stiffness of the final nonwoven, which lowers the drape and
perceived softness of the material.
[0008] In addition to the attributes of relatively high strength,
drape, and softness, another property desirable in a nonwoven
suitable for a wet wipe is relatively low linting. Linting, or
pilling, occurs as fibers, or small bundles of fibers, are pulled
off, or otherwise released from, the surface of the nonwoven
substrate of the wet wipe. Linting results in fibers remaining on
the skin of the user, a highly undesirable condition for wet wipe
users. Linting can be controlled in much the same way that strength
is imparted. That is, to the extent that fibers of the nonwoven are
bonded to, or entangled with, one another, Tinting levels can be
controlled. Therefore, by increasing the level of adhesive in a
carded web, for example, Tinting can be decreased. However, as
mentioned above, the increased level of adhesive contributes to
greater stiffness and decreased levels of softness.
[0009] Accordingly, it would be desirable to have a soft, thick
nonwoven web suitable for use as a wet wipe, and having suitable
strength to maintain structural integrity during use.
[0010] Additionally, it would be desirable to have a soft, thick
nonwoven web suitable for use as a wet wipe for effective skin soil
cleaning.
[0011] Additionally, it would be desirable to have a thick and soft
nonwoven web suitable for use as a wet wipe exhibiting relatively
low levels of Tinting without the use of stiffness-increasing
additives, such as the addition of adhesive.
[0012] Additionally, it would be desirable to have a nonwoven web
suitable for a wet wipe that exhibits relatively high retention of
fluids such as aqueous fluids, and relatively high strength, but
remains soft to the skin, with sufficient thickness, texture and
porosity for effective skin soil cleaning.
[0013] Finally, it would be desirable to have a nonwoven web,
suitable for a wet wipe that can be made with a relatively high
strength, thickness and softness, without linting, and can be made
economically.
SUMMARY OF THE INVENTION
[0014] The nonwoven web 10 of the present invention is a layered
structure that takes advantage of the beneficial properties of
different types of fibers advantageously distributed in each layer.
In particular, the present invention is a multi-layer nonwoven web
suitable for use as a wet wipe, the web having a first fibrous
outer layer comprising from about 10% to about 60% conjugate fiber,
from about 20% to about 65% cellulosic fibers, a fibrous inner
layer bonded at discrete bond sites to the first outer layer in a
face to face relationship comprising from about 10% to about 60%
conjugate fiber, and from about 10% to about 90% cellulosic fibers.
A second fibrous outer layer, which can be the same composition as
the first outer layer, is bonded at discrete bond sites to the
inner layer in a face to face relationship. In a currently
preferred embodiment each layer also has a certain percentage of
multi-component, or conjugate fiber, such as bicomponent fiber.
[0015] A method for forming the web of the present invention is
also disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a simplified perspective view of one embodiment of
a nonwoven web of the present invention utilized as a wet wipe,
showing only a portion of the embossed area.
[0017] FIG. 2 is a schematic representation of an apparatus for
producing a nonwoven web of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The nonwoven web 10 of the present invention is a layered
structure that takes advantage of the beneficial properties of
different types of fibers advantageously distributed in each layer.
In particular, in a currently preferred embodiment, as shown in
FIG. 1, the nonwoven web of the present invention is at least a
three-layer structure having at least one relatively high basis
weight central layer 12 disposed between two relatively low basis
weight outer layers, 14 and 16. By "layer" as used herein is meant
a portion of a web that is formed as a discrete web apart from
other layers, for example by its own card in a carding operation,
prior to being joined to adjacent layers to form a unitary web. A
layer is made as a relatively homogeneous web, that is, the
constituent fibers are relatively evenly distributed within the
layer. Unless otherwise noted all percentages given herein are
weight percentages.
[0019] When formed by the method of the present invention, the
nonwoven web 10 exhibits a good balance of strength, extensibility,
thickness, drape, and softness, which are desirable for
body-contacting articles, such as linings for disposable diapers
and wet wipes. The web 10 also exhibits very low levels of linting,
and controlled stretch properties, which makes it particularly
useful as a substrate for pre-moistened wipes, otherwise known as
wet wipes. However, it is recognized that the nonwoven web 10 can
have other useful and beneficial uses as well. Therefore, a wet
wipe is taught herein as a preferred, but non-limiting use for the
nonwoven web 10.
[0020] In a currently preferred embodiment, the constituent outer
layers of the nonwoven web 10 are formed by carding. Carding is a
mechanical process whereby clumps of staple fibers are separated
into individual fibers and simultaneously made into a coherent web.
Carding is typically carried out on a machine that utilizes opposed
moving beds or surfaces of fine, angled, closely spaced teeth or
wires or their equivalent to pull and tease the clumps apart. The
teeth of the two opposing surfaces typically are inclined in
opposite directions and move at different speeds relative to each
other.
[0021] In a currently preferred embodiment, the constituent inner
layer of the nonwoven web 10 is formed by an air laying process.
Air laying is a process whereby air is used to separate, move, and
randomly deposit fibers from a forming head to form a coherent, and
largely isotropic web. Air laying equipment and processes are known
in the art, and include Kroyer or Dan Web devices (suitable for
wood pulp air laying, for example) and Rando webber devices
(suitable for staple fiber air laying, for example).
[0022] The nonwoven web 10 of the present invention and a method of
making are now described below with reference to FIGS. 1 and 2,
respectively.
The Nonwoven Web
[0023] In a currently preferred embodiment, the two outer layers 14
and 16 of nonwoven web 10 are identical, and each will be so
described in detail herein with reference to outer layer 14.
However, it is recognized that the two outer layers need not have
identical compositions, basis weights, or other material
properties.
[0024] The invention is described below as a three-layer web having
a single inner layer with two outer layers. However, it is
recognized that there can be more than one inner layer. For
example, instead of one airlaid forming head making the inner
layer, two or more heads can make up two or more inner layers.
However, the percentages for the various properties of the inner
layer below can apply to the inner layers as a whole, if more than
one inner layer is used between the outer layers.
[0025] In the currently preferred embodiment described herein, the
nonwoven web 10 is formed without the use of adhesive. That is, the
web is formed by a method that does not involve the application of
adhesive, and therefore the finished layered unitary web is
characterized by the absence of adhesive or an adhesive component.
Although in less preferred embodiments an adhesive can be used, in
a currently preferred embodiment the layers are held together to
form a unitary web only by fiber to fiber thermal bonds. FIG. 1
shows a portion of an embossed area 18 which can be a thermal bond
location.
[0026] In each layer of the nonwoven web 10 of the present
invention a combination of fiber types is utilized to optimize the
beneficial properties of each. For example, the outer layers can
have a certain percentage of cellulosic fibers to give the web a
soft, cloth-like feel; while the inner layer may have a different
percentage of the same or similar cellulosic fibers to provide for
improved absorbency and thickness. Each layer also has a certain
percentage of multi-component, or conjugate fiber, such as
bicomponent fiber, to provide for thermal bonding and softness
Other fibers, for instance polypropylene, polyester,
polypropylene-polyester conjugates and polyester-polyester
conjugates fibers may be added in each layer to achieve additional
properties such as thickness, softness and drape. In a currently
preferred embodiment, the nonwoven web 10 of the present invention
comprises the above-mentioned cellulosic and conjugate fibers in
pre-determined proportions, as described more fully below.
[0027] The outer layers 14 and 16 can each make up from about 10%
to about 40% of the total basis weight of nonwoven web 10. In one
preferred embodiment, each outer layer about 10% to about 30% of
the total basis weight of nonwoven web 10, and in a currently
preferred embodiment the two outer layers 14 and 16 are identical
and each comprise about 18% of the total basis weight of the
nonwoven web 10.
[0028] The inner layer 12 can make up from about 33% to about 80%
of the total basis weight of nonwoven web 10. In a currently
preferred embodiment, the inner layer 12 comprises about 62% of the
total basis weight of the nonwoven web 10.
[0029] The outer layers 14 and 16 should have sufficient quantity
of conjugate fibers to permit adequate fiber-to-fiber bonding
within the layers, and fiber-to-fiber bonding with fibers in the
central layer 12. Adequate fiber-to-fiber bonding is achieved when
loose surface fibers are "tied down" such that they are not easily
dislodged from the nonwoven web in the form of lint. Therefore,
each outer layer can have from about 10% to about 60% conjugate
fibers. In one preferred embodiment, each outer layer has about 25%
to about 60% conjugate fibers. Without being bound by theory, is
believed that 25% of conjugate fibers is the minimum amount
necessary to adequately tie down loose surface fibers for
consumer-acceptable low-linting wet wipe applications. In a
currently preferred embodiment the two outer layers 14 and 16 each
comprise about 50% conjugate fibers.
[0030] The inner layer 12 should also have sufficient quantity of
conjugate fibers to permit adequate fiber-to-fiber bonding,
particularly bonding with the fibers of the outer layers. Although
a structure of separate layers permits preferential distribution of
fiber types, it remains important that the constituent layers
perform as a unitary web when utilized as a wet wipe, particularly
in a baby wipe application. Delamination of the layers during use
detracts from the consumer benefits delivered from such a wet wipe.
Therefore, to avoid delamination of the layers, the inner layer can
have from about 10% to about 60% conjugate fibers. In one preferred
embodiment, the inner layer has about 15% to about 50% conjugate
fibers, and in a currently preferred embodiment the inner layer 12
comprises about 20% conjugate fibers which, without being bound by
theory, is believed to be the minimum amount necessary to maintain
structural integrity and to prevent delamination in
consumer-acceptable wet wipe applications.
[0031] The outer layers 14 and 16 should have sufficient quantity
of cellulosic fibers to give the nonwoven web 10 a soft, clothlike
feel. Each outer layer can have from about 30% to about 65%
cellulosic fibers. In one embodiment each outer layer has about 25%
to about 70% cellulosic fibers. Without being bound by theory, is
believed that 25% cellulosic fibers is the minimum amount that can
be used and still deliver a preferred clothlike feel in
consumer-acceptable wet wipe applications. In a currently preferred
embodiment the two outer layers 14 and 16 each comprise about 50%
cellulosic fibers.
[0032] The inner layer 12 can have a quantity of cellulosic fibers
sufficient to give the nonwoven web 10 adequate absorbency.
Especially when used as a wet wipe, each wipe should exhibit
sufficient absorbency to absorb and hold aqueous fluids or lotions
prior to use. Additionally, fluid, such as urine, should be
sufficiently absorbed so as to make the wipe is effective in
cleaning tasks associated with baby wipes. The inner layer can have
from about 10% to about 100% cellulosic fibers. The inner layer can
have about 25% to about 90% cellulosic fibers, and in a currently
preferred embodiment the inner layer 12 comprises about 80%
cellulosic fibers. In particular, using 80% cellulosic content in
the inner layer 12 together with the preferred percentages shown
above for the outer layers, gives a total substrate content of
about 68% cellulose, which has been found to be beneficial in baby
wipe applications. Without being bound by theory, about 40%
cellulosic fiber content is believed to be the minimum amount
necessary for adequate absorbency in consumer-acceptable wet wipe
applications. In one embodiment, the cellulosic content can be a
combination of low denier rayon fibers and fluff pulp fibers. A
preferred pulp fiber is Foley Fluff available from Buckeye
Technologies, Memphis, Tenn.
[0033] For each of the layers, the conjugate fibers can be of a
core/sheath design, and are preferably comprised of polypropylene
(as the core) and polyethylene (as the sheath). In a preferred
embodiment for the outer layers, the conjugate fibers can be from
about 20 mm to about 60 mm in length, and in a preferred embodiment
are about 40 mm in length. A preferred conjugate fiber is a 1.7
dtex, 40 mm fiber available as ES-C PHIL from ES-FiberVisions,
Covington, Ga. In a preferred embodiment for the inner layers, the
conjugate fibers can be from about 3 mm to about 12 mm in length,
and in a preferred embodiment are about 6 mm in length. A preferred
conjugate fiber is a 1.7 dtex, 6 mm fiber available as AL-Adhesion
C from ES-FiberVisions, Covington, Ga.
[0034] For the outer layers the cellulosic fibers can be rayon, and
in a preferred embodiment are fibers low denier rayon fibers having
a length of between about 20 mm and about 60 mm in length. In a
preferred embodiment, the rayon is 1.5 denier fiber having an
average length of about 40 mm. A preferred rayon fiber is available
as type 18453, available from Acordis Cellulosic Fibers, Axis,
Ala.
Method for Making
[0035] FIG. 2 shows a schematic representation of an apparatus for
use in a preferred method of making the nonwoven web 10 of the
present invention. As shown in FIG. 2, the method is a combination
a of carding and airlaying processes, with subsequent through-air
bonding and calendaring of the multi-layer substrate. Without being
bound by theory, it is believed that the sequence of steps in the
method described herein with reference to FIG. 2 is important to
achieving the beneficial web properties, as described below.
[0036] An apparatus, generally designated at 20, comprises a
carding apparatus having at least two cards designated at 22 and 26
and one airlay forming head 24. Each component forms a discrete
web. Any of these discrete webs could also be supplied as
pre-bonded nonwoven roll goods. The first card 22 forms a carded
web corresponding to layer 16 as depicted in FIG. 1. Subsequently,
the airlay forming head forms a web, layer 12, on top of layer 16.
Finally, card 26 forms a carded web, layer 14, which is transferred
on top of layer 12.
[0037] Each carded web can be formed by carding methods known in
the art, and deposited by known methods, such as by doffing, onto a
forming belt or screen 28. Each airlaid web can be formed by
airlaying methods known in the art, and deposited by known methods
onto a forming belt or screen 28. As all three layers are formed on
forming screen 28, forming screen 28 is moved in the machine
direction MD by rolls 29. In this way, nonwoven web 10 can be
formed in a continuous process. The direction of forming is
referred to as the machine direction MD, while the width of the web
is measured in the cross direction CD.
[0038] The fiber composition of the fiber supply for each card and
airlaid forming head can be predetermined, formulated and/or
adjusted by methods known in the art for supplying mixed fiber
cards and airlaying heads. In a preferred process, and to produce a
web having properties optimally suited for use as a wet wipe, the
fiber compositions can be prepared as follows. For both cards 22
and 26, the preferred fiber composition is 50% Type 18453 rayon and
50% ES-C PHIL PP/PE conjugate fiber, each of which are described
above. For the airlay forming head 24, the preferred fiber
composition is 80% Foley Fluff and 20% AL Adhesion C conjugate
fiber, each of which are described above.
[0039] After all three layers of the carded nonwoven web are
deposited in a layered relationship, the deposited fibers are moved
by forming screen 28 to a thermal treatment apparatus 30. Thermal
treatment apparatus 30 can incorporate any of known methods for
subjecting the layered web to sufficiently elevated temperatures so
as to effect thermoplastic melting of the polyethylene component of
the constituent conjugate fibers. Upon cooling, portions of the
conjugate fibers remain melt-bonded to portions of adjacent
conjugate fibers, thereby forming the three layers into a unitary
web having substantially uniform distribution of layer to layer
bond sites.
[0040] Fiber to fiber thermal bonds are preferably made by a
through-air dryer comprising a through-air drying drum 32 which the
carded web is transferred onto for a predetermined dwell time. The
advantage of using a through-air dryer is that the web is heated
sufficiently with little or no compression. In this manner, the
constituent layers of the web can be bonded together due to the
conjugate fiber-to-conjugate fiber bonding, without unnecessary
compression of calendaring rollers, for example. Without wishing to
be bound by theory, it is believed that the through-air bonding
step tends to "set" the loft of the nonwoven by effecting bonding
without unnecessary compression. This "loft setting" produces a
bulkier sheet for better thickness in the end product. By using the
composition percentages described above, the thickness of the
finished product is believed preferred by consumers using the web
as a wet wipe.
[0041] The through-air thermal bonding process can be carried out
by methods known in the art for through-air drying webs, including
paper webs. In general, the nonwoven web is guided and removed from
screen 28 and placed in contact with a rotating perforated drying
drum 32. Hot air of sufficient temperature is forced out of the
perforated drying drum 32 and through the nonwoven web being
thermally treated. The air temperature, air volume, and machine
direction line speed of production can be adjusted to ensure
sufficient dwell time for adequate fiber-to-fiber bonding. The
actual time, temperature, and line speed can be varied as
appropriate, and is not considered to be critical.
[0042] After being thermally bonded, the layered, bonded web is
then continues for further processing to a calendaring apparatus
40. Calendaring apparatus 40 preferably comprises thermal embossing
means to impart an embossed pattern of compressed regions onto the
layered, bonded web. The embossing means can include standard
embossing patterns and equipment as are known in the art.
[0043] By embossing the layered, bonded nonwoven web, the nonwoven
web can gain better aesthetics, particularly for use as a wet wipe.
However, besides better aesthetics, other beneficial physical
characteristics are imparted to the nonwoven web by calendaring.
For example, by calendaring the web at sufficiently elevated
temperatures additional thermal bonding is achieved in the
compressed regions, thereby giving better surface fiber bonding.
This surface fiber bonding "ties down" loose fiber, resulting in
reduced Tinting of the finished web. Additionally the thermal
bonding of the calendaring operation increases the strength of the
nonwoven web 10, especially when used in a wet wipe application.
The added embossing also produces a web having a topography that
exhibits sufficient texture and porosity for effective skin soil
cleaning Finally, the thermal emboss contributes to reducing the
available cross-direction CD stretch of the finished web. Excessive
CD stretch is often a characteristic of carded webs, and is
generally undesirable in a wet wipe. By reducing CD stretch, the
stretch properties of the web are more uniform, and more suited for
use as a wet wipe.
[0044] The thermal embossing can be carried out by suitable methods
known in the art. In one embodiment satisfactory results were
produced by setting the calendaring apparatus 40 temperatures at
145 degrees Centigrade on the pattern roll 42, and on the anvil
roll 44. A nip pressure of about 264 pound per linear inch produces
satisfactory results for the preferred web described above, having
three layers and a total basis weight of 64 grams per square meter
(gsm).
[0045] The layered, bonded, and calendared web can then be wound as
roll stock on a parent roll 50 for storage or further
processing.
[0046] While particular embodiments and/or individual features 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. Further, it should be apparent that all
combinations of such embodiments and features are possible and can
result in preferred executions of the invention. Therefore, the
appended claims are intended to cover all such changes and
modifications that are within the scope of this invention.
* * * * *