Note: Descriptions are shown in the official language in which they were submitted.
- 214238
PATENT
A STACK OF MOIST WIPES AND METHOD OF PRODUCING THE SAME
Back4round of the Invention
Field of the Invention
The present invention relates to moist wipes and a method of
producing the same. The invention particularly concerns a stack of
moist wipes which has a reduced migration of liquid between the top
and bottom of the stack.
Description of the Related Art
Wet wipes are well known commercial consumer products which have been
available in many forms. Perhaps the most common form has been a
stack of moistened individual folded sheets which have been packaged
in a plastic container. In addition, the wet wipes have been in the
form of continuous webs of material having perforations to separate
individual sheets which are moistened, wound into rolls and packaged
in plastic containers. Such wipes have been used for baby wipes,
hand wipes, household cleaning wipes, industrial wipes and the like.
The wet wipes have been made from a variety of materials which are
saturated with a suitable wiping solution.
The conventional packages and stacks of wet wipes, such as those
described above, have not been sufficiently satisfactory. For
example, the amount of wiping solution has varied from sheet to sheet
in an undesirable manner. The wiping solution in stacks of wipes
produced predominantly from airlaid cellulosic fibers has had a
tendency to migrate from the top to the bottom of the stack of wipes
due to gravity. Frequently, a pool of solution has formed on the
bottom of the container. This, of course, is wasted solution. When
other materials, such as meltblown polyolefin webs, have been used
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for wet wipes, the wet wipes have exhibited a tendency to allow the
solution to migrate towards the top of the stack of wipes through
capillary action. In such stacks of wipes, the wipes on the bottom
of the stack may have a much lower amount of solution than the wipes
on the top of the stack. The problem of solution migration has been
particularly acute as the number of wipes in a stack has increased
and when the wipes have been stacked for a period of time. For
example, solution migration has been a problem in packages with a
large number of wipes which are intended to be used to refill
conventional packages more than once. The problem of solution
migration is also more acute when the container has been repeatedly
opened allowing the wipes on the top of the stack to partially dry.
The problem of solution migration has undesirably varied the amount
of solution from wipe to wipe within the stack of wipes. Thus, the
wipes at the top of conventionally packaged stacks of wet wipes have
had either a very high or a very low amount of solution relative to
the wipes at the bottom of the stack.
Summary of the Invention
In response to the discussed difficulties and problems encountered in
the prior art, a new method for reducing the solution migration in a
stack of moist wipes has been discovered.
In one aspect, the present invention can provide a stack of moist
wipes which has a top and a bottom. The stack of moist wipes
includes a plurality of sheets which contain a liquid and which~are
arranged in a stacked configuration. At least one moisture barrier
is placed in the stack of moist wipes to reduce migration of the
liquid between the top and the bottom of the stack. In a particular
aspect, the stack of moist wipes includes from about 40 to about 320
sheets. The moisture barrier has a permeability which is less than a
permeability of each of the sheets. In a particular aspect, the
moisture barrier is substantially liquid impermeable. The moisture
barrier selectively divides the stack of moist wipes forming at least
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CA 02142385 2004-03-08
two substacks of moist wipes. Each of said substacks of moist wipes
contains substantially the same amount of liquid for at least 21
days.
In another aspect, the present invention can provide a package of
moist wipes. The package includes a container which defines an
interior and is capable of being sealingly closed. A plurality of
sheets are disposed in the interior of the container. The sheets
contain a liquid and are arranged in a stacked configuration to form
a stack of moist wipes. The stack of moist wipes has a top and a
bottom. At least one moisture barrier is placed in the stack of
moist wipes to reduce migration of the liquid between the top and the
bottom of the stack. In a particular aspect, the container includes
a flexible bag which has a resealable closure along a top of the bag.
In a further aspect, the present invention can provide a method for
reducing migration of a liquid within a stack of moist wipes. A
plurality of sheets which contain the liquid are provided in a
stacked configuration to form a stack of moist wipes. The stack of
moist wipes has a top and a bottom. At least one moisture barrier is
placed in the stack of moist wipes to reduce migration of the liquid
between the top and the bottom of the stack. The moisture barrier
may be placed between selected adjacent sheets to substantially
eliminate migration of the liquid between the adjacent sheets.
In a further aspect, the stack and/or package of moist wipes has at
least one moisture barrier with a barrier width which is greater than a
width of said sheets and a barrier length which is greater than a length
of said sheets and wherein the barrier width is in the range of about
110% to about 150% of the width of said sheets and the barrier length
is in the range of about 105% to about 150% of the length of said
sheets.
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CA 02142385 2004-03-08
The present invention, in its various aspects, can advantageously
provide a package and stack of moist wipes which, when compared-to
conventional packages and stacks of wet wipes, has a reduced
migration of liquid between the top and bottom of the stack. Thus,
the package of moist wipes, stack of moist wipes and method of the
present invention provide wipes which are not oversaturated or dried
out even after standing for a long period of time and after repeated
exposure to ambient air. Such a package and stack of moist wipes can
advantageously be used to refill conventional packages a multiple of
times.
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Brief Description of the Drawings
The present invention will be more fully understood and further
advantages will become apparent when reference is made to the
following detailed description of the invention and the accompanying
drawings. The drawings are merely representative and are not
intended to limit the scope of the claims.
Fig. 1 representatively shows a perspective view of a stack of moist
wipes of the present invention;
Fig. 2 representatively shows a perspective view of a package of the
present invention;
Fig. 3 representatively shows a cross-sectional view of the package
of Fig. 2 taken along line 3--3;
Fig. 4 representatively shows a comparison of the data obtained in
Example 1 with the data from Comparative Example 1;
Fig. 5 representatively shows a comparison of the data obtained in
Example 2 with the data from Comparative Example 1;
Fig. 6 representatively shows a comparison of the data obtained in
Example 3 with the data from Comparative Example 1;
Fig. 7 representatively shows a comparison of the data obtained in
Example 4 with the data from Comparative Example I; and
Fig. 8 representatively shows a comparison of the data obtained in
Example 5 with the data from Comparative Example 1.
Detailed Description of the Invention
The present invention provides a stack of moist wipes which has a
reduced migration of liquid between the top and bottom of the stack,
and a method of producing the same. In addition, the present
invention provides a stack of moist wipes contained within a package.
In a specific embodiment, the stack of moist wipes of the present
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invention can be contained in a resealable plastic bag and used to
refill a conventional plastic container one or more times after the
original stack of moist wipes has been used by the consumer. Such
package and stack of moist wipes can be used for baby wipes, hand
wipes, face wipes, cosmetic wipes, household wipes, industrial wipes
and the like.
As used herein, the term "stack" and "stacked configuration" refers
to any collection of sheets wherein there is a plurality of
surface-to-surface interfaces between the sheets.
As used herein, the term "machine direction" refers to the direction
along which the web of material, which is used to provide the stack
of moist wipes of the present invention, is intended to move at any
particular location.
As used herein, the term "permeability" refers to the permeability of
the sample material as determined by using the method taught by
Miller, et al. in the Textile Research Journal, Vol. 48 at
pages 150-155 (1978), wherein the viscous drag of several different
materials is determined. The permeability of the material is
determined using the following equation ("Darcy's Law"):
q = k(PB - P~)/yx,
wherein
q = linear velocity of the piston
y = viscosity of the liquid
x = thickness of the sample
(PB - P~) = viscous drag of the material
k = saturated permeability of the material
As representatively illustrated in Fig. 1, the present invention
provides a stack of moist wipes, as generally indicated at 10. The
stack of moist wipes 10 includes a plurality of sheets 12 which are
arranged in a stacked configuration 18. The stack of moist wipes 10
has a top 20 and a bottom 22 and can comprise any suitable number of
individual sheets 12 with each individual sheet 12 providing a moist
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wipe. In a particular aspect, the stack of moist wipes 10 includes
from about 40 to about 320 sheets, desirably from about 80 to about
240 sheets and more desirably from about 140 to about 180 sheets.
The sheets 12 may or may not be folded as they are arranged in the
stacked configuration 18. Such folded configurations are well known
to those skilled in the art and include, for example, z-folded and
quarter-folded configurations. If the sheets 12 are folded, each
sheet 12 may be interfolded with the sheets immediately above and
below in the stacked configuration 18. As representatively
illustrated in Fig. 1, the sheets 12 have a width 14 and a length 16.
If the sheets 12 are folded prior to being arranged in the stacked
configuration 18, the width 14 and length 16 refers to the as-folded
width and length of the folded sheet. The sheets 12 may have any
suitable width 14 and length 16. For example, the sheets may have a
width 14 of from about 2 to about 40 centimeters and desirably from
about 7 to about 14 centimeters and a length 16 of from about 2 to
about 80 centimeters and desirably from about 10 to about 25
centimeters.
Materials suitable for the plurality of sheets 12 are well known to
those skilled in the art. The sheets 12 can be made from any
material suitable for use as a moist wipe, including meltblown,
coform, air-laid, bonded-carded web materials, and the like and can
comprise synthetic or natural fibers or combinations thereof. The
sheets 12 may have a basis weight of from about 25 to about 120 and
desirably from about 40 to about 90 grams per square meter. In.a
particular aspect, the sheets 12 are a coform basesheet of polymeric
microfibers and cellulosic fibers having a basis weight of from about
60 to about 80 and desirably about 75 grams per square meter. Such
coform basesheets are manufactured generally as described in U.S.
Patent No. 4,100,324 to Anderson et al. dated July 11, 1 J78. Typically, such
coform
basesheets comprise a gas-formed matrix of thermoplastic polymeric meltblown
microfibers, such as, for example. polypropylene microfibers, and cellulosic
fibers,
such as, for example, wood pulp fibers. The relative percentages of the
polymeric
microfibers and cellulosic
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fibers in the coform basesheet can vary over a wide range depending
on the desired characteristics of the moist wipes. For example, the
coform basesheet may comprise from about 20 to about 100, desirably
from about 20 to about 60, and more desirably from about 30 to about
40 weight percent of polymeric microfibers based on the dry weight of
the coform basesheet being used to provide the moist wipes.
Alternatively, the sheets 12 can be made from a meltblown sheet of
polymeric microfibers having a basis weight of from about 25 to about
120 grams per square meter. Typically, the sheets 12 are liquid
permeable. For example, each sheet 12 may have a permeability of
about 100 darcies.
The sheets 12 of the stack of moist wipes 10 of the different aspects
of the present invention contain a liquid which can be any solution
which can be absorbed into the sheets 12. The liquid contained
within the stack of moist wipes 10 may include any suitable
components which provide the desired wiping properties. For example,
the components may include water, emollients, surfactants,
preservatives, chelating agents, pH buffers or combinations thereof.
The amount of liquid contained within each individual sheet 12 or
wipe may vary depending upon the type of material being used to
provide the sheets 12, the type of liquid being used, the type of
container being used to store the stack of moist wipes 10, and the
desired end use of the moist wipes. Generally, each sheet 12 can
contain from about 150 to about 600 and desirably from about 250 to
about 450 weight percent liquid based on the dry weight of the sheet
or wipe. In a particular aspect wherein the sheets 12 are made. from
a coform material comprising from about 30 to about 40 weight percent
polymeric microfibers based on the dry weight of the sheet, the
amount of liquid contained within each individual sheet 12 or wipe is
from about 300 to about 400 and desirably about 340 weight percent
based on the dry weight of the sheet or wipe. Accordingly, the stack
of moist wipes 10, as representatively illustrated in Fig. 1, may
include from about 150 to about 600, desirably from about 250 to
about 450, and more desirably from about 300 to about 400 weight
percent of the liquid based on the dry weight of the sheets 12. If
the amount of liquid is less than the above-identified range, the
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wipe may be too dry and may not adequately perform. If the amount of
liquid is greater than the above-identified range, the wipe may be
oversaturated and soggy and the liquid may pool in the bottom of the
container.
As representatively illustrated in Fig. 1, at least one moisture
barrier 24 is placed in the stack of moist wipes 10 to reduce
migration of the liquid between the top 20 and the bottom 22 of the
stack 10. In one aspect, the moisture barrier 24 may be placed in
the stack of moist wipes 10 between selected adjacent sheets 12. In
such a configuration, the moisture barrier 24 may substantially
reduce or eliminate the migration of liquid between the adjacent
sheets 12. The moisture barrier 24 may also be contained within or
surrounded by a single folded sheet 12 within the stack of moist
wipes 10.
The moisture barrier 24 can be made from any suitable material which
may or may not be liquid impermeable. Suitable materials for the
moisture barrier 24 include polymeric materials such as polyolefins
which include polypropylene and polyethylene, cellulosic or nonwoven
materials which may be at least partially hydrophobic, and the like.
Such materials may also be treated such as, for example, with a
surfactant. In one aspect, the moisture barrier 24 may be made from
a polymeric material which substantially reduces or eliminates the
migration of liquid between the adjacent sheets. For example, the
moisture barrier 24 may include a polyethylene film having a
thickness of from about 0.1 to about 5 mils and desirably from about
0.25 to about 1.0 mils. Such polyethylene materials are available
from Consolidated Thermoplastics Co., a company having offices in
Chippewa Falls, Wisconsin. The materials used to provide the
moisture barrier 24 may also be embossed with any suitable pattern.
In another aspect, the moisture barrier 24 may be a multilayer
material comprising at least one layer of a nonwoven material, such
as the coform material used to provide the sheets 12 and at least one
barrier layer, such as a polyethylene film layer. For example, a
_g_
polyethylene barrier layer may be disposed between two coform layers.
Thus, such a moisture barrier 24 could function both as a moist wipe
and as a means to reduce migration of liquid in the stack.
In a particular aspect, the moisture barrier 24 may substantially
reduce migration of liquid in one direction while not substantially
inhibiting migration of liquid in the opposite direction. For
example, the moisture barrier 24 may be made from a material which,
when placed in a certain orientation in the stack of moist wipes 10,
reduces or eliminates the migration of liquid from the top 20 to the
bottom 22 of the stack of moist wipes 10 while not substantially
inhibiting the migwation of liquid from the bottom 22 to the top 20
of the stack of moist wipes 10.
The moisture barrier 24 substantially reduces migration of the liquid
between the top 20 and bottom 22 of the stack of moist wipes 10 by
inhibiting the flow of the liquid between the sheets 12 directly
above and below the moisture barrier 24. The amount of liquid which
flows through the moisture barrier 24 should be less than the amount
of liquid which flows through the sheets 12 under similar conditions.
Thus, the moisture barrier 24 has a permeability which is less than a
permeability of each of the sheets 12. In a particular aspect, the
moisture barrier 24 is substantially liquid impermeable. However,
the moisture barrier 24 may be liquid permeable to a certain degree
without adversely affecting the different aspects of the present
invention. For example, the moisture barrier 24 may have a
permeability which is less than 95 percent, desirably from about 0 to
about 75 percent, and more desirably from about 0 to about 25 percent
of the permeability of the sheets 12 for improved performance.
Moreover, the moisture barrier 24 may have a permeability of less
than 100 darcies, desirably less than 50 darcies, more desirably less
than 25 darcies and most desirably less than 10 darcies for improved
performance.
Each moisture barrier 24, as representatively illustrated in Fig. 1,
has a barrier width 26 and a barrier length 28. The barrier width 26
and barrier length 28 may be any suitable dimension which provides
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the desired reduction in migration of liquid. In a particular
aspect, the barrier width 26 is greater than the width 14 of the
sheets 12 and the barrier length 28 is greater than the length 16 of
the sheets 12. For example, the barrier width 26 may be at least
about 100 percent and desirably from about 110 to about 150 percent
of the width 14 of the sheets 12. In addition, the barrier length 28
may be at least about 100 percent and desirably from about 105 to
about 150 percent of the length 16 of the sheets 12. For example,
the moisture barrier 24 may have a barrier width 26 of about 12.1
centimeters and a barrier length 28 of about 21.6 centimeters. If
more than one stack of moist wipes 10 is to be included in the final
package, the barrier width 26 and barrier length 28 of the moisture
barrier 24 may be suitably controlled such that the moisture barrier
reduces the migration of liquid within each stack of moist wipes 10
in the package.
Each moisture barrier 24 selectively divides the stack of moist
wipes 10 forming at least two substacks of moist wipes, 30 and 32. A
suitable number of moisture barriers 24, such as, for example, from 1
to about 8 moisture barriers, may be placed in the stack of moist
wipes 10 at selected locations between the top 20 and bottom 22 of
the stack depending on the desired reduction in the migration of the
liquid. The moisture barriers 24 may also serve as a counter to
indicate the desired number of sheets 12 to withdraw.
The moisture barriers 24 may be placed at selected locations between
adjacent sheets between the top 20 and bottom 22 of the stack of
moist wipes 10. For example, a moisture barrier 24 may be
selectively disposed between every eighth, sixteenth, fortieth,
eightieth, or similar number of sheets 12 thereby dividing the stack
of moist wipes 10 into two or more substacks of moist wipes. Each
substack may have the same or different numbers of sheets 12. In a
particular aspect of the invention as representatively illustrated in
Fig. 1, one moisture barrier 24 is disposed between the eightieth and
eighty-first sheets in the stack of moist wipes 10 which includes 160
sheets thereby selectively dividing the stack of moist wipes 10 into
two substacks of moist wipes, 30 and 32, each of which includes
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eighty sheets 12. In such a configuration, substack 30 includes the
top one-half of the stack of moist wipes 10 while substack 32
includes the bottom one-half of the stack of moist wipes 10. Thus,
the moisture barrier may indicate two eighty-count substacks of wipes
which could be used to refill a conventional 80-count package.
The moisture barrier 24 reduces migration of liquid between the
top 20 and bottom 22 of the stack of moist wipes such that each of
the substacks of moist wipes, such as 30 and 32 as representatively
illustrated in Fig. 1, contain substantially the same amount of
liquid after being allowed to stand for a period of time. The amount
of the liquid within each of the substacks of moist wipes may depend
upon the number of sheets 12 in each substack, the number of moisture
barriers 24 being used and the corresponding number of substacks, and
the total amount of liquid added to the sheets 12.
In a particular aspect of the invention wherein each of the substacks
has the same number of sheets 12, each of the substacks of moist
wipes, such as substack 30, may contain at least about 75 percent,
desirably from about 80 to about 120 percent and more desirably from
about 95 to about 105 percent of the amount of liquid contained in
each of the other substacks of moist wipes, such as substack 32,
after being allowed to stand for 21 days. Each of the substacks of
moist wipes, such as 30 and 32 as representatively illustrated in
Fig. 1, includes a top sheet 34 and a bottom sheet 36. In a
particular aspect wherein each substack has the same number of
sheets 12, the moisture barrier 24 reduces migration of liquid
between the top 20 and bottom 22 of the stack of moist wipes 10 such
that the top sheets 34 of each of the substacks of moist wipes have
the same amount of liquid after being allowed to stand for a period
of time. For example, each top sheet 34 of each of the substacks of
moist wipes, such as substack 30, may contain at least about 75
percent, desirably from about 80 to about 120 percent and more
desirably from about 95 to about 105 percent of the amount of liquid
contained in each of the other top sheets 34 after being allowed to
stand for a period of 21 days. Moreover, in such a configuration,
the moisture barrier 24 reduces migration of liquid between the
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top 20 and bottom 22 of the stack of moist wipes 10 such that the
bottom sheets 36 of each of the substacks contain substantially the
same amount of liquid after being allowed to stand for a period of
time. For example, each bottom sheet 36 of each of the substacks of
moist wipes, such as substack 30, may contain at least about 75
percent, desirably from about 80 to about 120 percent and more
desirably from about 95 to about 105 percent of the amount of liquid
contained in each of the other bottom sheets 36 after being allowed
to stand for a period of 21 days.
Figs. 4-8 representatively illustrate the effects of adding at least
one moisture barrier having a variable size to a 160-count stack of
moist wipes as outlined in the Examples. The plots illustrate that
the moisture barrier of the different aspects of the present
invention effectively reduces the migration of liquid between the top
and bottom of a stack of moist wipes when compared to stacks of moist
wipes with no moisture barrier. In particular, the plots illustrate
that the moisture barrier substantially reduces or eliminates
migration of the liquid between the sheets adjacent to and on top of
and underneath the moisture barrier. The plots and Examples also
illustrate that a moisture barrier which is larger than the
individual sheets is more effective at reducing the migration than
smaller moisture barriers.
The stack of moist wipes 10, as representatively illustrated in
Fig. 1, of the different aspects of the present invention may be
manufactured using several different processes well known to those
skilled in the art. The particular method and sequence of steps
described herein is not a limitation to the present invention, but is
disclosed only as one method of producing a stack of moist wipes.
Initially a supply roll of the material being converted into the
sheets 12 is unwound. The web of material is saturated or otherwise
impregnated with a liquid, such as those described above, by any
suitable means such as spraying, dipping, or the like as are well
known to those skilled in the art. In a particular aspect, the web
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of material is passed over several perforated tubes which exude the
liquid into the material. The add-on amount of liquid can be any
amount which produces the desired stack of moist wipes 10.
The web of material is slit in the machine direction into multiple
ribbons, each of which may be folded into the type of fold desired
for each individual sheet 12. For example, the web of material can
be slit into eight ribbons and folded into a z-folded configuration.
Each z-folded ribbon is then combined, one ribbon on top of the
other, with the other seven z-folded ribbons from the same web of
material to form a continuous "sausage." The sausage is then cut
into "clips" of eight sheets apiece and the clips of sheets are
combined in a stacked configuration to form at least one stack of
moist wipes 10 as representatively illustrated in Fig. 1. The number
of clips in a stack depends on the desired number of stacks and the
number of sheets 12 in the final package. For example, for a
160-count package having one stack, twenty clips of eight sheets
apiece would be required to form a single stack of 160 moist wipes.
Before arranging the clips of sheets in the stacked configuration 18,
from 1 to about 8 moisture barriers 24, as representatively
illustrated in Fig. 1, are placed in the stack of moist wipes 10 at
selected locations between the top 20 and bottom 22 of the stack.
For example, the moisture barriers 24 may be placed between adjacent
sheets at each of the selected locations. The moisture barriers 24
substantially eliminate migration of liquid between the adjacent
sheets. For example, moisture barriers 24 may be placed between each
clip of sheets, between every other clip of sheets, or between any
multiple of clips of sheets. Thus, moisture barriers 24 may be
placed between every eighth, sixteenth, fortieth or eightieth sheet
or between any other adjacent sheets in the stack of moist wipes 10.
In a particular aspect as representatively illustrated in Fig. 1, one
moisture barrier 24 is placed between the eightieth and eighty-first
sheet of a 160-count stack of moist wipes to selectively divide the
stack of moist wipes 10 into a top one-half and a bottom one-half.
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After the stack of moist wipes 10, as representatively illustrated in
Fig. 1, is properly configured, at least one stack of moist wipes is
placed in the interior of a container, such as a plastic bag, to
provide a package of moist wipes. As representatively illustrated in
Figs. 2 and 3, the package of moist wipes, as generally indicated at
50, includes a container 52 which provides a substantially
hermetically sealed environment for at least one stack of moist
wipes 10 to minimize the escape of any liquid therefrom. For
example, the container 52 may include an outer bag 54 having a front
panel 56, a back panel 58 and a bottom gusset 60. The front panel 56
and back panel 58 are joined together along their respective side
edges using suitable techniques known to those skilled in the art to
form side seals 62. The outer bag 54 may be made from a
thermoplastic material such as, for example, a thermoplastic film
material having a thickness of about 2.7 mils and being available
from Curwood, Inc., a company having offices located in Oshkosh,
Wisconsin.
As representatively illustrated in Figs. 2 and 3, the container 52
may include a resealable closure 64 which extends longitudinally
along the top portion of the outer bag 54. The resealable closure 64
can be selectively opened and closed. A tear means 66 for allowing
initial access into the outer bag 54, may be located above the
resealable closure 64. The tear means 66 allows tearing parallel to
the length of the resealable closure 64. The resealable closure 64
may include complimentary, interlocking male and female rib and
groove type zipper elements 68 which extend longitudinally along the
top portion of the outer bag 54. The zipper elements 68 may be
joined to a pair of bases 72 which are joined to and also extend
longitudinally across the top portion of the outer bag 54. The
zipper elements 68 and bases 72 may be made from any suitable
material such as a low density polyethylene material. The zipper
elements 68 may be flanked on either side by a pair of ribs 70 which
extend along the zipper elements 68 to help the user align and engage
the male and female zipper elements 68. The ribs 70 may generally
have a triangular cross-section and may also be made from a low
density polyethylene material.
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214238
The tear means 66 for allowing initial access into the outer bag 54
as representatively illustrated in Figs. 2 and 3, is configured such
that the top portion of the outer bag 54 extending above the tear
means 66 can be torn and removed by the user. The tear means 66 may
include two pairs of tear beads 76 which are located on the front
panel 56 and back panel 58 of the outer bag 54. The tear beads 76
extend in a generally parallel, spaced relation to the male and
female zipper elements 68. The tear beads 76 provide an upper and
lower boundary to the region being torn such that the zipper
elements 68 are not adversely affected when the top portion of the
outer bag 54 is torn and removed. The tear beads 76 may also be made
from a low density polyethylene material.
At least one stack of moist wipes 10 of the different aspects of the
present invention, as representatively illustrated in Fig. 1, is
inserted through the bottom of the outer bag 54 and the bottom edge
regions of the front panel 56 and back panel 58 are joined together
to form the bottom gusset 60. Any suitable number of stacks of moist
wipes 10 may be inserted into the outer bag 54 to provide the desired
number of moist wipes in the package. After the outer bag 54 is
filled and sealed to form the package of moist wipes 50, the top
portion of the outer bag 54 may be folded over onto the stack of
moist wipes 10. The excess material at the side edge regions of the
top portion of the outer bag may then be folded over the top edges of
the stack of wipes and sealed to the outer bag 54 along the side
seals 62.
In the first use, the user can open the package of moist wipes 50, as
representatively illustrated in Figs. 2 and 3, by gripping the tear
beads 76 along a side edge of the outer bag 54 and proceeding to tear
the top portion of the outer bag 54 to allow access to the resealable
closure 64. The resealable closure 64 may be selectively opened to
expose the stack of moist wipes 10, as representatively illustrated
in Fig. 1. After opening the resealable closure 64 and withdrawing a
desired number of sheets 12, the user can close the resealable
closure 64 to minimize the escape of any liquid. As long as the user
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21~~~~~
maintains the resealable closure 64 in the closed position when not
using the sheets 12, the sheets 12 should retain the desired amount
of liquid., ,In a particular aspect, the user may open the resealable
closure 64 of the outer bag 54 and withdraw enough sheets 12 from the
stack of moist wipes 10 to refill a conventional package for moist
wipes wherein the original wipes have been used and discarded. For
example, the user may use the stack of moist wipes 10 from the
package of moist wipes 50 of the present invention to refill a
conventional package for moist wipes, such as a plastic container or
tub, one or more times. In a particular aspect of the invention, the
user may withdraw a stack of 80 moist wipes from a 160-count package
of moist wipes 50 to refill a conventional 80-count package of moist
wipes. In such a configuration, a moisture barrier 24 may be placed
between the eightieth and eighty-first sheet to conveniently separate
the 160-count stack into two eighty-count stacks. Such placement of
the moisture barrier 24 also serves to indicate the appropriate
number of wipes needed to refill a conventional package.
The different aspects of the invention can advantageously provide
a package and stack of moist wipes which, when compared to
conventional packages and stacks of wipes, have a reduced migration
of liquid between the top and bottom of the stack. Thus, the package
of moist wipes, stack of moist wipes and method of the present
invention provide wipes which are not oversaturated or dried out even
after standing for a long period of time or being repeatedly exposed
to ambient air. In particular, the stack of moist wipes of the
present invention can be used to refill a conventional plastic .
container one or more times after the original stack of wipes has
been used by the consumer. Such stack and package of moist wipes can
be used for baby wipes, hand wipes, face wipes, cosmetic wipes,
household wipes, industrial wipes and the like.
Examples
The following examples are presented to provide a more detailed
understanding of the invention. The particular materials and
parameters are exemplary and are not intended to limit the scope of
the invention.
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CA 02142385 2002-02-20
Example 1
A coform basesheet having about 65 weight percent cellulosic fibers
and 35 weight percent polypropylene microfibers based on the dry
weight of the basesheet is provided. Liquid is added to the coform
basesheet such that the basesheet has about 340 weight percent liquid
based on the dry weight of the basesheet. The liquid is the same as
that used in wet wipes which are commercially available under the
trade - marks Kleenex~ Huggies~ Baby Wipes. The liquid includes
water, emollients, surfactants, preservatives, pH buffers, chelating
agents, or combinations thereof. The basesheet is selectively
divided into a plurality of individual sheets. The individual sheets
have an unfolded width of 19.1 centimeters and an unfolded length of
19.0 centimeters. The individual sheets are z-folded and arranged in
stacks of 160 sheets thereby forming 160-count stacks of moist wipes.
Each z-folded sheet or wipe has a folded width of 9.2 centimeters and
a length of 19.0 centimeters.
A moisture barrier having a barrier width of 9.2 centimeters and a
barrier length of 20.3 centimeters is placed between the eightieth
and eighty-first sheets in one of the 160-count stacks of moist
wipes. The moisture barrier is made from a thermoplastic film
material designated #9184 and available from Curwood, Inc., a company
having offices located in Oshkosh, Wisconsin. The 160-count stack of
moist wipes is placed inside a plastic bag which is then hermetically
sealed. The package of moist wipes is allowed to stand for 21 days
at ambient temperature. After 21 days the amount of liquid in every
third sheet in the stack of moist wipes is measured and recorded.
The data is representatively illustrated in Fig. 4.
Example 2
A 160-count stack of moist wipes is prepared as outlined in
Example 1. A moisture barrier having a barrier width of 11.7
centimeters and a barrier length of 21.6 centimeters is placed
between the eightieth and eighty-first sheet in the 160-count stack
of moist wipes. The moisture barrier is made from a thermoplastic
film material designated #9184 and available from Curwood, Inc. The
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214238
160-count stack of moist wipes is placed inside a plastic bag which
is then hermetically sealed. The package of moist wipes is allowed
to stand for 21 days at ambient temperature. After 21 days the
amount of liquid in every third sheet in the stack of moist wipes is
measured and recorded. The data is representatively illustrated in
Fig. 5.
Example 3
A 160-count stack of moist wipes is prepared as outlined in
Example 1. Moisture barriers having a barrier width of 9.2
centimeters and a barrier length of 20.3 centimeters are located
every 16 sheets in the 160-count stack of moist wipes. The moisture
barriers are made from a thermoplastic film material designated #9184
and available from Curwood, Inc. The 160-count stack of moist wipes
is placed inside a plastic bag which is then hermetically sealed.
The package of moist wipes is allowed to stand for 21 days at ambient
temperature. After 21 days the amount of liquid in every third sheet
in the stack of moist wipes is measured and recorded. The data is
representatively illustrated in Fig. 6.
Exampl a 4
A 160-count stack of moist wipes is prepared as outlined in
Example 1. Moisture barriers having a barrier width of 9.2
centimeters and a barrier length of 20.3 centimeters are located
every 40 sheets in the 160-count stack of moist wipes. The moisture
barriers are made from a thermoplastic film material designated #9184
and available from Curwood, Inc. The 160-count stack of moist wipes
is placed inside a plastic bag which is then hermetically sealed.
The package of moist wipes is allowed to stand for 21 days at ambient
temperature. After 21 days the amount of liquid in every third sheet
in the stack of moist wipes is measured and recorded. The data is
representatively illustrated in Fig. 7.
Example 5
A 160-count stack of moist wipes is prepared as outlined in
Example 1. A moisture barrier having a barrier width of 6.7
centimeters and a barrier length of 16.5 centimeters is placed
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21~23~~
between the eightieth and eighty-first sheets in the 160-count stack
of moist wipes. The moisture barrier is made form a thermoplastic
film material designated #9184 and available from Curwood, Inc. The
160-count stack of moist wipes is placed inside a plastic bag which
is then hermetically sealed. The package of moist wipes is allowed
to stand for 21 days at ambient temperature. After 21 days the
amount of liquid in every third sheet in the stack of moist wipes is
measured and recorded. The data is representatively illustrated in
Fig. 8.
Comparative Example 1
A 160-count stack of moist wipes is prepared as outlined in Example 1
with no moisture barrier. The 160-count stack of moist wipes is
placed inside a plastic bag which is then hermetically sealed. The
package of moist wipes is allowed to stand for 21 days at ambient
temperature. After 21 days the amount of liquid in every third sheet
in the stack of moist wipes is measured and recorded. The data is
representatively illustrated in Figs. 4-8 as a control to illustrate
the effects of adding at least one moisture barrier to the stack.
While the invention has been described in detail with respect to the
specific aspects thereof, it will be appreciated that those skilled
in the art, upon attaining an understanding of the foregoing, may
readily conceive of alterations to, variations of, and equivalents to
these aspects. Accordingly, the scope of the present invention
should be assessed as that of the appended claims and any equivalents
thereto.
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