U.S. patent application number 10/233331 was filed with the patent office on 2004-03-04 for cross-machine-direction nested absorbent pads with minimal waste geometries.
This patent application is currently assigned to KIMBERLY-CLARK WORLDWIDE, INC.. Invention is credited to Dopke, Jennifer L., Flesburg, Leon R., Heyn, David W., Jacobs, Mark C., Venturino, Michael B..
Application Number | 20040040650 10/233331 |
Document ID | / |
Family ID | 31887680 |
Filed Date | 2004-03-04 |
United States Patent
Application |
20040040650 |
Kind Code |
A1 |
Venturino, Michael B. ; et
al. |
March 4, 2004 |
CROSS-MACHINE-DIRECTION NESTED ABSORBENT PADS WITH MINIMAL WASTE
GEOMETRIES
Abstract
A method is provided for making absorbent pads that may have a
longitudinally asymmetric shape. The pads may be used in various
consumer absorbent articles. The method includes delivering a
supply of an absorbent web material in a machine-direction and
cutting the absorbent web material in a cross-direction to form a
repeating nested pattern of generally identically shaped and
oppositely oriented absorbent pads, the pads being disposed
longitudinally in the cross-direction of the absorbent web. The
pads are longitudinally asymmetric and nested such that the crotch
portion of one pad is oriented towards the back portions of
immediately adjacent pads, and adjacent nested pads share defining
cut lines such that there is no wastage of absorbent web material
between the nested pads.
Inventors: |
Venturino, Michael B.;
(Appleton, WI) ; Flesburg, Leon R.; (Neenah,
WI) ; Jacobs, Mark C.; (Appleton, WI) ; Heyn,
David W.; (Neenah, WI) ; Dopke, Jennifer L.;
(East Troy, WI) |
Correspondence
Address: |
STEPHEN E. BONDURA, ESQ.
DORITY & MANNING, P.A.
P.O. BOX 1449
GREENVILLE
SC
29602-1449
US
|
Assignee: |
KIMBERLY-CLARK WORLDWIDE,
INC.
|
Family ID: |
31887680 |
Appl. No.: |
10/233331 |
Filed: |
August 30, 2002 |
Current U.S.
Class: |
156/252 ;
118/109; 118/264; 428/192; 428/219; 428/220; 428/98; 83/284;
83/803 |
Current CPC
Class: |
B26F 1/44 20130101; Y10T
428/24777 20150115; A61F 13/15707 20130101; A61F 13/15723 20130101;
B65H 2801/57 20130101; Y10T 83/6648 20150401; Y10T 156/1056
20150115; Y10T 156/1052 20150115; Y10T 83/465 20150401; B26D 3/10
20130101; Y10T 428/24 20150115; B65H 35/08 20130101; Y10T 83/7158
20150401 |
Class at
Publication: |
156/252 ;
428/098; 428/192; 428/219; 428/220; 118/109; 118/264; 083/284;
083/803 |
International
Class: |
B32B 031/00 |
Claims
What is claimed is:
1. A method for making absorbent pads having a longitudinally
asymmetric shape between a back portion and front portion thereof,
said method comprising: delivering a supply of an absorbent web
material in a machine-direction flow; cutting the absorbent web
material in a cross-direction to form a repeating nested pattern of
generally identically shaped and oppositely longitudinally oriented
absorbent pads, the pads disposed longitudinally in the
cross-direction of the absorbent web; and wherein the absorbent
pads are longitudinally asymmetric and nested such that the back
portion of one pad is oriented towards the front portions of
immediately adjacent pads and adjacent nested pads share defining
cut lines such that wastage of the absorbent web material between
the nested pads is minimized.
2. The method as in claim 1, wherein there is generally less than
about 20% wastage of absorbent material between the nested
pads.
3. The method as in claim 1, wherein there is generally zero
wastage of absorbent material between the nest pads.
4. The method as in claim 1, wherein the absorbent web material is
supplied as a strip from a roll of the web material, the strip
having a cross-direction width.
5. The method as in claim 1, wherein the absorbent web material is
supplied in the form of a strip having a cross-directional width,
the individual absorbent pads having a longitudinal length less
than that of the cross-directional width of the web material but a
nested pair of the absorbent pads having a combined nested
longitudinal length equal to the cross-directional width of the web
material.
6. The method as in claim 5, wherein the absorbent pads are
symmetrical about a longitudinal centerline axis therethrough.
7. The method as in claim 6, wherein the absorbent pads have a
generally T-shaped configuration with a front ear portion having a
width measured in the machine-direction of greater than about 1.5
times that of a center crotch portion.
8. The method as in claim 7, wherein an angle of divergence is
defined at a cut line between the crotch portion and the ear
portion, the cut line also defining an angle of divergence for an
adjacent pad from a forward-most point of its longitudinal
centerline axis to the crotch portion.
9. The method as in claim 7, wherein cut line between the crotch
portion and the ear portion is generally straight.
10. The method as in claim 8, wherein the cut line between the
crotch portion and the ear portion is curved.
11. The method as in claim 8, wherein the ear portions have a
height defined by a cut line from the longitudinal centerline
forward-most point of the adjacent pads to a side of the strip of
web material, the ear height cut line being shared by the next
commonly oriented pad in the repeating pattern.
12. The method as in claim 6, wherein the absorbent pads have a
generally T-shaped configuration with a front ear portion and a
crotch portion extending longitudinally at a first width therefrom
and diverging to a back portion having a width greater than the
width of the crotch portion.
13. The method as in claim 12, wherein the absorbent pads are
symmetrical about a longitudinal centerline axis therethrough.
14. The method as in claim 12, wherein a machine-direction
centerline axis of the strip of web material passes through a
centerpoint of the diverging line between the crotch portion and
front portion.
15. The method as in claim 14, wherein the diverging line is
generally straight.
16. The method as in claim 14, wherein the diverging line is
generally sinusoidal.
17. The method as in claim 12, wherein the crotch portion and back
portion have generally parallel sides along their respective width
sections.
18. The method as in claim 12, wherein sides of the crotch portion
are generally straight and parallel to sides of the back portion of
the same pad.
19. The method as in claim 12, wherein sides of the crotch portion
are generally curved and the mirror image of sides of the back
portion of the same pad.
20. The method as in claim 4, wherein the absorbent pads have a
longitudinal length equal to the cross-directional width of the
strip of web material.
21. The method as in claim 20, wherein a single cross-directional
cut line defines a common side of adjacent nested pads.
22. The method as in claim 20, wherein the absorbent pads are
symmetrical about a longitudinal centerline axis thereof.
23. The method as in claim 20, wherein the pads have a front ear
portion and a crotch portion extending longitudinally therefrom,
wherein an angle of divergence is defined at a cut line between the
crotch portion and the ear portion that corresponds to the same
angle for the immediately adjacent pad.
24. The method as in claim 23, wherein the cut line between the
crotch portion and ear portion is generally straight.
25. The method as in claim 23, wherein the cut line between the
crotch portion and ear portion is generally sinusoidal.
26. The method as in claim 23, wherein a machine-direction
centerline axis of the strip of web material passes through a
center point of the line of divergence between the crotch portions
and ear portions of the pads.
27. The method as in claim 20, wherein the crotch and back portions
of a pad have parallel cross-directional sides that also define
parallel sides of the ear portions for adjacent nested pads.
28. The method as in claim 20, wherein the crotch and back portion
of a pad have common sides that are generally parallel to the sides
of the ear portions of the same pad.
29. The method as in claim 20, wherein the crotch and back portions
of a pad have common curved sides that are generally the mirror
image of sides of the ear portions of the same pad.
30. The method as in claim 20, wherein the ear portions have a
width measured in the machine-direction that is greater than about
1.5 times that of the crotch portion.
31. A method for making absorbent pads having a longitudinally
asymmetric shape between a back portion and front portion thereof,
said method comprising: delivering a supply of an absorbent web
material having generally parallel sides in a machine-direction
flow; cutting the absorbent web material in a cross-direction
dimension of the web material to define a repeating pattern of
nested pairs of absorbent pads disposed longitudinally in the
cross-direction; the cross-direction cuts being made such that a
back portion of one pad is oriented towards the front portion of
the immediately adjacent pads and each pad shares common cut lines
with immediately adjacent pads; and wherein the pads are defined
with a front portion that is wider in the machine-direction than
the crotch portion and the pads are symmetrical along a
longitudinal center axis thereof.
32. The method as in claim 31, wherein the crotch portion of one
pad is nested completely between the front portions of immediately
adjacent pads.
33. The method as in claim 31, wherein the crotch portion of one
pad is nested completely between the back portions of immediately
adjacent pads.
34. The method as in claim 33, wherein the pads have a longitudinal
length equal to a cross-direction width of the web material.
35. The method as in claim 34, wherein adjacent pads share a common
cut line disposed at an angle between perpendicular and parallel to
the machine-direction sides of the web material such that a
longitudinal centerline axis of the web material passes through a
center point of the cut line.
36. The method as in claim 35, wherein the angled cut line is
straight.
37. The method as in claim 35, wherein the angled cut line is
sinusoidal.
38. The method as in claim 31, wherein the front portion of the
pads include ears defining a greatest width dimension of the pads,
and wherein the ears of alternate pads in the repeating pattern
share common cut lines.
39. The method as in claim 38, wherein the crotch portion of the
pads is nested between the back portions of the immediately
adjacent pads.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
forming shaped absorbent pad structures from an absorbent web, the
pads being suitable for use in disposable absorbent articles such
as diapers, child's training pants, feminine care articles,
incontinence articles, swim pants, and the like.
BACKGROUND
[0002] Many types of disposable consumer products such as diapers,
training pants, feminine care articles, incontinence articles, and
the like, utilize an absorbent pad structure for absorbing and
wicking away bodily fluids. The absorbent pads are conventionally
formed from an absorbent web, typically a nonwoven fibrous web
material formed by known techniques. For example, the absorbent web
may be formed by employing conventional air forming techniques
wherein fibers and typically a superabsorbent material are mixed
and entrained in an air stream and then directed onto a forming
surface to form the web. The absorbent web may then be directed for
further processing and assembly with other components to produce a
final absorbent product.
[0003] With another conventional technique, preformed absorbent web
sheets or layers are delivered into a manufacturing line from a
preformed supply, such as a supply roll. The sheets or layers have
been separated into adjacent strips having various configurations
of repeat pattern "nested" shapes wherein the shape of one strip is
substantially nested with the shape of at least one immediately
adjacent strip.
[0004] Absorbent web material formed on a remote base machine and
supplied to the manufacturing line from a roll or other supply form
generally has a significant cost disadvantage as compared to air
laid webs formed on a converting machine. With the air laid web,
the trim waste can be immediately recycled by returning the waste
to the upstream fiberizing equipment. On the other hand, with the
roll material, the geographical separation of the base machine
makes recycling of the trim waste impractical and often cost
prohibitive. In this regard, the nesting feature mentioned above
has been desirable to reduce the amount of waste that is generated
from the supply (roll) of absorbent web It has been recognized that
particular nested strip shapes can be more readily adapted to
high-speed manufacturing processes. The more easily processed
strip-shapes have a repeat pattern that is substantially
symmetrical with respect to their longitudinal dimension, the
shapes being arranged longitudinally in the machine-direction of
the web. With such longitudinally-symmetric nested patterns, a
single cycle of the repeat pattern provides an individual web
segment wherein the shape of a first lengthwise half portion of the
segment substantially matches the shape of the longitudinally
opposed other half portion. However, such longitudinally symmetric
pads have been shown, in certain application, to be less desirable
from an end product fit, comfort, and performance aspects.
[0005] As a result, it has been desirable to construct absorbent
pads from web segments that are longitudinally-asymmetric. With
such a construction, the resulting pads may provide improved
product fit, comfort, and performance. However, the dividing of an
absorbent web into strips having a nested pattern shape of
longitudinally asymmetric segments generates a significant amount
of trim waste, particularly along the machine-direction sides of
the absorbent web.
[0006] Examples of suggestions in the art to reduce trim waste may
be found, for example, in U.S. Pat. Nos. 5,587,437; 5,695,846;
5,580,411; 4,862,574; EP 0 539 032; and EP 0 670 153.
[0007] The present invention provides a method for producing
longitudinally asymmetric nested pad structures in a continuous
absorbent web wherein there is virtually zero waste of the web
material.
SUMMARY OF THE INVENTION
[0008] Objects and advantages of the invention will be set forth in
part in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0009] The present invention provides an improved method for making
absorbent pads having a longitudinally asymmetric shape. Such pads
may be used in various applications of disposable consumer
absorbent articles, such as diapers, child's training pants,
feminine care articles, incontinence articles, swim pants, and the
like. The pads are longitudinally asymmetric in that the back
portion has a different shape or configuration as compared to the
crotch or front portion of the pad. As mentioned, longitudinally
asymmetric pads of this type have proven to be superior with
respect to product fit, comfort, and performance as compared to
longitudinally symmetric pads. The present method provides a
technique for mass producing such pads from a continuous strip of
absorbent web material in a manner so that there is virtually zero
waste of the web material.
[0010] In accordance with one embodiment of the present method, the
absorbent web material is delivered in the form of a continuous
strip or series of adjacent strips, for example from a supply roll,
in a machine-direction flow. In other words, the parallel sides of
the strip of material lie in the machine-direction. The absorbent
web material is cut in a cross-direction to form a repeating nested
pattern of cross-directional and generally identically shaped pads.
The pads are nested in that any two adjacent pads forming a nested
pair are oriented in longitudinally opposite directions in the
cross-direction of the absorbent web. In other words, the
longitudinal centerline of the pads lies generally perpendicular to
the machine-direction of the web material.
[0011] The pads are defined by cross-directional cuts such that the
crotch portion of one pad is oriented towards the back portions of
immediately adjacent pads. Adjacent nested pads share common
defining cut lines such that there is no wastage of absorbent
material between the nested pads. Each pad is longitudinally
asymmetric with respect to the crotch and back portions. For
example, in one particular embodiment, the back portion of the pads
includes ears that define the widest width of the pad, with a
smaller width crotch section extending longitudinally from the ears
and back portion.
[0012] In one particular embodiment, the individual absorbent pads
are defined across the strip of absorbent web material such that
each pad has a longitudinal length that is less than the
cross-directional width of the web material. In this embodiment,
however, a nested pair of the absorbent pads has a combined nested
longitudinal length that is equal to the cross-directional width of
the web material. For example, according to this particular
embodiment, the absorbent pads may be generally T-shaped with a
back ear portion having a width measured in the machine-direction
that is about twice that of the center crotch portion. The pads are
symmetrical about a longitudinal centerline axis therethrough. In
other words, the pads can be symmetrically folded lengthwise. In
this particular embodiment, the back ear portion may have a height
defined by a cross-directional cut line that is shared by the next
commonly oriented pad in the repeating pattern. Thus, all of the
pads having the crotch portions oriented in one direction would
have adjacent ears defined by a common cross-directional cut line.
The oppositely oriented or nested pads have crotch portions nested
against the ears of their respective adjacent pads. With this
particular arrangement, the cut line defining the ears of adjacent
commonly oriented pads corresponds to the longitudinal centerline
of the pad nested therebetween.
[0013] In another embodiment of a generally T-shaped absorbent pad,
the crotch portion has a first longitudinally extending section
having a first width, this section diverging along lines into a
longitudinally extending second section having a second greater
width. With this embodiment, the pads are still symmetrical about
their longitudinal centerline axis. The diverging lines between the
first width section and the second width section have a center
point through which the machine-direction centerline axis of the
strip of web material passes. This line may be straight or
sinusoidal. The sides of the crotch section along the first width
and second greater width sections may be generally parallel.
[0014] In still further embodiments, the absorbent pads are defined
with cross-directional cuts such that each pad has a longitudinal
length equal to the cross-directional width of the strip of
absorbent web material. In this embodiment, a single
cross-directional cut line defines a common longitudinal side of
adjacent nested pads. These pads may have a back ear portion with a
center crotch portion extending longitudinally therefrom. An angle
of divergence is defined at a cut line between the crotch portion
and the ear portion that corresponds to the same angle for the
immediately adjacent and oppositely oriented pad. This cut line may
be generally straight or sinusoidal, and has a center point through
which the machine-direction centerline axis of the strip of web
material passes.
[0015] The method will be explained in greater detail below by
reference to particular embodiments thereof.
BRIEF DESCRIPTION OF THE FIGURES
[0016] FIG. 1 shows a perspective view of a strip of absorbent web
material being cut into a repeating pattern of nested
cross-directionally disposed absorbent pads.
[0017] FIG. 2 shows a representative top view of an alternate
embodiment of an alternating pattern nested configuration according
to the present method.
[0018] FIG. 3 is a representative top view of the repeating nested
pattern configuration illustrated in FIG. 1.
[0019] FIG. 4 shows a representative top view of still another
embodiment of a repeating nested configuration according to the
invention.
[0020] FIG. 5 is a schematic perspective view of an in-line
processing method that may incorporate features of the present
invention.
DETAILED DESCRIPTION
[0021] The invention will now be described in detail with reference
to particular embodiments thereof. The embodiments are provided by
way of explanation of the invention, and are not meant as a
limitation of the invention. For example, features described or
illustrated as part of one embodiment may be used with another
embodiment to yield still a further embodiment. It is intended that
the present invention include these and other modifications and
variations as come within the scope and spirit of the
invention.
[0022] The present method is particularly suited for the
manufacture of pad structures from a web of absorbent material, the
pads intended for use in various disposable consumer absorbent
products. Such products include, but are not limited to, diapers,
child's training pants, feminine care articles, incontinence
articles, swim pants, and the like. The invention is not limited to
any particular type or composition of absorbent web material, and
may be practiced with any suitable absorbent web material known to
those skilled in the art. The absorbent web material may include
any structure and combination of components which are generally
compressible, conformable, non-irritating to a wearer's skin, and
capable of absorbing and retaining liquids and certain body
wastes.
[0023] For example, the absorbent web material may include
cellulosic fibers (e.g., wood pulp fibers), other natural fibers,
synthetic fibers, woven or nonwoven sheets, scrim netting or other
stabilizing structures, superabsorbent material, binder materials,
surfactants, selected hydrophobic materials, pigments, lotions,
odor control agents or the like, as well as combinations thereof.
In a particular embodiment, the absorbent web material is a matrix
of cellulosic fluff and superabsorbent hydrogel-forming particles.
The cellulosic fluff may comprise a blend of wood pulp fluff. One
suitable type of fluff is identified with the trade designation CR
1654, available from U.S. Alliance Corp. of Coosa Pines, Ala., and
is a bleached, highly absorbent sulfact wood pulp containing
primarily soft wood fibers. As a general rule, the superabsorbent
material is present in the absorbent web in an amount of from about
5 to about 90 weight percent based on total weight of the web. The
web may have a density, for example, within the range of about 0.10
to about 0.35 grams per cubic centimeter.
[0024] Superabsorbent materials are well known in the art and can
be selected from natural, synthetic, and modified natural polymers
and materials. The superabsorbent materials can be inorganic
materials, such as silica gels, or organic compounds, such as
crosslinked polymers. Typically, a suberabsorbent material is
capable of absorbing at least about 15 times its weight in liquid,
and desirably is capable of absorbing more than about 25 times its
weight in liquid. Suitable superabsorbent materials are readily
available from various suppliers. For example, Favor SXM 880
superabsorbent is available from Stockhausen, Inc., of Greensboro,
N.C., USA; and Drytech 2035 is available from Dow Chemical Company,
of Midland Mich., USA.
[0025] Subsequent to or after being cut from the nested pattern as
described herein, the individual absorbent pads may be partially or
wholly wrapped or encompassed by a suitable tissue wrap that aids
in maintaining the integrity and shape of the pad.
[0026] The absorbent materials may be formed into a web structure
by employing various conventional methods and techniques. For
example, the absorbent web may be formed with a dry-forming
technique, an airlaying technique, a wet-forming technique, a
foam-forming technique, or the like, as well as combinations
thereof. Methods and apparatus for carrying out such techniques are
well known in the art.
[0027] The absorbent web material may also be a coform material.
The term "coform material" generally refers to composite materials
comprising a mixture or stabilized matrix of thermoplastic fibers
and a second non-thermoplastic material. As an example, coform
materials may be made by a process in which at least one meltblown
die head is arranged near a chute through which other materials are
added to the web while it is forming. Such other materials may
include, but are not limited to, fibrous organic materials such as
woody or non-woody pulp such as cotton, rayon, recycled paper, pulp
fluff and also superabsorbent particles, inorganic absorbent
materials, treated polymeric staple fibers and the like. Any of a
variety of synthetic polymers may be utilized as the melt-spun
component of the coform material. For instance, in some
embodiments, thermoplastic polymers can be utilized. Some examples
of suitable thermoplastics that can be utilized include
polyolefins, such as polyethylene, polypropylene, polybutylene and
the like; polyamides; and polyesters. In one embodiment, the
thermoplastic polymer is polypropylene. Some examples of such
coform materials are disclosed in U.S. Pat. Nos. 4,100,324 to
Anderson, et al.; U.S. Pat. No. 5,284,703 to Everhart, et al.; and
U.S. Pat. No. 5,350,624 to Georger, et al.; which are incorporated
herein in their entirety by reference thereto for all purposes.
[0028] In a particular aspect of the invention, the absorbent web
material can be provided with an absorbent capacity of at least
about 8 g/g employing 0.9 wt % saline (8 grams of 0.9 wt % saline
per gram of absorbent web). The absorbent capacity of the absorbent
web can alternatively be at least about 9 g/g, and can optionally
be at least about 10 g/g to provide improved benefits.
Additionally, the absorbent capacity may be up to about 50 g/g, or
more, to provide desired performance.
[0029] In another aspect, the web of absorbent material can be
provided with a tensile strength value of at least about 1 N/cm
(Newtons per cm of "width" of the material, where the "width"
direction is perpendicular to the applied force). The tensile
strength of the absorbent web can alternatively be at least about
1.5 N/cm, and can optionally be at least about 2 N/cm to provide
improved benefits. In another aspect, the web of absorbent material
can be provided with a tensile strength value of up to a maximum of
about 100 N/cm, or more. The tensile strength of the absorbent web
can alternatively be up to about 10 N/cm, and can optionally be up
to about 20 N/cm to provide improved benefits.
[0030] The selected tensile strength should provide adequate
processibility of the web throughout the manufacturing process, and
can help to produce articles that exhibit desired combinations of
softness and flexibility.
[0031] The absorbent material web is also selected so that the
individual absorbent pad structures possess a particular individual
total absorbency depending on the intended article of use. For
example, for infant care products (e.g., diapers), the total
absorbency can be within the range of about 300-900 grams of 0.9 wt
% saline, and can typically be about 500 g of saline. For adult
care products, the total absorbency can be within the range of
about 1000-1600 grams of saline, and can typically be about 1300 g
of saline. For feminine care products, the total absorbency can be
within the range of about 7-50 grams of saline, and can typically
be within the range of about 30-40 g of saline.
[0032] Aspects of the present method include delivering a supply of
the absorbent web material in a machine-direction flow. The web
material is delivered in the form of a continuous ribbon or strip
from a supply source, such as a roll. Optionally, the web strip may
be supplied directly from an in-line manufacturing operation. The
"machine-direction" is the direction along which the strip travels
length-wise through a particular processing stage. The web material
strip has a "cross-direction" or "width" that is perpendicular to
the machine-direction. The material also has a depth-wise "z"
direction that is perpendicular to the cross-direction and
machine-direction.
[0033] Referring to FIG. 1, an absorbent web material 16 is
supplied in the form of a ribbon or strip 24. As mentioned, the web
material 16 may be supplied from a roll or directly from an in-line
manufacturing operation. The strip of web material 24 is conveyed
in a machine-direction 18 and has machine-direction sides 20
defined by opposite parallel sides of the strip 24. The strip of
web material 24 also has a cross-direction dimension 22 that may be
considered as the "width" of the strip 24. FIG. 1 illustrates a
single strip of web material 24, however, it should be appreciated
that an absorbent web material may be supplied in the form of a
plurality of adjacent strips 24. After the absorbent pads 10 have
been defined in the strips according to the present invention, the
plurality of strips could be separated for subsequent delivery to
an absorbent article manufacturing line.
[0034] Still referring to FIG. 1, the strip 24 of absorbent web
material is cut in the cross-direction 22 to form a repeating
nested pattern of cross-directional absorbent pads 10. The pads 10
are oriented so that a longitudinal centerline axis 32 thereof lies
in the cross-direction 22 of the strip 24. The pads are nested in
that any two adjacent pads form a nested pair and are oriented in
longitudinally opposite directions in the cross-direction 22 of the
absorbent pad. For example, referring to FIG. 1, absorbent pad X is
nested with absorbent pad Y such that a crotch section 12 of pad Y
is oriented towards a front portion 14 of pad X.
[0035] As described in greater detail below with respect to the
remaining figures, the absorbent pads 10 may desirably have a
longitudinally asymmetric shape wherein the crotch portion 12 and
front portion 14 have different widths. The pads are, however, in
particular embodiments symmetrical with respect to the longitudinal
axis 32 defined therethrough. In other words, the pad may be folded
along the axis 32 into symmetric halves. In alternate embodiments,
the pads 10 may be non-symmetrical with respect to the axis 32.
[0036] Referring to FIG. 1, the process of cutting the strip 24 of
web material with cross-direction cuts in order to define the
individual absorbent pads 10 is illustrated as carried out by a
conventional and schematically illustrated rotary knife or roll 26
having blades 28 defined thereon in a pattern corresponding to the
nested shape of the pads 10. It should be appreciated that any
suitable cutter mechanism may be utilized in this regard, including
future developed methods and devices. Conventional cutter
mechanisms and devices are well known in the art, and can include
rotary knives, die cutters, water-cutters, laser cutters, and the
like, as well as combinations thereof. The method according to the
present invention is not limited by any particular cutting method
or apparatus.
[0037] Referring again to FIG. 1, it can be seen that the adjacent
nested pads 10 share common defining cut lines such that there is a
minimum of wastage of absorbent material between the nested pads
10. In the embodiment of FIG. 1, there is minimum or no wastage of
material. With conventional nested patterns, there is typically
between about 30% to about 35% wastage of material between adjacent
pads. The present invention encompasses nested configurations
wherein the wastage is minimal, desirably less than about 20%, and
more desirably at zero wastage. The ability to mass produce
longitudinally asymmetric pads without wastage of the web material
is a significant feature. The pads have a crotch section generally
designated as 12, a "back" section 15, and a longitudinally
opposite "front" portion generally designated as 14. The crotch
section 12 and back section 15 may be considered as a common
section, particularly if they have the same shape and dimensions as
in FIGS. 2 and 3. The front portion 14 is configured for the waist
band portion of an absorbent article and includes "ears" 30 that
define the widest width dimension of the pad 10. Accordingly, each
pad 10 may have a minimum crotch width 36 and a maximum waist band
or front section width 34. The ratio of the front section width to
the crotch width can be at least about 1.5 to 1. Alternatively, the
front section to crotch width ratio may be at least about 2 to 1,
and can optionally be about 3 to 1. Additionally, the waist band to
crotch width ratio can be up to about 10 to 1 to provide desired
levels of fit and performance.
[0038] It should also be appreciated that the crotch width 36 can
be tailored for particular desired absorbent articles. For example,
in an absorbent pad 10 designated for a feminine care article, the
crotch width 36 may be within the range of about 2 to 5
centimeters. In a particular feminine care configuration, the
crotch width can be about 3.8 centimeters (about 1.5 inches). For
an absorbent pad designated for an infant care article, the crotch
width can be within the range of about 4 to 12 centimeters. In a
particular infant care configuration, the crotch width can be about
10 centimeters (about 4 inches). For an absorbent pad designated
for an adult care article, the crotch width can be within a range
of about 7 to 20 centimeters. In a particular adult care
configuration, the crotch width can be about 15 centimeters (about
6 inches).
[0039] It should be appreciated that a vast number of shapes and
configurations are possible for defining the cross-directional
nested pads 10 in accordance with the invention, particularly for
longitudinally asymmetric pads as described herein. The pads 10
will generally have an identical shape and will be symmetrical with
respect to the longitudinal axis 32 therethrough. The longitudinal
orientation of the pads will alternate, and alternate pads will
share common defining cuts or chords so that there is virtually no
wastage of absorbent material between adjacent pads. Particular
embodiments of pad configurations within the scope of the invention
are illustrated in FIGS. 2 through 4. It should be appreciated,
however, that such embodiments are for illustrative purposes only,
and that the invention is not limited to any particular
configuration.
[0040] Referring to FIG. 2, a nested configuration of
cross-directionally oriented pads 10 is illustrated. In this
particular embodiment, the pads 10 have a generally T-shaped
configuration with the front section 14 including ears 30. A
relatively constant width crotch section 12 extends longitudinally
from the front section 14. A longitudinal centerline axis 32 may be
defined through the pad 10. The crotch section 12 has a relatively
constant width designated by the arrow 36. The front portion 14
with ears 30 defines the widest width dimension 34 of the pad 10.
In this particular embodiment, the pad has an overall length that
is less than the cross-directional width of the web strip 24.
However, a nested pair of the absorbent pads, for example pads X
and Y in FIG. 2, have an overall combined longitudinal length that
is equal to the cross-directional width of the web strip 24. For
example, particularly with generally T-shaped pads, the front
portion 14 with ears 30 may have a width 34 measured in the
machine-direction that is about twice that of the width 36 of the
center crotch portion 12. The pads are symmetrical about the
longitudinal center line axis 32. The ears may have a "height" in
the cross-direction defined by cross-directional cut lines I and H.
These cross-directional cut lines H and I are shared by the next
commonly oriented pad in the repeating pattern. For example, pads X
and Z in FIG. 2 are commonly oriented in the repeating pattern and
share the cross-directional cut line H. The oppositely oriented or
nested pad (pad Y in FIG. 2) is nested against the ears 30 of the
respective adjacent pads X and Z. With this particular arrangement,
the cut line H defining the ears 30 of adjacent commonly oriented
pads X and Z also corresponds to the longitudinal center line 32 of
the nested pad Y. This relationship can be particularly seen in
FIG. 2.
[0041] Still referring to FIG. 2, it can be seen that any
individual pad 10 is defined by a series of cut lines. The
rearward-most longitudinal point of the back section 15 is defined
by diverging cut lines D and E. Lines D and E meet at the
longitudinal center line axis 32 of the pad 10 at a point where a
separate cut line A defines ear portions 30 of adjacent and
oppositely oriented pads. The crotch section 12 is defined by
opposite and parallel cut lines B and C. These lines may be
arcuate. The crotch section 12 diverges into the front portion 14
by way of diverging cut lines F and G. An angle of divergence J is
defined between the crotch portion and ears of the back portion for
any given pad. Because of the nested configuration, this angle J
also corresponds to an angle of divergence for an adjacent pad from
a forwardmost point of the longitudinal center line axis of a
respective pad to its crotch defining line C or B, as particularly
seen in FIG. 2. The defining lines F and G between the crotch
portion 12 and front portion 14 may be either straight or
curved.
[0042] An alternate embodiment of a generally T-shaped nested pad
configuration is illustrated in FIG. 4. In this particular
embodiment, the crotch portion 12 has a first generally constant
width (width 36a) section defined by cut lines B' and C'. The back
section 15 has a relatively constant width (width 36b) section
defined by cut lines B and C. Line B' may be parallel to line B,
and line C' may be parallel to line C. In an alternate embodiment,
lines B and B' may be curved mirror images of each other. Likewise,
lines C and C' may be curved mirror images of each other. The
crotch width 36a is less than that of the back section 36b.
Diverging lines D' and E' are defined between the crotch section 12
and back section 15. A machine-direction longitudinal centerline 33
of the web strip 24 passes through the midpoints L and K of the
defining lines D' and E', respectively. The cut lines D' and E' may
be generally straight, as illustrated in the Figure, or may be
sinusoidal wherein a zero-node of the sinusoidal line corresponds
to the midpoints L and K. The contoured crotch section 12 and back
section 15 according to this embodiment may be particularly desired
for certain absorbent article applications. By having the center
point of the transitional cut lines D' and E' lie along the
longitudinal center line axis 33 of the web strip 24, it is ensured
that the alternating nested pads 10 have the identical
configuration.
[0043] It should be appreciated that various contoured profiles of
the crotch section12 may be defined so long as the contours are
symmetric with respect to the longitudinal center line axis 32 of
the individual pads and, for the oppositely oriented nested pads,
are equally distanced from the machine-direction longitudinal
center line 33 of the web strip 24.
[0044] An alternate embodiment of a cross-directional nested pad
configuration 10 is illustrated in FIG. 3. With this embodiment,
each individual pad 10 has an overall longitudinal length that is
equal to the cross-directional width of the web strip 24. The
crotch portion 12 and back portion 15 share common lines. Thus, the
crotch portion 12 and back portion 15 of one pad is nested
completely between front portions 14 of the immediately adjacent
pads. The front portion of a respective pad has a width 34 that is
greater than the width 36 of the pad's crotch portion 12 and back
portion 15. For example, the width 34 may be twice that of the
width 36. The crotch portion 12 and back portion 15 are defined by
generally parallel cut lines B and C, and the front portion 14 is
defined by the generally parallel cut lines H and I. Lines I and C
may be parallel as shown, or may be the curved mirror images of
each other. Likewise, lines H and B may be parallel as shown or may
be the curved mirror images of each other. Diverging cut lines F
and G are defined between the crotch portion 12 and front portion
14. These cut lines F and G may be generally straight, as
illustrated in the figure, or may be sinusoidal. The
machine-direction longitudinal center line axis 33 of the web 24
passes through the midpoints L and K of the respective cut lines F
and G. An angle of divergence J is defined between, for example,
cut line B and F, and is equal to the angle of divergence between
cut lines F and H. Each pad 10 is symmetric with respect to its
longitudinal center line axis 32. With the nested configuration as
illustrated in FIG. 3 wherein each individual pad 10 has an overall
longitudinal length equal to the cross-directional width of the web
strip 24, it can be seen that a single continuous cross-directional
cut (lines H, F, and B) is shared by immediately adjacent and
oppositely oriented pads such that there is no wastage of the web
material between adjacent pads.
[0045] Once the web strips 24 have been cut into a
cross-directional nested pad configuration according to the
invention, the strips may be conveyed directly to an in-line
manufacturing process wherein the individual pads 10 are
incorporated into a disposable consumer absorbent article, such as
diapers, child's training pants, feminine care articles,
incontinence articles, swim pants, and the like. Many conventional
manufacturing lines for such articles are cross-directional process
lines and, thus, the cross-directional orientation of the pads 10
may be easily accommodated into such a processing line. In the
event that the absorbent article chassis is not symmetrical, it
would be necessary to rotate or flip alternate pads so that all of
the pads are oriented longitudinally in the same direction. If the
absorbent article chassis is symmetrical, the pads 10 can be
accommodated at either orientation. Any manner of automated
conventional rotating and positioning modules or units may be used
in this regard. Such devices are well known to those skilled in the
art.
[0046] Alternatively, the web strips 24 having the individual pads
10 defined therein may be formed into a roll or stacked
configuration for later incorporation into an in-line manufacturing
process. If this is the case, it may be desired not to completely
cut each of the individual pads from the web strip. For example, a
relatively small percentage of the lines defining the pads may be
left uncut so that the web strip 24 maintains its integrity. This
would aid in the later feeding of the web strip and individual pads
10 into a manufacturing line. This feature may be accomplished, for
example, merely by "interrupting" the blades 28 on the rotary
cutter 26 illustrated in FIG. 1. Alternatively, the cut lines may
comprise perforated lines wherein the pads are separated into
spaced apart individual pads at some later point in the
manufacturing process. If the strip 24 maintains its integrity, the
strip may be stored, for example, in the form of a roll, or a
stacked festooned configuration.
[0047] As mentioned, the web strip 24 with individual pads 10
defined therein may be incorporated directly into an in-line
absorbent article manufacturing process line. A conceptual
schematic representation of this process is provided in FIG. 5. It
should be appreciated, however, that FIG. 5 is in no way meant to
limit the in-line manufacturing process or machinery utilized in
such a process, and is provided merely as conceptually illustrating
an example of the invention.
[0048] Referring to FIG. 5, the strip of absorbent web material 24
is illustrated as being conveyed through a rotary knife cutter 26
so as to define oppositely oriented and cross-directionally nested
pads 10, as discussed in detail above. The web strip 24, and other
material components of an absorbent article, may be appropriately
guided through the manufacturing process with one or more operative
guiding mechanisms 48. Various conventional web guide mechanisms 48
can be employed to keep the various webs and materials
substantially aligned with respect to a machine-direction center
line of the manufacturing process. For example, an absorbent web or
a material supplied on a roll can tend to take on a camber if the
web is level-wound or processed in any way that bends the web in
the cross-machine-direction. Web guides can effectively counteract
the effects of this camber. While any operative web guide may be
employed, those that minimize the cross-directional bending of the
web materials are desired. For example, the web bending can be
reduced by minimizing any wrapping of the various webs around an
idler roll. Suitable web guides can, for example, include a camber
roller FIFE guide, which is available from the FIFE Corporation of
Oklahoma City, Okla.
[0049] Although not illustrated in FIG. 5, the absorbent web strip
24 may be delivered to a phasing accumulator device, the operation
of which is well known in the art. Such an accumulator device can
change the running path length of the web strip 24 to selectively
advance or retard eventual positioning of the web strip 24 and pads
10 with respect to downstream processing equipment.
[0050] Additionally, the manufacturing process may also include
compressing of the absorbent web material to reduce its thickness.
The compressing may also increase the density of the base web
material, and may increase the longitudinal length and/or the
cross-directional width of the web. The compressing may be
substantially uniformly or non-uniformly applied across the surface
of the absorbent web material. The compressing may be configured to
emboss a desired pattern of embossments along the machine-direction
and/or cross-direction. Referring to FIG. 5, the compressing action
can be provided by a counter rotating pair of nip rollers 46.
Alternative compressing devices or systems can include converging
gap rollers, converging gap conveyor belts or the like, as well as
combinations thereof.
[0051] An optional first tissue layer 40 may be assembled to the
base web strip 24. In one configuration, a bonding device such as
provided by an adhesive applicator, may be appropriately disposed
to secure the first tissue layer 40 to the underside of the
absorbent material strip 24 having the pads 10 defined therein. In
the conceptual embodiment of FIG. 5, the web strip 24 with
cross-directional nested pads 10 defined therein and first tissue
layer 40 are conveyed to a module 44 that rotates the pads 10 to a
common longitudinal machine-direction and also spaces the pads 10
apart on the first tissue layer 40 at a desired spacing. Various
such modules 44 for rotating and placing items in an in-line
manufacturing process are known to those skilled in the art and
used in absorbent article manufacturing lines. Certain types of
these modules may also perform cutting operations prior to rotating
and placing the absorbent pads 10. As an example of such modules
44, reference is made to U.S. Pat. Nos. 6,319,347 B1; 6,139,004;
5,556,504; 5,224,405; 5,104,116; and 4,608,115, the disclosures of
which are incorporated herein by reference for all purposes.
[0052] At least one supplemental layer of absorbent material may be
incorporated with the individual pads 10. In the embodiment
illustrated in FIG. 5, this supplemental layer can be provided by
pledgets 58. The pledget 58 may be substantially equal to the full
length of its associated corresponding absorbent pad 10, or may be
shorter than the pad 10. Likewise, the width of each pledget 58 may
be equal to, greater than, or less than the smallest width
dimension of the corresponding absorbent pad 10. The pledgets 58
may be defined from a suitable pledget web 54 delivered from an
operative pledget supply 52 and suitably transported by an
operative conveyor. A pledget cutter device 56 may be used to
separate the pledget web 51 into a plurality of the individual
pledgets 58 to be selectively placed onto the individual absorbent
pads 10. The individual pledgets 58 can be positioned at locations
that are spaced apart along the machine-direction of the first
tissue layer 40 and spaced pads 10. A securing mechanism, such as
provided by an adhesive applicator 50 may be used to operatively
attach the individual pledgets 58 to the moving tissue 40 and pads
10.
[0053] The resulting structure may then be subjected to further
conventional downstream processing operations. For example, the
assembled components may be processed by a system of assembly nip
rollers 65, which can enhance the desired attachments between the
assembled components. The resulting structure can then be separated
into individual absorbent assemblies 100 by employing a suitable
cutter mechanism, such as is represented by the cutter device 62.
The assemblies 100 may be further combined with other components,
as desired, for example, the absorbent assemblies 100 may be
laminated to a layer of liner material 68 provided from a suitable
liner supply 70. Additionally, the absorbent assemblies 100 may be
combined with a layer of outer cover material 64 provided from a
suitable cover supply 66. The composition of such inner and outer
liner and cover materials is well known to those skilled in the
art, and the invention is not limited to any particular type of
material.
[0054] It should be understood that the invention encompasses
various other embodiments, modifications, and equivalents to the
embodiments of the invention described herein which, after reading
the description of the invention herein, may suggest themselves to
those skilled in the art without departing from the scope and
spirit of the present invention.
* * * * *