U.S. patent application number 16/035783 was filed with the patent office on 2018-11-08 for bonding apparatus and method.
The applicant listed for this patent is The Procter & Gamble Company. Invention is credited to Hailing Bao, Joseph Allen Eckstein, Theresa Lynn Galie.
Application Number | 20180318143 16/035783 |
Document ID | / |
Family ID | 51210744 |
Filed Date | 2018-11-08 |
United States Patent
Application |
20180318143 |
Kind Code |
A1 |
Galie; Theresa Lynn ; et
al. |
November 8, 2018 |
Bonding Apparatus and Method
Abstract
The present disclosure relates to methods and apparatuses for
mechanically bonding substrates together. The apparatuses may
include a pattern roll having three or more pattern elements
protruding radially outward, wherein each pattern element includes
a pattern surface. The pattern surfaces are also separated from
each other by gaps having minimum widths. The pattern roll may be
adjacent an anvil roll to define a nip between the pattern surfaces
and the anvil roll, wherein the pattern roll is biased toward the
anvil roll to define a nip pressure between pattern surfaces and
the anvil roll. As substrates advance between the pattern roll and
anvil roll, the substrates are compressed between the anvil roll
and the pattern surfaces to form a discrete bond region between the
substrates. During the bonding process, some of yielded substrate
material also flows from under the pattern surfaces and into the
gaps to form gap grommet regions.
Inventors: |
Galie; Theresa Lynn;
(Cincinnati, OH) ; Eckstein; Joseph Allen;
(Sunman, IN) ; Bao; Hailing; (Blue Ash,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Procter & Gamble Company |
Cincinnati |
OH |
US |
|
|
Family ID: |
51210744 |
Appl. No.: |
16/035783 |
Filed: |
July 16, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14301416 |
Jun 11, 2014 |
10052237 |
|
|
16035783 |
|
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|
61836745 |
Jun 19, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 13/15577 20130101;
B29C 65/18 20130101; B29C 65/56 20130101; B29C 66/71 20130101; B29C
66/729 20130101; B29C 66/81429 20130101; B29C 65/609 20130101; A61F
13/15699 20130101; A61F 13/15739 20130101; B29C 66/71 20130101;
A61F 13/15585 20130101; B29C 66/43 20130101; B29C 66/83411
20130101; B29C 66/431 20130101; B29C 66/21 20130101; B29C 66/72327
20130101; A61F 2013/15991 20130101; B29C 65/8223 20130101; B29C
66/1122 20130101; B29C 66/83415 20130101; B29L 2031/4878 20130101;
B29C 66/83511 20130101; B29K 2023/06 20130101; B29C 66/929
20130101; B29C 66/727 20130101; B29C 66/71 20130101; B29C 66/232
20130101; B29C 65/522 20130101; B29C 66/72343 20130101; B29C
65/7894 20130101; B29C 65/7841 20130101; B29C 66/02241 20130101;
B29C 66/7294 20130101; A61F 13/15731 20130101; Y10T 428/2481
20150115; B29C 66/71 20130101; B29C 65/02 20130101; B29K 2023/12
20130101; B29K 2067/003 20130101 |
International
Class: |
A61F 13/15 20060101
A61F013/15; B29C 65/00 20060101 B29C065/00; B29C 65/02 20060101
B29C065/02; B29C 65/56 20060101 B29C065/56; B29C 65/60 20060101
B29C065/60; B29C 65/78 20060101 B29C065/78; B29C 65/82 20060101
B29C065/82 |
Claims
1. A method of bonding substrates, the method comprising the steps
of: rotating an anvil roll; rotating a pattern roll adjacent the
anvil roll, the pattern roll including a base circumferential
surface, a first pattern element including a first pattern surface,
a second pattern element including a second pattern surface, and a
third pattern element including a third pattern surface; wherein
each pattern surface defines an area, A, wherein A is greater than
about 0.25 mm.sup.2 and less than about 2.00 mm.sup.2; wherein each
pattern element protrudes outward from the base circumferential
surface to define a distance, Hp, between the first, second, and
third pattern surfaces and the base surface, and wherein each
pattern element is bounded by a perimeter; wherein the first and
second pattern surfaces are separated by a first gap having a
minimum width, D1, wherein the first and third pattern surfaces are
separated by a second gap having a minimum width, D2, and wherein
the second and third pattern surfaces are separated by a third gap
having a minimum width, D3, and wherein D1, D2, and D3 are greater
than 0.20 mm and less than about 3.00 mm; biasing the bonding roll
toward the anvil roll to define a nip pressure of greater than
about 40,000 PSI and less than about 60,000 PSI between each
pattern surface and the anvil roll; advancing a first substrate and
a second substrate in a machine direction between the pattern roll
and the anvil roll; and compressing the first substrate and the
second substrate between the anvil roll and the first, second, and
third pattern surfaces to form a discrete bond region between the
first and second substrates.
2. The method of claim 1, wherein the step of compressing further
comprises moving a first portion of material of the first and
second substrates from between the first pattern surface and the
anvil to the first gap and the second gap.
3. The method of claim 2, wherein the step of compressing further
comprises moving a second portion of material of the first and
second substrates from between the second pattern surface and the
anvil to the first gap and the third gap.
4. The method of claim 3, wherein the step of compressing further
comprises moving a third portion of material of the first and
second substrates from between the third pattern surface and the
anvil to the second gap and the third gap.
5. The method of claim 1, wherein each pattern surface defines
substantially the same area, A.
6. The method of claim 5, wherein the area, A, is about 0.70
mm.sup.2.
7. The method of claim 1, wherein at least one of D1, D2, and D3 is
about 0.30 mm.
8. The method of claim 1, wherein D1, D2, and D3 are substantially
the same.
Description
FIELD OF THE INVENTION
[0001] The present disclosure relates to methods for manufacturing
absorbent articles, and more particularly, to apparatuses and
methods for bonding substrates that may be used as components of
absorbent articles.
BACKGROUND OF THE INVENTION
[0002] Along an assembly line, various types of articles, such as
for example, diapers and other absorbent articles, may be assembled
by adding components to and/or otherwise modifying an advancing,
continuous web of material. For example, in some processes,
advancing webs of material are combined with other advancing webs
of material. In other examples, individual components created from
advancing webs of material are combined with advancing webs of
material, which in turn, are then combined with other advancing
webs of material. In some cases, individual components created from
advancing web or webs are combined with other individual components
created from other advancing web or webs. Webs of material and
component parts used to manufacture diapers may include:
backsheets, topsheets, leg cuffs, waist bands, absorbent core
components, front and/or back ears, fastening components, and
various types of elastic webs and components such as leg elastics,
barrier leg cuff elastics, stretch side panels, and waist elastics.
Once the desired component parts are assembled, the advancing
web(s) and component parts are subjected to a final knife cut to
separate the web(s) into discrete diapers or other absorbent
articles.
[0003] During the assembly process, various components and/or
advancing webs of material may be bonded together in various ways.
For example, in some processes, advancing webs and/or components
may be bonded together with adhesives. In other processes,
advancing webs and/or components may be mechanically bonded
together with heat and pressure without the use of adhesives. An
example of such a mechanical bonding method and apparatus is
disclosed in U.S. Pat. No. 4,854,984, wherein two laminae are
bonded together by advancing through a nip between a patterned
cylinder and an anvil cylinder. Pattern elements on the patterned
cylinder exert pressure on the two laminae against the anvil roll
to create discrete bond sites. More particularly, bond sites are
created as the extreme nip pressure compresses and yields the
laminae material in areas between the pattern elements and the
anvil. During the bonding process, some of the yielded material may
flow from the bond site to areas surrounding the perimeter of the
pattern element.
[0004] However, extreme nip pressures may exceed the compressive
yield strength of cold work powder metal tool steels. In addition,
current mechanical bonding methods are susceptible to pattern
element chipping, spalling, buckling, and/or otherwise fracturing,
referred to generally as bond tool breakdown, sometimes
necessitating frequent and costly repairs. These mechanical bonding
methods may also damage the laminae by forming holes and/or tears
in or around the bond sites. For example, pattern elements may
become deformed and/or fail after prolonged use due to high
stresses that occur in the center portions of the pattern element
during the bonding operation. In some instances, such high stresses
may cause craters to form in the bonding surfaces of pattern
elements. As a pattern element degrades, the bonds created thereby
may have inconsistent aesthetic appearances; have relatively weaker
strengths; and may tear or cut the bonded laminae in areas adjacent
to the bonds. In addition, as the web basis weight of laminae
decreases, bonds may become more susceptible to bond defects such
as tearing and pinholes at relatively high nip pressures.
[0005] Consequently, it would be beneficial to provide a method and
apparatus for mechanically bonding substrates that produces bond
sites with relatively low damage to the laminae and with reduced
bond tool breakdown.
SUMMARY OF THE INVENTION
[0006] The present disclosure relates to methods and apparatuses
for mechanically bonding substrates together. The apparatuses may
include a pattern roll having three or more pattern elements
protruding radially outward, wherein each pattern element includes
a pattern surface. The pattern surfaces are also separated from
each other by gaps having minimum widths. The pattern roll may be
adjacent an anvil roll to define a nip between the pattern surfaces
and the anvil roll, wherein the pattern roll is biased toward the
anvil roll to define a nip pressure between pattern surfaces and
the anvil roll. As substrates advance between the pattern roll and
anvil roll, the substrates are compressed between the anvil roll
and the pattern surfaces to form a discrete bond region between the
substrates. During the bonding process, some of yielded substrate
material also flows from under the pattern surfaces and into the
gaps to form gap grommet regions.
[0007] In one embodiment, an apparatus for dynamically bonding
substrates comprises: an anvil roll; a bonding roll including: base
circumferential surface; a first pattern element including a first
pattern surface having a first pattern area, A1, wherein A1 is
greater than about 0.25 mm.sup.2 and less than about 2.00 mm.sup.2,
wherein the first pattern element protrudes outward from the base
circumferential surface to define a distance, Hp1, between the
first pattern surface and the base circumferential surface, and
wherein the first pattern element is bounded by a first perimeter;
a second pattern element including a second pattern surface having
a second pattern area, A2, wherein A2 is greater than about 0.25
mm.sup.2 and less than about 2.00 mm.sup.2, wherein the second
pattern element protrudes outward from the base circumferential
surface to define a distance, Hp2, between the second pattern
surface and the base circumferential surface, and wherein the
second pattern element is bounded by a second perimeter; and a
third pattern element including a third pattern surface having a
third pattern area, A3, wherein A3 is greater than about 0.25
mm.sup.2 and less than about 2.00 mm.sup.2, wherein the third
pattern element protrudes outward from the base circumferential
surface to define a distance, Hp3, between the third pattern
surface and the base circumferential surface, and wherein the third
pattern element is bounded by a third perimeter; wherein the first
and second pattern surfaces are separated by a first gap having a
minimum width, D1, wherein the first and third pattern surfaces are
separated by a second gap having a minimum width, D2, and wherein
the second and third pattern surfaces are separated by a third gap
having a minimum width, D3, and wherein D1, D2, and D3 are greater
than 0.20 mm and less than about 3.00 mm; and wherein the bonding
roll is adjacent the anvil roll to define a nip between the first,
second, and third pattern surfaces and the anvil roll; and wherein
the bonding roll is biased toward the anvil roll to define a nip
pressure of greater than about 40,000 PSI and less than about
60,000 PSI between each pattern surface and the anvil roll.
[0008] In another embodiment, a method of bonding substrates
comprises the steps of: rotating an anvil roll; rotating a pattern
roll adjacent the anvil roll, the pattern roll including a base
circumferential surface, a first pattern element including a first
pattern surface, a second pattern element including a second
pattern surface, and a third pattern element including a third
pattern surface; wherein each pattern surface defines an area, A,
wherein A is greater than about 0.25 mm.sup.2 and less than about
2.00 mm.sup.2; wherein each pattern element protrudes outward from
the base circumferential surface to define a distance, Hp, between
the first, second, and third pattern surfaces and the base surface,
and wherein each pattern element is bounded by a perimeter; wherein
the first and second pattern surfaces are separated by a first gap
having a minimum width, D1, wherein the first and third pattern
surfaces are separated by a second gap having a minimum width, D2,
and wherein the second and third pattern surfaces are separated by
a third gap having a minimum width, D3, and wherein D1, D2, and D3
are greater than 0.20 mm and less than about 3.00 mm; biasing the
bonding roll toward the anvil roll to define a nip pressure of
greater than about 40,000 PSI and less than about 60,000 PSI
between each pattern surface and the anvil roll; advancing a first
substrate and a second substrate in a machine direction between the
pattern roll and the anvil roll; and compressing the first
substrate and the second substrate between the anvil roll and the
first, second, and third pattern surfaces to form a discrete bond
region between the first and second substrates.
[0009] In yet another embodiment, a laminate comprises: a first
substrate comprising nonwoven fibers; a second substrate comprising
nonwoven fibers; a discrete bond between the first substrate and
the second substrate, the discrete bond comprising: a first
membrane region comprising nonwoven fibers of the first and second
substrates that have been yielded under pressure and are fused
together, defining a first area, A1, greater than about 0.25
mm.sup.2 and less than about 2.00 mm.sup.2; a second membrane
region comprising nonwoven fibers of the first and second
substrates that have been yielded under pressure and are fused
together, defining a second area, A2, greater than about 0.25
mm.sup.2 and less than about 2.00 mm.sup.2; a third membrane region
comprising nonwoven fibers of the first and second substrates that
have been yielded under pressure and are fused together, defining a
third area, A3, greater than about 0.25 mm.sup.2 and less than
about 2.00 mm.sup.2; a first gap grommet region separating the
first membrane region and the second membrane region, wherein the
first gap grommet region comprises material of the first and second
substrates that has been transferred from the first membrane region
and second membrane region, and wherein the first gap grommet
region defines a minimum width, D1, that is greater than 0.20 mm
and less than about 3.00 mm; a second gap grommet region separating
the first membrane region and the third membrane region, wherein
the second gap grommet region comprises material of the first and
second substrates that has been transferred from the first membrane
region and third membrane region, wherein the second gap grommet
region defines a minimum width, D2, that is greater than 0.20 mm
and less than about 3.00 mm; a third gap grommet region separating
the second membrane region and third membrane region, wherein the
third gap grommet region comprises material of the first and second
substrates that has been transferred from the second membrane
region and the third membrane region, wherein the third gap grommet
region defines a minimum width, D3, that is greater than 0.20 mm
and less than about 3.00 mm; an outer grommet region partially
surrounding the first membrane region, wherein the outer grommet
region comprises material of the first and second substrates that
has been transferred from the first membrane region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic side view of a bonding apparatus.
[0011] FIG. 2 is a detailed view of the bonding apparatus of FIG.
1.
[0012] FIG. 3 is a perspective view a pattern roll.
[0013] FIG. 4 is a detailed isometric view of three pattern
elements.
[0014] FIG. 5 is a top side view of the pattern elements of FIG.
4.
[0015] FIG. 6 is a cross-sectional view of a pattern element of
FIG. 5 taken along line 6-6.
[0016] FIG. 7 is a cross-sectional view of a pattern element of
FIG. 5 taken along line 7-7.
[0017] FIG. 8 is a detailed side view along the cross direction CD
of the first and second pattern elements of FIG. 5 bonding a first
substrate with a second substrate.
[0018] FIG. 9 is a detailed side view along the cross direction CD
of the first and third pattern elements of FIG. 5 bonding a first
substrate with a second substrate.
[0019] FIG. 10 is a detailed side view along the machine direction
MD of the second and third pattern elements of FIG. 5 bonding a
first substrate with a second substrate.
[0020] FIG. 11 is a top side view of a perspective view of a
discrete bond region.
[0021] FIG. 12 is a cross-sectional view of the bond region of FIG.
11 taken along line 12-12.
[0022] FIG. 13 is a cross-sectional view of the bond region of FIG.
11 taken along line 13-13.
[0023] FIG. 14 is a cross-sectional view of the bond region of FIG.
11 taken along line 14-14.
[0024] FIG. 15 is a perspective view of a diaper pant.
[0025] FIG. 16A is a partially cut away plan view of the diaper
pant shown in FIG. 15.
[0026] FIG. 16B is a partially cut away plan view of a second
embodiment of a diaper pant.
[0027] FIG. 17A is a cross-sectional view of the diaper pants of
FIGS. 16A and 16B taken along line 17A-17A.
[0028] FIG. 17B is a cross-sectional view of the diaper pants of
FIGS. 16A and 16B taken along line 17B-17B.
[0029] FIG. 18 is a schematic side view of a converting apparatus
adapted to manufacture pre-fastened, pant diapers.
[0030] FIG. 19A is a view of a continuous length of chassis
assemblies from FIG. 18 taken along line A-A.
[0031] FIG. 19B1 is a view of a discrete chassis from FIG. 18 taken
along line B1-B1.
[0032] FIG. 19B2 is a view of a discrete chassis from FIG. 18 taken
along line B2-B2.
[0033] FIG. 19C is a view of continuous lengths of advancing front
and back side panel material from FIG. 18 taken along line C-C.
[0034] FIG. 19D is a view of multiple discrete chassis spaced from
each other along the machine direction MD and connected with each
other by the front and back side panel material from FIG. 18 taken
along line D-D.
[0035] FIGS. 19E is a view of folded multiple discrete chassis with
the front and back side panel material in a facing relationship
from FIGS. 18 taken along line E-E.
[0036] FIGS. 19F is a view of two discrete absorbent articles
advancing the machine direction MD from FIGS. 18 taken along line
F-F.
[0037] FIG. 20 is a graphical representation illustrating strengths
of discrete bonds created by relatively small pattern element
groupings and relatively large pattern element groupings over a
range of pattern surface pressures.
[0038] FIG. 21A illustrates the pattern element orientation of the
Inventive Nubs on a pattern roll in the machine direction MD and
cross direction CD.
[0039] FIG. 21B illustrates the pattern element orientation of the
Control Nubs on a pattern roll in the machine direction MD and
cross direction CD.
[0040] FIG. 22 illustrates an example test sample for use with the
peel strength test method.
DETAILED DESCRIPTION OF THE INVENTION
[0041] The following term explanations may be useful in
understanding the present disclosure: "Absorbent article" is used
herein to refer to consumer products whose primary function is to
absorb and retain soils and wastes. "Diaper" is used herein to
refer to an absorbent article generally worn by infants and
incontinent persons about the lower torso. The term "disposable" is
used herein to describe absorbent articles which generally are not
intended to be laundered or otherwise restored or reused as an
absorbent article (e.g., they are intended to be discarded after a
single use and may also be configured to be recycled, composted or
otherwise disposed of in an environmentally compatible manner).
[0042] An "elastic," "elastomer" or "elastomeric" refers to
materials exhibiting elastic properties, which include any material
that upon application of a force to its relaxed, initial length can
stretch or elongate to an elongated length more than 10% greater
than its initial length and will substantially recover back to
about its initial length upon release of the applied force.
[0043] As used herein, the term "joined" encompasses configurations
whereby an element is directly secured to another element by
affixing the element directly to the other element, and
configurations whereby an element is indirectly secured to another
element by affixing the element to intermediate member(s) which in
turn are affixed to the other element.
[0044] "Longitudinal" means a direction running substantially
perpendicular from a waist edge to a longitudinally opposing waist
edge of an absorbent article when the article is in a flat out,
uncontracted state, or from a waist edge to the bottom of the
crotch, i.e. the fold line, in a bi-folded article. Directions
within 45 degrees of the longitudinal direction are considered to
be "longitudinal." "Lateral" refers to a direction running from a
longitudinally extending side edge to a laterally opposing
longitudinally extending side edge of an article and generally at a
right angle to the longitudinal direction. Directions within 45
degrees of the lateral direction are considered to be
"lateral."
[0045] The term "substrate" is used herein to describe a material
which is primarily two-dimensional (i.e. in an XY plane) and whose
thickness (in a Z direction) is relatively small (i.e. 1/10 or
less) in comparison to its length (in an X direction) and width (in
a Y direction).
[0046] Non-limiting examples of substrates include a web, layer or
layers or fibrous materials, nonwovens, films and foils such as
polymeric films or metallic foils. These materials may be used
alone or may comprise two or more layers laminated together. As
such, a web is a substrate.
[0047] The term "nonwoven" refers herein to a material made from
continuous (long) filaments (fibers) and/or discontinuous (short)
filaments (fibers) by processes such as spunbonding, meltblowing,
carding, and the like. Nonwovens do not have a woven or knitted
filament pattern.
[0048] The term "machine direction" (MD) is used herein to refer to
the direction of material flow through a process. In addition,
relative placement and movement of material can be described as
flowing in the machine direction through a process from upstream in
the process to downstream in the process.
[0049] The term "cross direction" (CD) is used herein to refer to a
direction that is generally perpendicular to the machine
direction.
[0050] The term "yield" is used herein to refer to permanent and
non-reversible material displacement due to subjecting the material
to mechanical stress past the yield stress of the material and/or
permanent and non-reversible material displacement due to
subjecting the material to temperatures higher than the melting
point of the material.
[0051] The term "pant" (also referred to as "training pant",
"pre-closed diaper", "diaper pant", "pant diaper", and "pull-on
diaper") refers herein to disposable absorbent articles having a
continuous perimeter waist opening and continuous perimeter leg
openings designed for infant or adult wearers. A pant can be
configured with a continuous or closed waist opening and at least
one continuous, closed, leg opening prior to the article being
applied to the wearer.
[0052] The present disclosure relates to methods and apparatuses
for manufacturing absorbent articles, and in particular, to methods
and apparatuses for mechanically bonding substrates together. The
apparatuses may include a pattern roll and an anvil roll. The
pattern roll may include three or more pattern elements protruding
radially outward, wherein each pattern element includes a pattern
surface. And the pattern roll may be adjacent the anvil roll to
define a nip between the pattern surfaces and the anvil roll,
wherein the pattern roll is biased toward the anvil roll to define
a nip pressure between pattern surfaces and the anvil roll. As the
first and second substrates advance between the pattern roll and
anvil roll, the first substrate and the second substrate are
compressed between the anvil roll and the pattern surfaces to form
a discrete bond region between the first and second substrates.
More particularly, during the bonding process, heat generated by
the nip pressure causes the first and second substrate material to
yield. And the yielded material is pressed together to form a bond
region. In addition, some of the yielded material flows outward
from under the pattern surfaces to form one or more outer grommet
regions along the outer perimeter of one or more pattern elements.
As discussed in more detail below, the pattern surfaces are also
separated from each other by gaps having minimum widths. As such,
during the bonding process, some of the yielded material also flows
from under the pattern surfaces and into the gaps to form gap
grommet regions.
[0053] It is to be appreciated that various arrangements and
configurations of the apparatuses and methods herein may be used to
bond various types of substrates together. For example, as
discussed in more detail below, apparatuses and methods according
to the present disclosure may be utilized to bond various
substrates together during the production of various components of
absorbent articles, such as diapers.
[0054] FIG. 1 shows an embodiment of a bonding apparatus 100 that
may be used to bond a first substrate 102 and a second substrate
104 together to form a laminate 105. As shown in FIG. 1, the
bonding apparatus 100 may include a bonding roll 106, also referred
to herein as a pattern roll 106, adapted to rotate around an axis
of rotation 108, and an anvil roll 110 adapted to rotate around an
axis of rotation 112. The anvil roll 110 includes an outer
circumferential surface 114. And as shown in FIGS. 1-4, the pattern
roll 106 may include one or more groupings 115 of pattern elements
116, each pattern element 116 including a pattern surface 118. With
particular reference to FIG. 4, the pattern roll 106 may include a
base circumferential surface 120, wherein each pattern element 116
includes a circumferential wall 122 that protrudes radially outward
from the base circumferential surface 120 to define a distance, Hp,
between the pattern surface 118 and the base surface 120. The
circumferential wall 122 also defines an outer perimeter 124 of the
pattern element 116. It is to be appreciated that in some
embodiments, the circumferential wall 122 may be perpendicular to
base circumferential surface 120 or may sloped or tapered with
respect to the base circumferential surface 120. As shown in FIGS.
1 and 2, the pattern roll 106 is adjacent the anvil roll 110 so as
to define a nip 126 between the pattern roll 106 and the anvil roll
110, and more particularly, to define a nip 126 between the pattern
surface 118 of each pattern element 116 and the anvil roll 110. As
discussed in more detail below, the pattern roll 106 may be biased
toward the anvil roll 110 to define a nip pressure between the
pattern surface 118 and the anvil roll 106. It is to be appreciated
that the anvil roll 110 may also be biased toward the pattern roll
106, and/or the pattern and anvil rolls may be biased toward each
other to define the nip pressure between the pattern surface 118
and the anvil roll 110. It is to be appreciated that the pattern
roll 106 and the anvil roll 110 may be configured to rotate such
that the pattern surfaces 118 on the pattern roll 106 and the outer
circumferential surface 114 of the anvil roll 110 move at the same
speeds or different speeds. It is to be appreciated that the
bonding methods and apparatuses herein can be configured to bond
substrates together that are advancing at various speeds, such as
for example, speeds of about 240 feet or more per minute.
[0055] As shown in FIGS. 1 and 2, during the bonding operation, the
pattern roll 106 may rotate in a first direction 128 around the
axis of rotation 108 of the pattern roll 106, and the anvil roll
110 may rotate in a second direction 130, opposite the first
direction 128, around the axis of rotation 112 of the anvil roll
110. The first substrate 102 and second substrate 104 may advance
in a machine direction MD between the pattern roll 106 and the
anvil roll 110. More particularly, the first substrate 102 includes
a first surface 132 and a second surface 134 opposite the first
surface 132, and the second substrate 104 includes a first surface
136 and a second surface 138 opposite the first surface 136. As
such, the first surface 132 of the first substrate 102 is contacted
by the pattern roll 106, and the second surface 138 of the second
substrate 104 is contacted by the anvil roll 110. And the second
surface 134 of the first substrate 102 and the first surface 136 of
the second substrate 104 contact each other. As first substrate 102
and second substrate 104 advance through the nip 126 between the
pattern surface 118 of a pattern element 116 and the anvil roll
110, the pattern element 116 contacts the first substrate 102 and
compresses the first substrate 102 and second substrate 104 between
the pattern surface 118 of the pattern element 116 and the anvil
roll 110. In turn, heat generated by the nip pressure causes the
first and second substrate material to yield. And, as described
below with reference to FIGS. 8-10, the pattern surface 118 presses
yielded material 140 of the first and second substrates 102, 104
together to form a discrete bond region 142 between the first and
second substrates 102, 104. Thus, the apparatus 100 may form a
laminate 105 including first and second substrates 102, 104 bonded
together by discrete bond regions 142, without the use of
adhesives. It is to be appreciated, however, that the bonding
apparatus 100 may also be used in combination with adhesives.
Although FIG. 1 shows the apparatus 100 bonding two substrates
together, it is to be appreciated that the apparatus may bond more
than two substrates together. In addition, it is to be appreciated
that the apparatus may also be used to bond fibers of nonwoven
together on a single substrate and/or emboss a pattern on a single
substrate. It should also be appreciated that the pattern elements
116 may be configured with the same or different distances, Hp,
between the pattern surface 118 and the base surface 120. In
addition, the distance, Hp, may be greater than the sum of the
thicknesses of the substrates 102, 104 being bonded.
[0056] It is to be appreciated that various pattern element
configurations may be used with the bonding apparatuses and
processes herein. Various quantities pattern elements may be
arranged in groupings to form discrete bonds. For example, FIGS.
3-7 show a grouping 115 of pattern elements 116 with pattern
surfaces 118 separated by gaps 144. The gaps 144 between the
pattern elements provide a location, in addition to regions outside
of and adjacent to the perimeter 124 of the pattern element 116,
for yielded substrate material 140 to flow during the bonding
process. Allowing yielded substrate material 140 to flow to the
gaps 144 during the bonding process may help provide stress relief
on the pattern element 116, which may in turn, help reduce the
frequency of pattern element deformations, including buckling,
and/or failures and may help provide for more relatively more
consistent and stronger bonds.
[0057] With continued reference back to FIGS. 4-7, the grouping 115
of pattern elements 116 may include a first pattern element 116a
including a first pattern surface 118a; a second pattern element
116b including a second pattern surface 118b; and a third pattern
element 116c including a third pattern surface 118c. The first
pattern element 116a protrudes radially outward from the base
circumferential surface 120 to define a distance, Hp1, between the
first pattern surface 118a and the base surface 120. The second
pattern element 116b protrudes radially outward from the base
circumferential surface 120 to define a distance, Hp1, between the
second pattern surface 118b and the base surface 120. The third
pattern element 116c protrudes radially outward from the base
circumferential surface 120 to define a distance, Hp3, between the
third pattern surface 118c and the base surface 120. It is to be
appreciated that the distances Hp1, Hp2, and/or Hp3 may be the same
or different. Embodiments that are configured with distances Hp1,
Hp2, and/or Hp3 are different may utilize bearer ring
configurations such as described in European Patent Publication No.
EP1635750B1.
[0058] Although the grouping 115 of pattern elements 116 is
depicted as including three pattern elements, it is to be
appreciated that groupings may include more than three pattern
elements. As shown in FIG. 4, the first pattern surface 118a and
the second pattern surface 118b are separated by a first gap 144a;
the first pattern surface 118a and the third pattern surface 118c
are separated by a second gap 144b; and the second pattern surface
118b and the third pattern surface 118c are separated by a third
gap 144c. The first gap 144a may define a minimum width, D1; the
second gap 144b may define a minimum width, D2; and the third gap
144c may define a minimum width, D3. As such, the first pattern
surface 118a may be separated from the second and third pattern
surfaces 118b, 118c by minimum distances of D1 and D2,
respectively. And the second and third pattern surfaces may be
separated from each other by the minimum distance, D3. The pattern
elements may be arranged to also include gaps of various sizes. In
some instances, the minimum widths (D1, D2, D3) of the gaps 144 may
be greater than 0.20 mm and less than about 3.00 mm. In some
embodiments, the minimum widths D1, D2, and/or D3 of the gaps 144
may be about 0.30 mm. It is to be appreciated that in some pattern
element groupings, the gap widths D1, D2, and/or D3 may be the same
or different.
[0059] It is to be appreciated that the apparatus 100 may also be
configured with various different configurations of pattern
elements 116. For example, the first pattern surface 118a may
define a first area, A1; the second pattern surface 118b may define
a second pattern area, A2; and the third pattern surface may define
a third pattern area, A3. As such, the pattern elements may be
configured to also include pattern areas A of various sizes. In
some instances, the pattern areas (A1, A2, A3) may be greater than
about 0.25 mm.sup.2 and less than about 2.00 mm.sup.2,. In some
embodiments, pattern areas A1, A2, and/or A3 may be about 0.70
mm.sup.2. It is to be appreciated that in some pattern element
groupings, the pattern areas A1, A2, and/or A3 may be the same or
different. In other examples, the pattern roll may be configured
with pattern elements having different sizes and shapes. For
example, in some embodiments, the pattern elements may have a
perimeter that defines circular, square, rectangular, and various
types of other shapes. For example, the pattern elements may have a
perimeter that defines an elliptical shape, such as shown in FIG.
5. As such, in some embodiments, an elliptically shaped pattern
element may have a major axis of about 1.27 mm and minor axis of
about 0.56 mm. In some instances, the pattern elements may be
configured such that resulting bond regions also offer aesthetic
benefits such as, for example, a stitched like appearance along
with a relatively smooth texture feel to the skin.
[0060] As discussed above, during the bonding process, the first
and second substrates 102, 104 advance in the machine direction MD
between the rotating pattern roll 106 and the anvil roll 110. As
the pattern roll 106 and the anvil rotate 110, the pattern surfaces
118 of the pattern elements 116 contact the first substrate 106 and
compress the first and second substrates 102, 104 in the nip 126
between the pattern surface 118 and the outer circumferential
surface 114 of the anvil roll 112. Nip pressure between the pattern
surface 118 of the pattern element 116 and the anvil roll 110
exerted on the first and second substrates 102, 104 causes some
material 140 of the first and second substrates 102, 104 to yield.
As shown in FIGS. 8-10, some of the yielded material 140 between
the pattern surfaces 118a, 118b, 118c and the anvil roll 110 is
fused together in first locations 158 between the pattern surfaces
118a, 118b, 118c and the anvil roll 110. In addition, some of the
yielded material 140 flows out from between the pattern surfaces
118a, 118b, 118c and the anvil roll 110 to second locations 160
along the perimeter 124 of the pattern element 116. And some of the
yielded material 140 flows out from between the pattern surfaces
118a, 118b, 118c and the anvil roll 110 to third locations 162
along the gaps 144a, 144b, 144c. As discussed in more detail below,
the yielded material 140 in the first locations 158, second
locations 160, and third locations 162 fuses together to form a
discrete bond 142 between the first substrate 102 and the second
substrate 104. More particularly, the yielded material 140 in the
first locations 158 fuses together to form membrane regions 164 of
the bond 142; the yielded material 140 in the first locations 160
fuses together to form outer grommet regions 166 of the bond 142;
and the yielded material 140 in the third locations 162 fuses
together to form gap grommet regions 168 of the bond 142.
[0061] FIGS. 11-14 show an example bond 142 between the first and
second substrates 102, 104 that may be created by the apparatus
100. As shown in FIG. 11, the bond 142 includes first regions 164,
also referred to as membrane regions 164, that correspond with the
first locations 158 wherein some of the yielded material 140
between the pattern surfaces 118 and the anvil roll 110 is fused
together between the pattern surfaces 118 and the anvil roll 110.
In particular, the bond 142 may include three membrane regions
164a, 164b, 164c that correspond with the pattern surfaces 118a,
118b, 118c, respectively. The bond 142 also includes second regions
166, also referred to as outer grommet regions 166, that correspond
with the second locations 160 where some of the yielded material
140 that flowed out from between the pattern surfaces 118 and the
anvil roll 110 to areas along the perimeter 124 of the pattern
element 116 is fused together. In addition, the bond 142 includes
third regions 168, also referred to as gap grommet regions 168,
that correspond with the third locations 162 where some of the
yielded material 140 that flowed out from between the pattern
surfaces 118 and the anvil roll 110 to areas along the gaps 144 of
the pattern element 116 is fused together. In some embodiments, the
bond 142 may include three gap grommet regions 168a, 168b, 168c
that correspond with the first, second, and third gaps 144a, 144b,
144c, respectively. As such, the outer region 166 may define a
perimeter of the discrete bond 142, the perimeter surrounding a
central region of the discrete bond 142 wherein the membrane
regions 164 and the gap grommet regions 168 are located inside the
central region.
[0062] As previously mentioned, the gaps 144 separating the pattern
element provide locations, in addition to regions outside of and
adjacent to the perimeters 124 of the pattern elements 116, for
yielded substrate material 140 to flow and form gap and outer
grommet regions during the bonding process. In contrast, when
bonding substrates with pattern elements having relatively large
pattern areas, yielded substrate material may be required to flow
relatively longer distances to form perimeter grommet regions
outside of and adjacent the perimeter of the pattern element.
Stated another way, when bonding substrates with pattern elements
having relatively small pattern areas, yielded substrate material
may be required to flow relatively shorter distances to form gap
grommet and outer grommet regions. The relatively shorter flow
distances of yielded material may also help reduce hydraulic-like
reactionary pressures in the nip. Further, some air may be
entrained in substrates during formation, and collapse of the air
bubbles, known as cavitation, may be significantly reduced by
shortening the flow distance path needed for grommet formation.
[0063] It is also to be appreciated that the grouping 115 of
pattern elements 116, such as shown in FIGS. 4-7, may create
discrete bonds 142 having substantially the same bond strengths as
discrete bonds created by pattern elements of a larger size and
separated by large gaps with reduced nip pressures. For example,
FIG. 20 provides a graph illustrating strengths of discrete bonds
created by relatively small pattern element grouping and relatively
large pattern element groupings over a range of nip pressures
between the pattern surfaces and the anvil roll. In generating the
data represented in FIG. 20, a 15 gsm polypropylene nonwoven
substrate was bonded to a 12 gsm polypropylene nonwoven substrate
with oval shaped, relatively small, pattern element groupings
(Inventive Nubs 116). In addition, a 15 gsm polypropylene nonwoven
substrate was bonded to a 12 gsm polypropylene nonwoven substrate
with oval shaped, relatively large, pattern element groupings
(Control Nubs 117). FIG. 21A illustrates the pattern element
orientation of the Inventive Nubs on a pattern roll in the machine
direction MD and cross direction CD. And FIG. 21B illustrates the
pattern element orientation of the Control Nubs on a pattern roll
in the machine direction MD and cross direction CD.
TABLE-US-00001 TABLE 1 MD CD Distance Distance Pattern between
Between Element Major Minor Pattern Pattern Grouping Axis Axis
Surfaces Surfaces Inventive 1.27 mm 0.56 mm 0.31 mm 0.31 mm Nubs
Control 2.18 mm 1.40 mm 3.54 mm 1.82 mm Nubs
[0064] Table 1 above provides additional dimensional information
about the oval-shaped Inventive Nub Grouping and the Control Nub
Grouping used to generate the data illustrated in FIG. 20. The
nonwoven substrates were bonded to each other with the Inventive
Nubs and Control Nubs at various nip pressures between pattern
surface and the anvil roll. The Average Peak Bond Strengths of the
bonds generated at the various nip pressures were then measured
according to the Peel Strength Test Method herein.
[0065] It is to be appreciated that bonds 142 formed with the
methods and apparatuses herein may have regions of varying
thicknesses or calipers. As shown in FIGS. 12-14, the discrete bond
142 includes a first surface 170 opposite a second surface 172. A
such, the bond may have: a first thickness, C.sub.1; between the
first surface 170 and the second surface 172 in the membrane
regions 164; a second thickness, C.sub.2; between the first surface
170 and the second surface 172 in the outer grommet region 166; and
a third thickness, C.sub.3; between the first surface 170 and the
second surface 172 in the gap grommet region 168. In some
embodiments, the second thickness, C.sub.2, and the third
thickness, C.sub.3, may both be greater than the first thickness,
C.sub.1, and in some embodiments, the second thickness, C.sub.2,
may also be greater than the third thickness, C.sub.3. In other
embodiments, the second thickness, C.sub.2, may be the same as or
less than the third thickness, C.sub.3. It is also to be
appreciated that bonds 142 formed with the methods and apparatuses
herein may have varying regions of different basis weights. For
example, with continued reference to
[0066] FIGS. 12-14, the membrane region 164 may have a first basis
weight, BW.sub.1; the outer grommet region 166 may have a second
basis weight, BW.sub.2; and the gap grommet region 168 may have a
third basis weight, BW.sub.3. In some embodiments, the second basis
weight, BW.sub.2, and the third basis weight, BW.sub.3, may both be
greater than the first basis weight, BW.sub.1., and in some
embodiments, the second basis weight, BW.sub.2, may also be greater
than the third basis weight, BW.sub.3. In other embodiments, the
second basis weight, BW.sub.2, may be the same as or less than the
third basis weight, BW.sub.3.
[0067] It is also to be appreciated that bonds 142 formed with the
methods and apparatuses herein may have varying regions of
different opacities. For example, the membrane regions 164 may
define a first opacity; the outer grommet region 166 may define a
second opacity; and the gap grommet region 168 may define a third
opacity. In some embodiments, the second and third opacities are
greater than the first opacity.
[0068] It is to be appreciated that bonds having various different
characteristics may be formed with the apparatuses and methods
herein. For example, in some embodiments wherein the bond 142 is
formed by compressing two substrates between the pattern surface
118 and a relatively smooth outer circumferential surface 114 of an
anvil 110, the first, second, and third regions of the bond may
protrude from the respective surfaces 170, 172 by different
distances. For example, as shown in FIG. 14, the outer grommet
region 166 defines a first maximum protrusion height, PH.sub.1A,
with respect to the first surface 170 and defines a second maximum
protrusion height, PH.sub.2A, with respect to the second surface
172. In some embodiments, the first maximum protrusion height,
PH.sub.1A, is greater than the second maximum protrusion height,
PH.sub.2A. In addition, the bond may be configured such that the
gap grommet region 168 defines a first maximum protrusion height,
PH.sub.1B, with respect to the first surface 170 and defines a
second maximum protrusion height, PH.sub.2B, with respect to the
second surface 172. In some embodiments, the first maximum
protrusion height, PH.sub.1B, is greater than the second maximum
protrusion height, PH.sub.2B. When using the bonding apparatuses
and methods herein to make absorbent articles, such as diapers for
example, the bonds may be positioned on the article such that the
bond surfaces having relatively higher protrusion heights face away
from the wearer of the article.
[0069] It is to be appreciated that the bonding apparatus 100 may
also be configured in various different ways. For example,
different types of motor arrangements may be used to rotate the
pattern roll 106 and anvil roll 110. For example, the pattern roll
106 and the anvil roll 110 may be driven independently with two
independent motors. In addition, the nip pressure between pattern
surface and the anvil roll may be generated in various ways. For
example, as previously mentioned, the pattern roll may be biased
toward anvil roll; the anvil roll may be biased toward the pattern
roll; or the pattern and anvil rolls may be biased toward each
other. The biasing of the rolls may be accomplished in various
ways, such as described for example in U.S. Pat. No. 4,854,984. In
some embodiments, the bonding apparatus 100 is configured to define
a nip pressure above 60,000 PSI between the pattern surface 118 and
the anvil roll 110. In some embodiments, the bonding apparatus 100
is configured to define a nip pressure from about 40,000 PSI to
about 60,000 PSI between the pattern surface 118 and the anvil roll
110. In some embodiments, the bonding apparatus 100 is configured
to define a nip pressure of about 40,000 PSI between the pattern
surface 118 and the anvil roll 110. In some embodiments, the
bonding apparatus 100 is configured to define a nip pressure of
about 50,000 PSI between the pattern surface 118 and the anvil roll
110. In some embodiments, the bonding apparatus 100 is configured
to define a nip pressure of about 60,000 PSI between the pattern
surface 118 and the anvil roll 110. It is also to be appreciated
that the pattern roll and/or the anvil roll may be heated.
[0070] It is to be appreciated that the apparatuses and methods
herein can be used to bond various types of substrates together.
For example, in some embodiments the apparatus may used to bond
nonwoven substrates, such as for example, polypropylene nonwoven,
polyethylene film, bi-component nonwoven or film, polyethylene
terephthalate nonwoven or film. In some embodiments, the
apparatuses and methods herein may be used to bond a substrate
which includes a mixture of cellulosic fibers and polyethylene or
polyethylene-polypropylene bicomponent fibers or particulate. In
some embodiments, the substrates may have a basis weight of about 6
gsm to about 100 gsm. Other types of substrates can be sandwiched
in between two layers of nonwovens or films.
[0071] As previously mentioned, the bonding apparatuses and methods
herein may used to bond various types of components used in the
manufacture of different types of absorbent articles. To help
provide additional context to the previous discussion of the
process and apparatus embodiments, the following provides a general
description of absorbent articles in the form of diapers that
include components may be bonded with the methods and apparatuses
disclosed herein.
[0072] For the purposes of a specific illustration, FIGS. 15 and
16A show an example of a diaper pant 300 that may be assembled in
accordance with the apparatuses and methods disclosed herein. In
particular, FIG. 15 shows a perspective view of a diaper pant 300
in a pre-fastened configuration, and FIG. 16A shows a plan view of
the diaper pant 300 with the portion of the diaper that faces away
from a wearer oriented toward the viewer. The diaper pant 300 shown
in FIGS. 15 and 16A includes a chassis 302 and a ring-like elastic
belt 304. As discussed below in more detail, a first elastic belt
306 and a second elastic belt 308 are connected together to form
the ring-like elastic belt 304.
[0073] With continued reference to FIG. 16A, the chassis 302
includes a first waist region 316, a second waist region 318, and a
crotch region 320 disposed intermediate the first and second waist
regions. The first waist region 316 may be configured as a front
waist region, and the second waist region 318 may be configured as
back waist region. In some embodiments, the length of each of the
front waist region, back waist region, and crotch region may be 1/3
of the length of the absorbent article 300. The diaper 300 may also
include a laterally extending front waist edge 321 in the front
waist region 316 and a longitudinally opposing and laterally
extending back waist edge 322 in the back waist region 318. To
provide a frame of reference for the present discussion, the diaper
300 and chassis 302 of FIG. 16A are shown with a longitudinal axis
324 and a lateral axis 326. In some embodiments, the longitudinal
axis 324 may extend through the front waist edge 321 and through
the back waist edge 322. And the lateral axis 326 may extend
through a first longitudinal or right side edge 328 and through a
midpoint of a second longitudinal or left side edge 330 of the
chassis 302.
[0074] As shown in FIGS. 15 and 16A, the diaper pant 300 may
include an inner, body facing surface 332, and an outer, garment
facing surface 334. The chassis 302 may include a backsheet 336 and
a topsheet 338. The chassis 302 may also include an absorbent
assembly 340, including an absorbent core 342, disposed between a
portion of the topsheet 338 and the backsheet 336. As discussed in
more detail below, the diaper 300 may also include other features,
such as leg elastics and/or leg cuffs to enhance the fit around the
legs of the wearer.
[0075] As shown in FIG. 16A, the periphery of the chassis 302 may
be defined by the first longitudinal side edge 328, a second
longitudinal side edge 330, a first laterally extending end edge
344 disposed in the first waist region 316, and a second laterally
extending end edge 346 disposed in the second waist region 318.
Both side edges 328 and 330 extend longitudinally between the first
end edge 344 and the second end edge 346. As shown in FIG. 16A, the
laterally extending end edges 344 and 346 are located
longitudinally inward from the laterally extending front waist edge
321 in the front waist region 316 and the laterally extending back
waist edge 322 in the back waist region 318. When the diaper pant
300 is worn on the lower torso of a wearer, the front waist edge
321 and the back waist edge 322 of the chassis 302 may encircle a
portion of the waist of the wearer. At the same time, the chassis
side edges 328 and 330 may encircle at least a portion of the legs
of the wearer. And the crotch region 320 may be generally
positioned between the legs of the wearer with the absorbent core
342 extending from the front waist region 316 through the crotch
region 320 to the back waist region 318.
[0076] It is to also be appreciated that a portion or the whole of
the diaper 300 may also be made laterally extensible. The
additional extensibility may help allow the diaper 300 to conform
to the body of a wearer during movement by the wearer. The
additional extensibility may also help, for example, the user of
the diaper 300, including a chassis 302 having a particular size
before extension, to extend the front waist region 316, the back
waist region 318, or both waist regions of the diaper 300 and/or
chassis 302 to provide additional body coverage for wearers of
differing size, i.e., to tailor the diaper to an individual wearer.
Such extension of the waist region or regions may give the
absorbent article a generally hourglass shape, so long as the
crotch region is extended to a relatively lesser degree than the
waist region or regions, and may impart a tailored appearance to
the article when it is worn.
[0077] As previously mentioned, the diaper pant 300 may include a
backsheet 336. The backsheet 336 may also define the outer surface
334 of the chassis 302. The backsheet 336 may be impervious to
fluids (e.g., menses, urine, and/or runny feces) and may be
manufactured from a thin plastic film, although other flexible
liquid impervious materials may also be used. The backsheet 336 may
prevent the exudates absorbed and contained in the absorbent core
from wetting articles which contact the diaper 300, such as
bedsheets, pajamas and undergarments. The backsheet 336 may also
comprise a woven or nonwoven material, polymeric films such as
thermoplastic films of polyethylene or polypropylene, and/or a
multi-layer or composite materials comprising a film and a nonwoven
material (e.g., having an inner film layer and an outer nonwoven
layer). The backsheet may also comprise an elastomeric film. An
example backsheet 336 may be a polyethylene film having a thickness
of from about 0.012 mm (0.5 mils) to about 0.051 mm (2.0 mils).
Exemplary polyethylene films are manufactured by Clopay Corporation
of Cincinnati, Ohio, under the designation BR-120 and BR-121 and by
Tredegar Film Products of Terre Haute, Ind., under the designation
XP-39385. The backsheet 336 may also be embossed and/or
matte-finished to provide a more clothlike appearance. Further, the
backsheet 336 may permit vapors to escape from the absorbent core
(i.e., the backsheet is breathable) while still preventing exudates
from passing through the backsheet 336. The size of the backsheet
336 may be dictated by the size of the absorbent core 342 and/or
particular configuration or size of the diaper 300.
[0078] Also described above, the diaper pant 300 may include a
topsheet 338. The topsheet 338 may also define all or part of the
inner surface 332 of the chassis 302. The topsheet 338 may be
compliant, soft feeling, and non-irritating to the wearer's skin.
It may be elastically stretchable in one or two directions.
Further, the topsheet 338 may be liquid pervious, permitting
liquids (e.g., menses, urine, and/or runny feces) to penetrate
through its thickness. A topsheet 338 may be manufactured from a
wide range of materials such as woven and nonwoven materials;
apertured or hydroformed thermoplastic films; apertured nonwovens,
porous foams; reticulated foams; reticulated thermoplastic films;
and thermoplastic scrims. Woven and nonwoven materials may comprise
natural fibers such as wood or cotton fibers; synthetic fibers such
as polyester, polypropylene, or polyethylene fibers; or
combinations thereof. If the topsheet 338 includes fibers, the
fibers may be spunbond, carded, wet-laid, meltblown,
hydroentangled, or otherwise processed as is known in the art.
[0079] Topsheets 338 may be selected from high loft nonwoven
topsheets, apertured film topsheets and apertured nonwoven
topsheets. Apertured film topsheets may be pervious to bodily
exudates, yet substantially non-absorbent, and have a reduced
tendency to allow fluids to pass back through and rewet the
wearer's skin. Exemplary apertured films may include those
described in U.S. Pat. Nos. 5,628,097; 5,916,661; 6,545,197; and
U.S. Pat. No. 6,107,539.
[0080] As mentioned above, the diaper pant 300 may also include an
absorbent assembly 340 that is joined to the chassis 302. As shown
in FIG. 16A, the absorbent assembly 340 may have a laterally
extending front edge 348 in the front waist region 316 and may have
a longitudinally opposing and laterally extending back edge 350 in
the back waist region 318. The absorbent assembly may have a
longitudinally extending right side edge 352 and may have a
laterally opposing and longitudinally extending left side edge 354,
both absorbent assembly side edges 352 and 354 may extend
longitudinally between the front edge 348 and the back edge 350.
The absorbent assembly 340 may additionally include one or more
absorbent cores 342 or absorbent core layers. The absorbent core
342 may be at least partially disposed between the topsheet 338 and
the backsheet 336 and may be formed in various sizes and shapes
that are compatible with the diaper. Exemplary absorbent structures
for use as the absorbent core of the present disclosure are
described in U.S. Pat. Nos. 4,610,678; 4,673,402; 4,888,231; and
U.S. Pat. No. 4,834,735.
[0081] Some absorbent core embodiments may comprise fluid storage
cores that contain reduced amounts of cellulosic airfelt material.
For instance, such cores may comprise less than about 40%, 30%,
20%, 10%, 5%, or even 1% of cellulosic airfelt material. Such a
core may comprises primarily absorbent gelling material in amounts
of at least about 60%, 70%, 80%, 85%, 90%, 95%, or even about 100%,
where the remainder of the core comprises a microfiber glue (if
applicable). Such cores, microfiber glues, and absorbent gelling
materials are described in U.S. Pat. Nos. 5,599,335; 5,562,646;
5,669,894; and U.S. Pat. No. 6,790,798 as well as U.S. Patent
Publication Nos. 2004/0158212 and 2004/0097895.
[0082] As previously mentioned, the diaper 300 may also include
elasticized leg cuffs 356. It is to be appreciated that the leg
cuffs 356 can be and are sometimes also referred to as leg bands,
side flaps, barrier cuffs, elastic cuffs or gasketing cuffs. The
elasticized leg cuffs 356 may be configured in various ways to help
reduce the leakage of body exudates in the leg regions. Example leg
cuffs 356 may include those described in U.S. Pat. Nos. 3,860,003;
4,909,803; 4,695,278; 4,795,454; 4,704,115; 4,909,803; and U.S.
Patent Publication No. 2009/0312730A1; and U.S. patent application
Ser. No. 13/435,503, entitled "METHODS AND APPARATUSES FOR MAKING
LEG CUFFS FOR ABSORBENT ARTICLES", filed on Mar. 30, 2012.
[0083] As mentioned above, diaper pants may be manufactured with a
ring-like elastic belt 304 and provided to consumers in a
configuration wherein the front waist region 316 and the back waist
region 318 are connected to each other as packaged, prior to being
applied to the wearer. As such, diaper pants may have a continuous
perimeter waist opening 310 and continuous perimeter leg openings
312 such as shown in FIG. 15.
[0084] As previously mentioned, the ring-like elastic belt 304 is
defined by a first elastic belt 306 connected with a second elastic
belt 308. As shown in FIG. 16A, the first elastic belt 306 defines
first and second opposing end regions 306a, 306b and a central
region 306c, and the second elastic 308 belt defines first and
second opposing end regions 308a, 308b and a central region
308c.
[0085] The central region 306c of the first elastic belt is
connected with the first waist region 316 of the chassis 302, and
the central region 308c of the second elastic belt 308 is connected
with the second waist region 316 of the chassis 302. As shown in
FIG. 15, the first end region 306a of the first elastic belt 306 is
connected with the first end region 308a of the second elastic belt
308 at first side seam 378, and the second end region 306b of the
first elastic belt 306 is connected with the second end region 308b
of the second elastic belt 308 at second side seam 380 to define
the ring-like elastic belt 304 as well as the waist opening 310 and
leg openings 312. As discussed in more detail below, bonding
apparatuses 100 herein may be used to create discrete bond regions
142 that connect first and second elastic belts 306, 308 together
at the first and second side seams 378, 380.
[0086] As shown in FIGS. 16A, 17A, and 17B, the first elastic belt
306 also defines an outer lateral edge 307a and an inner lateral
edge 307b, and the second elastic belt 308 defines an outer lateral
edge 309a and an inner lateral edge 309b. The outer lateral edges
307a, 307b may also define the front waist edge 320 and the
laterally extending back waist edge 322. The first elastic belt and
the second elastic belt may also each include an outer, garment
facing layer 362 and an inner, wearer facing layer 364. It is to be
appreciated that the first elastic belt 306 and the second elastic
belt 308 may comprise the same materials and/or may have the same
structure. In some embodiments, the first elastic belt 306 and the
second elastic belt may comprise different materials and/or may
have different structures. It should also be appreciated that the
first elastic belt 306 and the second elastic belt 308 may be
constructed from various materials. For example, the first and
second belts may be manufactured from materials such as plastic
films; apertured plastic films; woven or nonwoven webs of natural
materials (e.g., wood or cotton fibers), synthetic fibers (e.g.,
polyolefins, polyamides, polyester, polyethylene, or polypropylene
fibers) or a combination of natural and/or synthetic fibers; or
coated woven or nonwoven webs. In some embodiments, the first and
second elastic belts include a nonwoven web of synthetic fibers,
and may include a stretchable nonwoven. In other embodiments, the
first and second elastic belts include an inner hydrophobic,
non-stretchable nonwoven material and an outer hydrophobic,
non-stretchable nonwoven material.
[0087] The first and second elastic belts 306, 308 may also each
include belt elastic material interposed between the outer layer
362 and the inner layer 364. The belt elastic material may include
one or more elastic elements such as strands, ribbons, or panels
extending along the lengths of the elastic belts. As shown in FIGS.
16A, 17A, and 17B, the belt elastic material may include a
plurality of elastic strands 368 which may be referred to herein as
outer, waist elastics 370 and inner, waist elastics 372. As shown
in FIG. 16A, the elastic strands 368 continuously extend laterally
between the first and second opposing end regions 306a, 306b of the
first elastic belt 306 and between the first and second opposing
end regions 308a, 308b of the second elastic belt 308. In some
embodiments, some elastic strands 368 may be configured with
discontinuities in areas, such as for example, where the first and
second elastic belts 306, 308 overlap the absorbent assembly 340.
In some embodiments, the elastic strands 368 may be disposed at a
constant interval in the longitudinal direction. In other
embodiments, the elastic strands 368 may be disposed at different
intervals in the longitudinal direction. The belt elastic material
in a stretched condition may be interposed and joined between the
uncontracted outer layer and the uncontracted inner layer. When the
belt elastic material is relaxed, the belt elastic material returns
to an unstretched condition and contracts the outer layer and the
inner layer. The belt elastic material may provide a desired
variation of contraction force in the area of the ring-like elastic
belt.
[0088] It is to be appreciated that the chassis 302 and elastic
belts 306, 308 may be configured in different ways other than as
depicted in FIG. 16A. For example, FIG. 16B shows a plan view of a
diaper pant 300 having the same components as described above with
reference to FIG. 16A, except the first laterally extending end
edge 344 of the chassis 302 is aligned along and coincides with the
outer lateral edge 307a of the first elastic belt 306, and the
second laterally extending end edge 346 is aligned along and
coincides with the outer lateral edge 309a of the second belt
308.
[0089] As previously mentioned, the apparatuses and methods
according to the present disclosure may be utilized to assemble
various components of diapers 300. For example, FIG. 18 shows a
schematic view of a converting apparatus 500 adapted to manufacture
pant diapers 300. The method of operation of the converting
apparatus 500 may be described with reference to the various
components of pant diapers 300 described above and shown in FIGS.
15 and 16A. Although the following methods are provided in the
context of the diaper 300 shown in FIGS. 15 and 16A, it is to be
appreciated that various embodiments of diaper pants can be
manufactured according to the methods disclosed herein, such as for
example, the absorbent articles disclosed in U.S. Pat. No.
7,569,039 and; U.S. Patent Publication Nos. 2005/0107764A1,
US2012/0061016A1, and US2012/0061015A1, which are all hereby
incorporated by reference herein.
[0090] As described in more detail below, the converting apparatus
500 shown in FIG. 18 operates to advance discrete chassis 302 along
a machine direction MD such that the lateral axis of each chassis
302 is parallel with the machine direction, and wherein the chassis
302 are spaced apart from each other along the machine direction.
Opposing waist regions 316, 318 of the spaced apart chassis 302 are
then connected with continuous lengths of advancing first and
second elastic belt substrates 606, 608. The chassis 302 are then
folded along the lateral axis to bring the first and second elastic
belt substrates 606, 608 into a facing relationship, and the first
and second elastic belt substrates are connected together along
regions 536 intermittently spaced along the machine direction,
wherein each region 536 may include one or more discrete bond sites
142. And the elastic belt substrates 606, 608 are cut along the
regions 536 to create discrete diapers 300, such as shown in FIG.
15. As shown in FIGS. 18 and 17A, a continuous length of chassis
assemblies 502 are advanced in a machine direction MD to a carrier
apparatus 508 and cut into discrete chassis 302 with knife roll
506. The continuous length of chassis assemblies may include
absorbent assemblies 340 sandwiched between topsheet material 338
and backsheet material 336, leg elastics, barrier leg cuffs and the
like. A portion of the chassis assembly is cut-away to show a
portion of the topsheet material 338 and an absorbent assembly
340.
[0091] After the discrete absorbent chassis 302 are cut by the
knife roll 506, the carrier apparatus 508 rotates and advances the
discrete chassis 302 in the machine direction MD in the orientation
shown in FIG. 19B1, wherein the longitudinal axis 324 of the
chassis 302 is generally parallel with the machine direction MD.
While the chassis 302 shown in FIG. 19B1 is shown with the second
laterally extending end edge 346 as a leading edge and the first
laterally extending end edge 344 as the trailing edge, it is to be
appreciated that in other embodiments, the chassis 302 may be
advanced in other orientations. For example, the chassis may be
oriented such that the second laterally extending end edge 346 is a
trailing edge and the first laterally extending end edge 344 is a
leading edge. The carrier apparatus 508 also rotates while at the
same time changing the orientation of the advancing chassis 302.
The carrier apparatus 508 may also change the speed at which the
chassis 302 advances in the machine direction MD. It is to be
appreciated that various forms of carrier apparatuses may be used
with the methods herein, such as for example, the carrier
apparatuses disclosed in U.S. Pat. No. 7,587,966. FIG. 19B2 shows
the orientation of the chassis 302 on the carrier apparatus 508
while advancing in the machine direction. More particularly, FIG.
19B2 shows the chassis 302 with the lateral axis 326 of the chassis
302 generally parallel with the machine direction MD, and wherein
the second longitudinal side edge 330 is the leading edge and the
first longitudinal side edge 328 is the trailing edge.
[0092] As discussed below with reference to FIGS. 18, 19C, 19D,
19E, and 19F, the chassis 302 are transferred from the carrier
apparatus 508 and combined with advancing, continuous lengths of
belt substrates 606, 608, which are subsequently cut to form first
and second elastic belts 306, 308 on diapers 300.
[0093] With reference to FIGS. 17 and 19C, the chassis 302 are
transferred from the carrier apparatus 508 to a nip 516 between the
carrier apparatus 508 and a carrier apparatus 518 where the chassis
302 is combined with continuous lengths of advancing front belt 606
and back belt 608 substrate material. The front belt substrate
material 606 and the back belt substrate material 608 each define a
wearer facing surface 512 and an opposing garment facing surface
514. The wearer facing surface 512 of the first belt substrate 606
may be combined with the garment facing surface 334 of the chassis
302 along the first waist region 316, and the wearer facing surface
512 of the second belt substrate 608 may be combined with the
garment facing surface 334 of the chassis 302 along the second
waist region 318. As shown in FIG. 18, adhesive 520 may be
intermittently applied to the wearer facing surface 512 of the
first and second belt substrates 606, 608 before combining with the
discrete chassis 302 at the nip 516 between roll 518 and the
carrier apparatus 508.
[0094] With reference to FIGS. 18 and 19D, a continuous length of
absorbent articles 600 are defined by multiple discrete chassis 302
spaced from each other along the machine direction MD and connected
with each other by the second belt substrate 608 and the first belt
substrate 606. As shown in FIG. 18, the continuous length of
absorbent articles 600 advances from the nip 516 to a folding
apparatus 500. At the folding apparatus 500, each chassis 302 is
folded in the cross direction CD along a lateral axis 326 to place
the first waist region 316, and specifically, the inner, body
facing surface 332 into a facing, surface to surface orientation
with the inner, body surface 332 of the second waist region 318.
The folding of the chassis also positions the wearer facing surface
512 of the second belt substrate 608 extending between each chassis
302 in a facing relationship with the wearer facing surface 512 of
the first belt substrate 606 extending between each chassis 302. As
shown in FIGS. 18, 19D, and 19E, the folded discrete chassis 302
connected with the first and second belt substrates 606, 608 are
advanced from the folding apparatus 500 to a bonder apparatus 100,
such as described above. The bonder apparatus 100 operates to bond
an overlap area 362, thus creating discrete bond sites 142. The
overlap area 362 includes a portion of the second belt substrate
608 extending between each chassis 302 and a portion of the first
belt substrate 606 extending between each chassis 302. As shown in
FIGS. 18 and 19F, a continuous length of absorbent articles are
advanced from the bonder 100 to a knife roll 538 where the regions
536 are cut into along the cross direction to create a first side
seam 378 on an absorbent article 300 and a second side seam 380 on
a subsequently advancing absorbent article.
[0095] Although the absorbent article is described as having a
first and second belt substrate, it is to be appreciated that the
absorbent article may have only one belt substrate. Further, it is
to be appreciated that the chassis and belt substrate of the
absorbent article may be one continuous substrate such that the
overlap area is formed from the same substrate. As such, the bonder
apparatus may operate to bond a continuous substrate at an overlap
area to form one or more discrete bond sites.
[0096] Although the apparatuses and methods have been described in
the context of the diapers 300 shown in FIGS. 15, 16A, and 16B, it
is to be appreciated that the methods and apparatuses herein may be
used to assemble and bond various substrates and/or elastic
laminates that can be used with various process configurations
and/or absorbent articles, such as for example, disclosed in U.S.
Pat.No. 7,569,039; U.S. Patent Publication Nos. US2005/0107764A1,
US2012/0061016A1, and US2012/0061015A1; U.S. patent application
Ser. No. 13/434,984, filed on Mar. 30, 2012; U.S. patent
application Ser. No. 13/435,036, filed on Mar. 30, 2012; U.S.
patent application Ser. No. 13/435,063, filed on Mar. 30, 2012;
U.S. patent application Ser. No. 13/435,247, filed on Mar. 30,
2012; and U.S. patent application Ser. No. 13/435,503, filed on
Mar. 30, 2012, all of which are incorporated by reference herein.
For example, the bonding apparatuses and methods herein can be used
to apply tack-down bonds on leg cuffs, such as described in U.S.
patent application Ser. No. 13/435,503, entitled "METHODS AND
APPARATUSES FOR MAKING LEG CUFFS FOR ABSORBENT ARTICLES", filed on
Mar. 30, 2012.
[0097] In the context of the previous discussion, the apparatuses
100 and methods herein may be used to provide for the application
of bonds 142 in patterns to substrates and components during the
manufacture of an absorbent article. For example, bonds 142 may be
applied in various patterns to portions of any of the topsheet,
backsheet, absorbent core, leg cuffs, waist feature, ears, and
fastening elements during the manufacture of an absorbent article.
In some instances, the adhesive may be used in combination with the
bonding methods herein.
Peel Strength Test Method
[0098] Bond Strength is measured using a 180.degree. T-peel test on
a constant rate of extension tensile tester with computer interface
(a suitable instrument is the MTS Model Q-Test/1 using Testworks
4.0 Software, as available from MTS Systems Corp., Eden Prairie,
Minn.) using a load cell for which the forces measured are within
10% to 90% of the limit of the cell. Both the movable (upper) and
stationary (lower) pneumatic jaws are fitted with smooth stainless
steel faced grips, 25.4 mm in height and wider than the width of
the test specimen. Air pressure supplied to the jaws is sufficient
to prevent sample slippage. All testing is performed in a
conditioned room maintained at about 23.degree. C..+-.2 C..degree.
and about 50.degree. C..+-.2 C..degree. relative humidity.
[0099] Condition the samples at 23.+-.2.degree. C. and 50%.+-.2%
relative humidity for at least 24 hours prior to testing. Identify
the bond site to be tested. The test specimen consists of the bond
and the two material layers which are bonded together. Using a
razor knife or scissors cut the specimen 25.4 mm.+-.0.1 mm in the
dimension parallel to the bond, and preferably 50.8 mm in the
dimension perpendicular to and centered on the bond. If a 50.8 mm
perpendicular length cannot be harvested from the article, attach
leads made from adhesive tape (e.g., duct tape) to the specimen for
use to secure it in the tensile tester's grip faces.
[0100] Program the tensile tester to perform an extension test,
collecting force and extension data at an acquisition rate of 50 Hz
as the crosshead raises at a rate of 304 mm/min until the two
layers are separated.
[0101] Set the gage length to 25.4 mm.+-.0.1 mm and zero the
crosshead position. Referring to FIG. 22, position the end of the
first layer (or attached leader) 702 within the upper grip faces.
Align the specimen 700 vertically with the bond site 703 centered
between the upper and lower grip faces and close the upper grip
faces. With the specimen hanging downward and not touching the
bottom fixture, zero the load cell. Position the second layer (or
attached leader) 704 within the lower grip faces and close. The
specimen should be under enough tension to eliminate any slack, but
less than 0.05 N of force on the load cell.
[0102] Start the test and collect data. From the resulting Force
(N) versus Extension (mm) curve, calculate the Maximum Peak Force
(N). Calculate the Bond Strength (N/m) as the Peak Force (N)
divided by the specimen width (m) and record to the nearest 0.1
N/m.
[0103] Repeat the test on a total of ten substantially identical
articles selecting the corresponding test site on each article.
Report the average Bond Strength (N/m) to the nearest 0.1 N/m.
End of Peel Strength Test Method
[0104] This application is a divisional of U.S. application Ser.
No. 14/301,416, filed on Jun. 11, 2014, which claims the benefit of
U.S. Provisional Application No. 61/836,745, filed Jun. 19, 2013,
the entireties of which are incorporated by reference herein.
[0105] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm."
[0106] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document is not an admission that it
is prior art with respect to any invention disclosed or claimed
herein or that it alone, or in any combination with any other
reference or references, teaches, suggests or discloses any such
invention. Further, to the extent that any meaning or definition of
a term in this document conflicts with any meaning or definition of
the same term in a document incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0107] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *