U.S. patent application number 12/858619 was filed with the patent office on 2012-02-16 for absorbent article including a formed fibrous article.
Invention is credited to Marco Antonio Alkmin, Livea Fujita Barbosa, Jose Francisco Cau, Jose Manoel Soares Coutinho, Ivair Luiz Duarte, Reinaldo Lourenco Faria, Francisco J. V. Hernandez, Manuela Leonel Martines, Francisco Antonio Rimoli, Francisco Savastano Neto, Alexandre Teixeira Yamashita.
Application Number | 20120041405 12/858619 |
Document ID | / |
Family ID | 45563944 |
Filed Date | 2012-02-16 |
United States Patent
Application |
20120041405 |
Kind Code |
A1 |
Alkmin; Marco Antonio ; et
al. |
February 16, 2012 |
ABSORBENT ARTICLE INCLUDING A FORMED FIBROUS ARTICLE
Abstract
The present invention generally relates to a method and
apparatus for a making a formed fibrous article and more
specifically to method and apparatus for making a formed fibrous
article useful as an absorbent core structure in a disposable
sanitary article such as a sanitary napkin, panty liner, diaper or
the like. The present invention also relates to a disposable
sanitary article including a formed fibrous article according to
the present invention as a core structure thereof.
Inventors: |
Alkmin; Marco Antonio; (Sao
Jose dos Campos, BR) ; Barbosa; Livea Fujita; (Sao
Jose dos Campos, BR) ; Cau; Jose Francisco; (Sao Jose
dos Campos, BR) ; Coutinho; Jose Manoel Soares;
(Taubate, BR) ; Duarte; Ivair Luiz; (Jardim
Florida Jacarei, BR) ; Faria; Reinaldo Lourenco; (Sao
Jose dos Campos, BZ) ; Hernandez; Francisco J. V.;
(Sao Jose dos Campos, BR) ; Martines; Manuela Leonel;
(Sao Jose dos Campos, BR) ; Rimoli; Francisco
Antonio; (Mogi das Cruzes, BR) ; Savastano Neto;
Francisco; (Taubate, BR) ; Yamashita; Alexandre
Teixeira; (Sao Jose dos Campos, BR) |
Family ID: |
45563944 |
Appl. No.: |
12/858619 |
Filed: |
August 18, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12855175 |
Aug 12, 2010 |
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12858619 |
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Current U.S.
Class: |
604/383 ;
264/232; 428/157; 428/166; 604/378 |
Current CPC
Class: |
Y10T 428/24562 20150115;
A61F 13/15626 20130101; Y10T 428/24488 20150115 |
Class at
Publication: |
604/383 ;
264/232; 428/166; 428/157; 604/378 |
International
Class: |
A61F 13/51 20060101
A61F013/51; B32B 5/02 20060101 B32B005/02; B32B 3/02 20060101
B32B003/02; B29C 71/00 20060101 B29C071/00 |
Claims
1. An absorbent article comprising: a liquid permeable cover layer;
a liquid impermeable barrier layer; a formed fibrous article
arranged between the cover layer and the barrier layer, wherein the
formed fibrous includes a planar portion and a first and second
raised area extending upwardly from the planar portion, a region
located between the first raised area and the second raised area,
the planar portion and the first and second raised areas being both
formed from a common material composition having a constant basis
weight, the planar portion having a different thickness and density
than each of the first raised area and second raised area; wherein
the cover layer extends over the first raised area, the second
raised area, and region located between the first raised area and
the second raised area; and wherein a portion of the cover layer
extending over the region located between the first raised area and
the second raised area is arranged in spaced relationship to the
formed fibrous article.
2. The absorbent article according to claim 1, wherein the fibrous
article further includes a centrally extending pin embossed area
extending along a longitudinally extending central axis of the
article.
3. The absorbent article according to claim 2, wherein the fibrous
article includes an area that is free of pin embossing.
4. The absorbent article according to claim 3, wherein the formed
fibrous article is formed from a single material layer.
5. The absorbent article according to claim 4, wherein the region
located between the first raised area and the second raised area is
pin embossed to include a plurality of depressions.
6. The absorbent article according to claim 5, wherein the formed
fibrous article is formed by a method including the steps of:
forming a formed fibrous article having a three dimensional
profile; and pin-calendering the fibrous article in a pin
calendering station between a first roll and a second roll, wherein
the fibrous article is conveyed through a nip defined between the
first roll and the second roll without the use of a carrier
layer.
7. The absorbent article according to claim 6, wherein the formed
fibrous article is formed by a method including the steps of:
forming the formed fibrous article; and passing the formed fibrous
article through a calendering station to thereby provide the formed
fibrous article with the three dimensional profile.
8. The absorbent article according to claim 7, wherein the
calendering station includes a vacuum roll and an opposed calender
roll.
9. The absorbent article according to claim 8, wherein the step of
forming the fibrous article comprises the steps of: providing
fibrous pulp, maintaining the fibrous pulp in a chamber, mounting a
mold to a rotating forming drum, rotating the mold on the rotating
forming drum until the mold is arranged in communication with the
chamber, and drawing the fibrous pulp into the mold to thereby form
the fibrous article.
10. The absorbent article according to claim 9, wherein the first
roll comprises a vacuum roll and the second roll comprises a pin
calender roll.
11. The absorbent article according to claim 10, wherein a surface
of the vacuum roll includes a plurality of holes and the pin
calender roll includes a plurality of pins extending outwardly from
a surface of the roll.
12. The absorbent article according to claim 11, wherein each one
of the plurality of pins is arranged such that it does not overlap
with any of the plurality of holes.
13. The absorbent article according to claim 12, wherein the
fibrous article is formed in the mold and transferred to the
calendering station without the use of a carrier layer.
14. The absorbent article according to claim 13, further
comprising: transferring the fibrous article from the vacuum roll
of the calendering station to the vacuum roll of the pin
calendering station.
15. The absorbent article according to claim 14, wherein the
fibrous article is transferred from the vacuum roll of the
calendering station to the vacuum roll of the pin calendering
station without the use of a carrier layer.
16. The absorbent article according to claim 15, further comprising
transferring the fibrous article from the vacuum wheel of the pin
calendering station to a transfer wheel.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation application of
U.S. patent application Ser. No. 12/866,175, filed Aug. 12, 2010,
priority of which is hereby claimed.
FIELD OF THE INVENTION
[0002] The present invention generally relates to a method and
apparatus for a making a formed fibrous article and more
specifically to method and apparatus for making a formed fibrous
article useful as an absorbent core structure in a disposable
sanitary article such as a sanitary napkin, panty liner, diaper or
the like. The present invention also relates to a disposable
sanitary article including a formed fibrous article according to
the present invention as a core structure thereof.
BACKGROUND OF THE INVENTION
[0003] Various methods for making formed fibrous articles from
fibrous materials such as cellulose or the like are well know to
those of skill in the art. One common method of manufacturing such
formed fibrous articles consists of defiberizing a starting
material and then creating an air-entrained stream of the
defiberized material. The air-entrained defiberized material may be
formed into a formed fibrous article through the use of a porous
mold structure subjected to a vacuum to draw the defiberized
material into the mold.
[0004] It is also known that formed fibrous articles of the type
described above may be subjected to calendering processes to alter
the mechanical and fluid handling properties of such articles. A
calendering process used in the art is commonly referred to as "pin
calendering". Pin calendering employs the use of a plurality of
pins adapted to compress and densify the article.
[0005] A problem associated with pin calendering processes of the
type described above is that such processes typically require that
a "carrier layer" be used during the pin-calendering step. "Carrier
layer" as used herein means any material layer used to support the
formed fibrous article, such as a conveyer belt or an adjacent
material layer such as rolled nonwoven layer or the like. The use
of a carrier layer increases complexity of manufacture. In
addition, if the carrier layer is a layer intended to be
incorporated into the final product, the inclusion of such layer
may increase the cost of the final product and/or undesirably
affect the fluid handling characteristics of the product.
[0006] In view of the above the inventors of the present invention
have discovered, and disclosed herein, a method and apparatus for
making a pin-calendered formed fibrous article that does not
require the use of a carrier layer. Formed fibrous articles
according to the present invention are particularly useful as an
absorbent core structure in a disposable sanitary article such as a
sanitary napkin, panty liner, diaper or the like.
SUMMARY OF THE INVENTION
[0007] In view of the foregoing, the present invention provides an
absorbent article including a liquid permeable cover layer, a
liquid impermeable barrier layer, a formed fibrous article arranged
between the cover layer and the barrier layer, wherein the formed
fibrous includes a planar portion and a first and second raised
area extending upwardly from the planar portion, a region located
between the first raised area and the second raised area, the
planar portion and the first and second raised areas being both
formed from a common material composition having a constant basis
weight, the planar portion having a different thickness and density
than each of the first raised area and second raised area, wherein
the cover layer extends over the first raised area, the second
raised area, and region located between the first raised area and
the second raised area, and wherein a portion of the cover layer
extending over the region located between the first raised area and
the second raised area is arranged in spaced relationship to the
formed fibrous article.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Examples of embodiments of the present invention will now be
described with reference to the drawings, in which:
[0009] FIG. 1 is a side elevation view of an apparatus according to
the present invention;
[0010] FIG. 2 is a detailed perspective view of the forming drum
that forms part of the apparatus according to the present
invention;
[0011] FIG. 3 is a sectional view taken along line 3-3 in FIG.
2;
[0012] FIG. 4 is a detailed perspective view of a portion of the
forming drum shown in FIG. 2;
[0013] FIG. 5 is a side elevation view of the forming drum and a
calendering station that form part of the apparatus according to
the present invention;
[0014] FIG. 6 is a detailed perspective view of the calendering
station shown in FIG. 5, depicting the vacuum roll and calender
roll thereof;
[0015] FIG. 7 is a elevation view of the that portion of the
calendering station calender roll circled in FIG. 6;
[0016] FIG. 8 is a sectional view taken along line 8-8 in FIG.
6;
[0017] FIG. 9 is a detailed perspective view of that portion of the
calendering station vacuum roll circled in FIG. 6;
[0018] FIG. 10 is a perspective view of a formed fibrous article
according to the invention after passing through the calendering
station;
[0019] FIG. 11 is a side elevation view of a pin calendering
station that forms part of the apparatus according to the present
invention;
[0020] FIG. 12 is a detailed perspective view of the pin
calendering station shown in FIG. 11, depicting the vacuum roll and
pin calender roll thereof;
[0021] FIG. 13 is a partially exploded perspective view of the pin
calendering station pin calender roll;
[0022] FIG. 14 is a detailed plan view of that portion of the pin
calender roll circled in FIG. 13;
[0023] FIG. 15 is a sectional view taken along line 15-15 in FIG.
14;
[0024] FIG. 16 is detailed perspective view of that portion of the
pin calender roll circled in FIG. 13;
[0025] FIG. 17 is a sectional view taken along line 17-17 in FIG.
11;
[0026] FIG. 18 is a sectional view taken along line 18-18 in FIG.
12;
[0027] FIG. 19 is a side elevation view of a transfer wheel that
forms part of the apparatus according to the present invention;
[0028] FIG. 20 is a perspective view of the transfer wheel shown in
FIG. 19;
[0029] FIG. 21 is a top plan view of the formed fibrous article
after passing through the pin calendering station;
[0030] FIG. 22 is a detailed perspective view of that portion of
the formed fibrous article circled in FIG. 21;
[0031] FIG. 23 is a perspective view of an absorbent article
according to the present invention with the cover layer and
transfer layer thereof partially broken away;
[0032] FIG. 24 is a sectional view taken along line 24-24 in FIG.
23; and
[0033] FIGS. 25-26 are perspective views of alternate embodiments
of absorbent articles according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0034] Referring to FIGS. 1-9 and 11-20, there is illustrated a
preferred apparatus 10 for making a formed fibrous article 12
according to the method of the present invention.
[0035] As shown in FIG. 1, the apparatus 10 according to the
present invention generally includes a forming drum 14, a
calendering station 16, a pin calendering station 18, and a
transfer wheel 20. Certain details of the apparatus 10, such as
electrical lines, have been omitted from the figures to simplify
the same. However, these features and other basic elements of the
apparatus will be clear to those of skill in the art.
[0036] The formed fibrous article 12, which is depicted during
various stages of the method according to the present invention in
FIGS. 3, 5-6, 8, 10, 12 and 18-22, preferably is formed from
cellulosic fibers, and in a preferred embodiment of the invention,
includes a mixture of cellulosic fibers and superabsorbent polymer.
Cellulosic fibers that can be used in the formed fibrous article 12
are well known in the art and include wood pulp, cotton, flax and
peat moss. Wood pulp is preferred. Both softwood and hardwood
species are useful. Softwood pulps are preferred.
[0037] The fibrous article 12 may also contain any superabsorbent
polymer (SAP), which are well known in the art. For the purposes of
the present invention, the term "superabsorbent polymer" (or "SAP")
refers to materials, which are capable of absorbing and retaining
at least about 10 times their weight in body fluids under a 0.5 psi
pressure. The superabsorbent polymer particles of the invention may
be inorganic or organic crosslinked hydrophilic polymers, such as
polyvinyl alcohols, polyethylene oxides, crosslinked starches, guar
gum, xanthan gum, and the like. The particles may be in the form of
a powder, grains, granules, or fibers. Preferred superabsorbent
polymer particles for use in the present invention are crosslinked
polyacrylates, such as the product offered by Sumitomo Seika
Chemicals Co., Ltd. of Osaka, Japan, under the designation of SA70N
and products offered by Stockhausen Inc.
[0038] The pulp used to form the fibrous article 12 is preferably a
bleached softwood pulp, produced by a Kraft process. As shown in
FIG. 1, the pulp is provided by the manufacturer as a pulp board 22
in rolled form, the roll identified by the reference numeral 24.
The pulp board 22 is conveyed from the roll 24 to a device 26 for
grinding the pulp board 22 into fibrous pulp 28. The fibrous pulp
28 is released from the grinding device 26 into a chamber 30 for
holding the fibrous pulp 28. The apparatus 10 may further
optionally include a device 32 for introducing superabsorbent
polymer into the chamber 30 to thereby form a fibrous pulp and
superabsorbent mixture. Any conventional device suitable for this
purpose, and known to those of skill in the art, may be used for
introducing the superabsorbent into the chamber 30.
[0039] As best seen in FIG. 3, the chamber 30 has a partially open
bottom portion 34 that communicates with the forming drum 14. As
seen in FIG. 1, the forming drum 14 includes a hollow cylinder 15
that is structured and arranged to rotate about a fixed axis 17.
Any conventional means to rotate the cylinder 15, well known to
those of skill in the art, may be used to rotate the cylinder 15.
As shown in FIGS. 1-4, the cylinder 15 has a plurality of molds 36
mounted thereto. As the cylinder 15 rotates, each of the molds 36
are sequentially arranged in communication with the open portion 34
of the chamber 30 to thereby receive fibrous pulp 28 from the
chamber 30. In FIG. 1, the cylinder 15 rotates in a
counterclockwise manner during operation of the apparatus 10.
[0040] As shown in FIGS. 1 and 3, the forming drum 14 further
includes a vacuum chamber 38 arranged within the interior of the
cylinder 15. The vacuum chamber 38 is arranged in a fixed location
relative to the rotating cylinder 15 and is operably coupled to a
vacuum source (not shown). As best seen in FIG. 4, the mold 36
includes a porous screen 40 structure in the shape of the formed
fibrous article 12 to be formed in the mold 36. As the mold 36
passes over the vacuum chamber 38 of the forming drum 14 the vacuum
functions to draw the fibrous pulp 28 from the chamber 30 into the
mold 36 by drawing air through the porous screen 40 of the mold
36.
[0041] As shown in detail in FIG. 4, the mold 36 includes a
nonporous mounting plate portion 42 that surrounds the porous
screen 40 portion of the mold 36. The mounting plate portion 42 of
the mold 36 is mounted to the periphery 44 of the cylinder 15,
thereby enabling each of the molds 36 to rotate with the rotating
cylinder 15.
[0042] After the mold 36 is rotated under the partially open bottom
portion 34 of the chamber 30, the mold 36 is further rotated by the
rotating cylinder 15, and as described in further detail below, the
fibrous article 12 is then transferred to the calendering station
16.
[0043] After formation in the mold 36, the formed fibrous article
12 preferably has a basis weight in the range of between about 200
gsm (g/m.sup.2) to about 400 gsm, a thickness in the range of about
5 mm to about 20 mm, and a density in the range of about 0.01 g/cc
to about 0.03 g/cc.
[0044] As shown in FIGS. 1 and 5-9 the calendering station 16
generally includes a vacuum roll 42 and an opposed calender roll
44. As best seen in FIG. 6, the vacuum roll 42 is formed from a
rotatable cylinder 46 that is rotatable about a fixed axis 48. The
calender roll 44 is rotateable about a fixed axis 49. Any
conventional means to rotate the cylinder 46, and calender roll 44,
well known to those of skill in the art, may be used to rotate
cylinder 46 and calender roll 44. The cylinder 46 rotates in a
clockwise manner during operation of the apparatus 10, and the
calender roll 44 rotates in a counterclockwise manner, as show in
FIG. 1. As best seen in FIGS. 6, 8 and 9, the cylinder 46 includes
a plurality of holes 50 that extend from the outer surface 52 of
the cylinder 46 to the inner surface 54 of the cylinder 46.
[0045] As shown in detail in FIG. 7, the surface 47 of the calender
roll 44 includes a recess 53. The recess 53 may take any number of
different shapes including generally oval, elliptical, circular or
the like. In one preferred embodiment of the invention, as shown in
FIG. 7, the recess generally has an oval shape. Preferably, the
recess 53 extends over a surface area in range of about 500
mm.sup.2 to about 5000 mm.sup.2. The recess 53 preferably has a
depth in the range of about 2 mm to about 25 mm as measured from
the surface 47 of the roll 44 located outside the recess 53. The
recess 53 is preferably arranged such that it is longer in the
machine direction (md) than in the transverse direction (td).
Preferably, the recess 53 has a maximum length, as measured in the
machine direction, in the range of about 20 mm to about 120 mm and
a maximum width, as measured in the transverse direction, in the
range of about 5 mm to about 60 mm.
[0046] As shown in FIGS. 5, 6 and 8, the vacuum roll 42 further
includes a vacuum chamber 56 arranged within the interior of the
cylinder 46. The vacuum chamber 56 is arranged in a fixed location
relative to the rotating cylinder 46 and is operably coupled to a
vacuum source 57 (FIG. 1). The vacuum chamber 56 is arranged in
flow communication with the plurality of holes 50 that extend
through the cylinder 46 and thereby draws air through said holes
50.
[0047] As shown in FIG. 5, the vacuum chamber 56 is arranged such
that its leading edge 58 is substantially aligned with a trailing
edge 60 of the vacuum chamber 38 located within cylinder 15 of the
forming drum 14. This arrangement of the vacuum chamber 56 relative
to location of the vacuum chamber 38 effectuates a transfer of the
formed fibrous article 12 from within the mold 36 on the forming
drum 14 to the vacuum roll 42.
[0048] Once the formed fibrous article 12 has been transferred to
the cylinder 46 of the vacuum roll 42 the cylinder 46 rotates the
fibrous 12 article until the article 12 passes through the nip 62
formed between the vacuum roll 42 and the calender roll 44. The nip
62 preferably uniformly compresses the fibrous article 12 outside
of the area defined by recess 53. The compression of the fibrous
article 12 results in a reduction in thickness of the article 12
and a corresponding increase in density in that portion of the
fibrous article 12 located outside of the area of the recess 53. In
a preferred embodiment of the invention the nip 62 has a distance
"d" (i.e. the distance between the surfaces of the opposed rolls)
of about 0.9 mm. The distance "d" is indentified by the reference
symbol "d" in FIG. 8.
[0049] As shown in FIG. 10, after passing through the nip 62 the
fibrous article 12 generally includes two areas 59 and 61. The
first area 59, corresponds to that portion of the article 12 that
has been compressed by the rolls 42 and 44 outside of the area of
the recess 53. Area 59 preferably extends over a surface area of
between about 7000 mm.sup.2 and 14000 mm.sup.2, has a thickness in
the range of about 4 mm to about 12 mm, and a density in the range
of about 0.02 g/cc to about 0.1 g/cc. Area 61 of the article 12 is
that portion of the article 12 corresponding in location to the
recess 53. Area 61 preferably extends over a surface area of
between about 1000 mm.sup.2 and 7000 mm.sup.2, has a thickness in
the range of about 10 mm to about 20 mm, and a density in the range
of about 0.01 g/cc to about 0.04 g/cc.
[0050] It is noted that the fibrous article 12, after passing
through the nip 62, has a three dimensional profile. Specifically,
area 59 of the fibrous article defines a substantially planar
portion of the fibrous article 12 and area 61 extends upwardly from
the substantially planar portion thereby defining an upwardly
extending hump or raised portion. In one preferred embodiment of
the invention, as shown in FIG. 10, area 61 is symmetrically
arranged with respect to longitudinally extending central axis 13
of the fibrous article and the transversely extending central axis
19 of the fibrous article 12
[0051] It is noted that the fibrous article 12 has a three
dimensional profile yet has a constant basis weight throughout its
entire structure. Specifically, planar portion 59 and the raised
portion 61 are both formed from a common material composition
having a constant basis weight, yet differ in thickness and
density. It is also noted that the entire fibrous article 12 is
formed from a single material layer.
[0052] After the article 12 passes through the nip 62 the article
12 is further rotated in a clockwise direction by the cylinder 46
of the vacuum roll 43, and as will be described in further detail
below, transferred to the pin calendering station 18.
[0053] As shown in FIGS. 1 and 11-18 the pin calendering station 18
generally includes a vacuum roll 64 and an opposed pin calender
roll 65. As best seen in FIG. 12, the vacuum roll 64 is formed from
a rotatable cylinder 66 that is rotatable about a fixed axis 68.
Any conventional means to rotate the cylinder 66, well known to
those of skill in the art, may be used to rotate the cylinder 66.
The cylinder 66 rotates in a counterclockwise direction during
operation of the apparatus 10. As shown in FIG. 12, the cylinder 66
includes a plurality of holes 70 that extend from the outer surface
72 of the cylinder 66 to the inner surface 74 of the cylinder 66.
In a preferred embodiment of the invention each of the plurality of
holes 70 has a diameter of about 1.5 mm and is spaced from an
adjacent hole by a distance of about 4 mm (center to center).
[0054] As shown in FIGS. 12 and 13 the pin calender roll 65 is
structured and arranged to rotate about a fixed axis 67. Any
conventional means to rotate the pin calender roll, well known to
those of skill in the art, may be used to rotate the roll 65. As
shown in FIGS. 13 and 14 the pin calender roll 65 has a roll
surface 80 including a first area 69 having plurality of individual
pins 78 that extend outwardly from a surface 80 of the roll 65. As
shown in FIG. 13, the first area 69 extends down a central portion
of the roll surface 80. In a preferred embodiment of the invention,
the first area 69 is structured and arranged to emboss a central
region of the fibrous article 12. Alternatively, the first area 69
may be arranged to emboss substantially the entire fibrous article
12.
[0055] As best seen in FIG. 14, the surface 80 of the roll 65 is
further provided with a first recess 77 and a second recess 79.
Each of the first recess 77 and second recess 79 are structured and
arranged to correspond in location to area 61 of the fibrous
article 12 when the article 12 passes through the nip 92 defined
between the vacuum roll 64 and the pin calender roll 65. Preferably
each recess 77 and 79 extends over a surface area of between about
260 mm.sup.2 and 1100 mm.sup.2 and has a depth of between about 2
mm and 25 mm.
[0056] As shown in FIG. 14, in a preferred embodiment of the
invention, each recess 77 and 79 is generally arcuate in shape and
generally extends in a machine direction. Each recess 77 and 79 is
preferably positioned on the roll 65 so that it is symmetrically
arranged with respect to the other recess about the longitudinally
extending central axis 13 of the fibrous article and the
transversely extending central axis 19 of the fibrous article 12,
as the article 12 passes through the through the nip 92 defined
between the vacuum roll 64 and the pin calender roll 65.
[0057] Recess 77 is separated from recess 79 by a land area 81 that
includes a plurality of pins 78. Preferably the land area 81 has a
surface area of between about 250 mm.sup.2 and 1000 mm.sup.2. The
land area 81 is connected to the first area 67 by a first smooth
roll surface segment 83 and second smooth roll surface segment 85,
each of the segments 83 and 85 being preferably free of pins
78.
[0058] In preferred embodiments of the invention each of the pins
78 are spaced from an adjacent pin by a distance of about 4 mm
(center to center), have height of about 1.5 mm and have an
effective contact area of from about 0.8 mm.sup.2 to about 1.2
mm.sup.2.
[0059] As shown in FIGS. 17 and 18, each of the pins 78 are
arranged such that they do not overlap with any of the plurality of
holes 70 in the cylinder 66 of the vacuum roll 64. This arrangement
of the pins 78 relative to the holes 70 insures that no pulp is
forced into any of the plurality of holes 70, thereby improving the
efficiency of pulp use and the efficiency of the process as a
whole.
[0060] As shown in FIGS. 11-12 and 17-18, the vacuum roll 64
further includes a vacuum chamber 86 arranged within the interior
of the cylinder 66. The vacuum chamber 86 is arranged in a fixed
location relative to the rotating cylinder 66 and is operably
coupled to the vacuum source 57 (FIG. 1). The vacuum chamber 86 is
arranged in flow communication with the plurality of holes 70 that
extend through the cylinder 66 and thereby draws air through said
holes 70.
[0061] As shown in FIG. 11, the vacuum chamber 86 is arranged such
that its leading edge 88 is substantially aligned with a trailing
edge 90 of the vacuum chamber 56 located within the cylinder 46 of
the vacuum roll 42. This arrangement of the vacuum chamber 86
relative to the location of the vacuum chamber 56 effectuates a
transfer of the formed fibrous article 12 from the vacuum roll 42
to the vacuum roll 64.
[0062] Once the formed fibrous article 12 has been transferred to
the cylinder 66 of the vacuum roll 64, the cylinder 66 rotates the
formed fibrous article 12 until the article 12 passes through the
nip 92 formed by the vacuum roll 64 and the pin calender roll
65.
[0063] In a preferred embodiment of the invention the nip 92 has a
distance (i.e. the distance between the surfaces of the opposed
rolls) of about 0.8 mm. Also in a preferred embodiment of the
invention the pin calender roll 65 is heated to a temperature of
between about 176.degree. F. to about 212.degree. F. by means of
any suitable conventional heating means. It has been found that
heating the pin calender roll 65 in this manner helps prevent the
formed fibrous article 12 from adhering to the surface of the pin
calender roll 65.
[0064] After the article 12 passes through the nip 92 the article
12 is further rotated in a counter clockwise direction by the
cylinder 66 of the vacuum roll 64 as shown and, as will be
described in further detail below, transferred to the transfer
wheel 20.
[0065] As shown in FIG. 19 the transfer wheel 20 comprises a vacuum
roll 94 that is formed from a rotatable cylinder 96 that is
rotatable about a fixed axis 98. Any conventional means to rotate
the cylinder 96, well known to those of skill in the art, may be
used to rotate the cylinder 96. The cylinder 96 rotates in a
counterclockwise manner during operation of the apparatus 10, as
show in FIG. 1. As shown in FIG. 20, the cylinder 96 includes a
plurality of holes 100 that extend from the outer surface 102 of
the cylinder 96 to the inner surface 104 of the cylinder 96.
[0066] As shown in FIGS. 19 and 20, the vacuum roll 94 further
includes a vacuum chamber 106 arranged within the interior of the
cylinder 96. The vacuum chamber 106 is arranged in a fixed location
relative to the rotating cylinder 96 and is operably coupled to the
vacuum source 57 (FIG. 1). The vacuum chamber 106 is arranged in
flow communication with the plurality of holes 100 that extend
through the cylinder 96 and thereby draw air through said holes
100.
[0067] The transfer wheel 20 further includes a porous conveyor
belt 97 that extends around the cylinder 96 and travels with the
cylinder 96, i.e. in a clockwise direction shown in FIG. 20.
[0068] As shown in FIG. 19, the vacuum chamber 106 is arranged such
that its leading edge 108 is substantially aligned with a trailing
edge 110 of the vacuum chamber 86 located within the cylinder 66 of
the vacuum roll 64. This arrangement of the vacuum chamber 106
relative to the location of the vacuum chamber 86 effectuates a
transfer of the formed fibrous article 12 from the vacuum roll 64
to the vacuum roll 94. Specifically, formed fibrous article 12 is
transferred to the conveyor belt 97 and held in place by the vacuum
chamber 106 that functions to draw air through the porous conveyer
belt 97 via the holes 100 in the cylinder 96.
[0069] Once the fibrous article 12 is rotated past vacuum chamber
106, the porous conveyer belt 97 functions to further convey the
formed fibrous article 12 in a machine direction. The formed
fibrous article 12 may be conveyed in a machine direction for
incorporation into a final product structure such as a sanitary
napkin, panty liner, incontinence article, diaper or the like.
[0070] Referring to FIGS. 21 and 22, the completed fibrous article
12 generally includes an area 101 that has not been pin embossed, a
first arcuate raised area 103, a second arcuate raised area 105, a
pin embossed region 107 located between the raised area 103 and
raised area 105, and a centrally extending pin embossed area 109
extending along the longitudinally extending central axis 13 of the
article 12. Each of the pin embossed regions 107 and 109 include a
plurality of depressions 111 corresponding in location to the pins
78. Areas 101 and 109 cooperate to define a substantially planar
portion of the fibrous article 12 and raised areas 103 and 105
extend upwardly relative to the planar portion of the fibrous
article 12.
[0071] After passing through the nip 92 area 101 preferably has a
thickness in the range of about 0.8 mm to about 3.5 mm, a density
in the range of about 0.06 g/cc to about 0.5 g/cc, and extends over
a surface area of from about 6400 mm.sup.2 and 9400 mm.sup.2.
[0072] After passing through the nip 92 each of area 103 and 105
preferably has a thickness in the range of about 2 mm to about 10
mm and a density in the range of about 0.01 g/cc to about 0.1 g/cc.
Each area 103 and 105 preferably extends over a surface area of
from about 260 mm.sup.2 and 1100 mm.sup.2.
[0073] After passing through the nip 92 area 107 preferably has a
thickness in the range of about 0.2 mm to about 1 mm, a density in
the range of about 0.1 g/cc to about 0.9 g/cc in those areas 111
embossed by the pins 78 and a thickness in the range of about 0.8
mm to about 3.5 mm and a density in the range of about 0.06 g/cc to
about 0.5 g/cc in those areas outside of areas 111. Area 107
preferably extends over a surface area of from about 250 mm.sup.2
and 1000 mm.sup.2.
[0074] After passing through the nip 92 area 109 preferably has a
thickness in the range of about 0.2 mm to about 1.0 mm and a
density in the range of about 0.1 g/cc to about 0.9 g/cc in those
areas 111 embossed by the pins 78 and a thickness in the range of
about 0.8 mm to about 3.5 mm and a density in the range of about
0.06 g/cc to about 0.5 g/cc in those areas outside of areas 111.
Area 109 preferably extends over a surface area of from about 2400
mm.sup.2 and 7600 mm.sup.2.
[0075] It is noted that although the different areas of the fibrous
article 12 differ in density and thickness the fibrous article 12
has a uniform basis weight throughout its entire structure. It is
further noted that although fibrous article 12 according to the
present invention possesses at least one raised area, i.e. the
article 12 possesses a three dimensional profile, the article 12
has a uniform basis weight. Preferred embodiments of the present
invention also present the above characteristics while being formed
from a uniform material composition. In addition, in preferred
embodiments of the present invention, the fibrous article 12 is
formed from a single material layer.
[0076] It is noted that the formed fibrous article 12 is formed and
pin-calendered without the use of any "carrier layer". In addition,
is noted that the fibrous article is transferred from the forming
drum 14 to the calendering station 16 then to the pin calendering
station 18 without the use of any "carrier layer". "Carrier layer"
as used herein means any material layer used to support the fibrous
article, such as a conveyer belt or an adjacent material layer such
a rolled nonwoven layer or the like.
[0077] In connection with the various vacuum chambers disclosed
herein any suitable vacuum source may be employed. In a preferred
embodiment of the invention the vacuum source is an air blower
having an air flow of about 2,200 cubic meters per hour.
[0078] Reference is made to FIGS. 23-24 which depict a disposable
absorbent article 200 in accordance with the present invention.
Although disposable absorbent articles according to the present
invention will be described herein with reference to a sanitary
napkin 200, other disposable absorbent articles such as panty
liners, adult incontinence articles, and diapers are considered
within the scope of the present invention. As shown in FIG. 24, the
sanitary napkin 200 includes a liquid permeable cover layer 210, an
optional transfer layer 212, an absorbent core 214 and a liquid
impermeable barrier layer 216. The absorbent core 214 layer is
formed from a formed fibrous article 12 of the type described
above.
[0079] As shown in FIG. 23, the absorbent article 200 includes a
raised area 213 that extends upwardly from the remaining body
facing planar portion 215 of the napkin 200. Specifically the
raised area 213 extends upwardly from a top surface 217 of the
planar portion 215. Preferably, the raised area 213 extends
upwardly a distance of about 2 mm to about 10 mm as measured from
the top surface 217 of the planar portion 215 and extends over a
surface area of between about 1000 mm.sup.2 and 7000 mm.sup.2.
Preferably, the planar portion 215 extends over an area of between
about 7000 mm.sup.2 and 14000 mm.sup.2.
Main Body--Cover Layer
[0080] The cover layer 210 may be a relatively low density, bulky,
high-loft non-woven web material. The cover layer 210 may be
composed of only one type of fiber, such as polyester or
polypropylene or it may include a mixture of more than one fiber.
The cover may be composed of bi-component or conjugate fibers
having a low melting point component and a high melting point
component. The fibers may be selected from a variety of natural and
synthetic materials such as nylon, polyester, rayon (in combination
with other fibers), cotton, acrylic fiber and the like and
combinations thereof. Preferably, the cover layer 210 has a basis
weight in the range of about 10 gsm to about 75 gsm.
[0081] Bi-component fibers may be made up of a polyester layer and
a polyethylene sheath. The use of appropriate bi-component
materials results in a fusible non-woven fabric. Examples of such
fusible fabrics are described in U.S. Pat. No. 4,555,430 issued
Nov. 26, 1985 to Chicopee. Using a fusible fabric increases the
ease with which the cover layer may be mounted to the absorbent
layer(s) of the article and/or to the barrier layer 216.
[0082] The cover layer 210 preferably has a relatively high degree
of wettability, although the individual fibers comprising the cover
may not be particularly hydrophilic. The cover material should also
contain a great number of relatively large pores. This is because
the cover layer 210 is intended to take-up body fluid rapidly and
transports it away from the body and the point of deposition.
Therefore, the cover layer contributes little to the time taken for
the napkin 200 to absorb a given quantity of liquid (penetration
time).
[0083] Advantageously, the fibers that make up the cover layer 210
should not lose there physical properties when they are wetted, in
other words they should not collapse or lose their resiliency when
subjected to water or body fluid. The cover layer 210 may be
treated to allow fluid to pass through it readily. The cover layer
210 also functions to transfer the fluid quickly to the underlying
layers of the absorbent article. Thus, the cover layer 210 is
advantageously wettable, hydrophilic and porous. When composed of
synthetic hydrophobic fibers such as polyester or bi-component
fibers, the cover layer 210 may be treated with a surfactant to
impart the desired degree of wettability.
[0084] In one preferred embodiment of the invention the cover layer
210 is made from a 27 gsm hot through air (HTA) bonded nonwoven
material constructed from 100% bico fibers (PE/PET), commercially
available from Shalag Industries A.C.S. Ltd., Kibbutz Shamir, Upper
Galilee, Israel, under the commercial code STA4ETW27.
[0085] Alternatively, the cover layer 210 can also be made of a
polymer film having large pores. Because of such high porosity, the
film accomplishes the function of quickly transferring body fluid
to the underlying layers of the absorbent article. A suitable cover
material of this type is commercially found on the Stayfree Dry Max
Ultrathin product distributed by McNeil-PPC, Inc.
[0086] The cover layer 210 may be embossed to the underlying
absorbent layers in order to aid in promoting hydrophilicity by
fusing the cover to the adjacent underlying layer. Such fusion may
be effected locally, at a plurality of sites or over the entire
contact surface of cover layer 210. Alternatively, the cover layer
210 may be attached to the other layers of the article by other
means such as by adhesion.
Main Body--Transfer Layer
[0087] Adjacent to the cover layer 210 on its inner side and bonded
to the cover layer 210 is the optional transfer layer 212. The
transfer layer 212 provides means for receiving body fluid from the
cover layer 210 and holding it until the underlying absorbent core
214 has an opportunity to absorb the fluid, and therefore acts as a
fluid transfer or acquisition layer. The transfer layer 212 is,
preferably, more dense than and has a larger proportion of smaller
pores than the cover layer 210. These attributes allow the transfer
layer 212 to contain body fluid and hold it away from the outer
side of the cover layer 210, thereby preventing the fluid from
rewetting the cover layer 210 and its surface. However, the
transfer layer is, preferably, not so dense as to prevent the
passage of the fluid through the layer 212 into the underlying
absorbent core 214.
[0088] The transfer layer 212 may be composed of fibrous materials,
such as wood pulp, polyester, rayon, flexible foam, or the like, or
combinations thereof. The transfer layer 212 may also comprise
thermoplastic fibers for the purpose of stabilizing the layer and
maintaining its structural integrity. The transfer layer 212 may be
treated with surfactant on one or both sides in order to increase
its wettability, although generally the transfer layer 212 is
relatively hydrophilic and may not require treatment. The transfer
layer 212 is preferably bonded or adhered on both sides to the
adjacent layers, i.e. the cover layer 210 and the underlying
absorbent core 214.
[0089] Examples of suitable materials for the transfer layer 212
are through air bonded pulp sold by Buckeye Technologies of
Memphis, Tenn., under the designation VIZORB 3008, which has a
basis weight of 110 gsm, VIZORB 3042, which has a basis weight of
100 gsm, and VIZORB 3010, which has a basis weight of 90 gsm.
Main Body--Absorbent Core
[0090] Referring to FIG. 18, and as discussed above, the absorbent
article 200 according to the present invention includes an
absorbent core 214. The absorbent core 214 consists of a formed
fibrous article 12 of the type described herein above.
[0091] In one preferred embodiment of the invention, the absorbent
core 214 is a blend or mixture of cellulosic fibers and
superabsorbent disposed therein. Cellulosic fibers that can be used
in the absorbent core 214 are well known in the art and include
wood pulp, cotton, flax and peat moss. Wood pulp is preferred.
[0092] The absorbent core 214 can contain any superabsorbent
polymer (SAP), which are well known in the art. For the purposes of
the present invention, the term "superabsorbent polymer" (or "SAP")
refers to materials, which are capable of absorbing and retaining
at least about 10 times their weight in body fluids under a 0.5 psi
pressure. The superabsorbent polymer particles of the invention may
be inorganic or organic crosslinked hydrophilic polymers, such as
polyvinyl alcohols, polyethylene oxides, crosslinked starches, guar
gum, xanthan gum, and the like. The particles may be in the form of
a powder, grains, granules, or fibers. Preferred superabsorbent
polymer particles for use in the present invention are crosslinked
polyacrylates, such as the product offered by Sumitomo Seika
Chemicals Co., Ltd. of Osaka, Japan, under the designation of SA70N
and products offered by Stockhausen Inc.
[0093] The absorbent core 214 preferably has a total basis weight
in the range of about 200 gsm to about 400 gsm. In preferred
embodiments of the present invention the absorbent core 214
includes about 50%-100% pulp by weight and about 0% to about 50%
superabsorbent by weight.
[0094] As described above in the description of the method of
making the fibrous article 12 set forth above, and in reference to
FIGS. 21 and 22, the absorbent core 214 generally includes an area
101 that has not been pin embossed, a first arcuate raised area
103, a second arcuate raised area 105, a pin embossed region 107
located between the raised area 103 and raised area 105, and a
centrally extending pin embossed area 109. Referring to FIG. 24, it
is noted that the region 107 located between the raised areas 103
and 105 is recessed related to the raised areas. That is, raised
areas 103 and 105 have a greater thickness than region 107.
[0095] As shown in FIG. 24, the first arcuate raised area 103 and
the second arcuate raised area 105 of the absorbent core 214
correspond in location, and help define, the raised area 213 of the
napkin 200. However, it is noted that the final shape of the raised
area 213 of the napkin 200 is provided by a conventional embossing
step (not shown in the figures) and thus the shape of the raised
area 213 is not dictated solely by the shape of the first arcuate
raised area 103 and the second arcuate raised area 105. The raised
area 213 of the napkin 200 may be formed to have any number of
different shapes. For example, two alternate embodiments of the
napkin 200a and 200b are depicted in FIGS. 25 and 26. As shown,
napkins 200a and 200b include raised areas 213 having different
shapes than the napkin 200 shown in FIGS. 23 and 24. Other shapes
are also possible. In addition, although the napkin 200 is depicted
as having only a single raised area 213 is possible that the napkin
could be provided with a plurality of such raised areas 213.
[0096] All of the articles shown in FIGS. 23-26 use absorbent cores
having raised areas 103 and 105 as shown in FIG. 21, and the final
shape of the raised area 213 has been modified merely by using a
correspondingly shaped conventional embossing roll to emboss the
napkin 200 after the various layers of the napkin 200 have been
adhered to one another.
[0097] Referring to FIG. 24, it is noted that the cover layer
extends over the first arcuate raised area 103, the second arcuate
raised area 105, as well as the region 107 located between the
raised area 103 and raised area 105. In this manner, the cover
layer 210 generally includes a first portion 221 which is located
in body facing planar portion 215 of the napkin 200 and is arranged
in abutting surface to surface contact with the transfer layer 212
(or the absorbent core 214 if the transfer layer 212 is omitted), a
pair of second regions 223 that are arranged in corresponding
location to the arcuate raised areas 103 and 105 of the absorbent
core 214, and a third region 225 that is located between the
arcuate raised areas 103 and 105 and is arranged in spaced
relationship to the absorbent core 214.
[0098] In one specific example of the invention, the absorbent core
214 consists of a 305 gsm fluff pulp and superabsorbent mixture,
the mixture including about 89% fluff pulp by weight, commercially
available as Golden Isles Fluff Pulp 420#HD 7% Moisture, from GP
Cellulose, Brunswick, Ga., USA, and 11% superabsorbent polymer by
weight, commercially available as Aqua Keep SA70N from Sumitomo
Seika Chemicals Co., Ltd., Osaka, Japan.
Main Body--Barrier Layer
[0099] Underlying the absorbent core 214 is a barrier layer 216
comprising liquid-impervious film material so as to prevent liquid
that is entrapped in the absorbent core 214 from egressing the
sanitary napkin 200 and staining the wearer's undergarment. The
barrier layer 216 is preferably made of polymeric film, although it
may be made of liquid impervious, air-permeable material such as
repellent-treated non-woven or micropore films or foams.
[0100] The barrier layer may be breathable, i.e., permits vapor to
transpire. Known materials for this purpose include nonwoven
materials and microporous films in which microporosity is created
by, inter alia, stretching an oriented film. Single or multiple
layers of permeable films, fabrics, melt-blown materials, and
combinations thereof that provide a tortuous path, and/or whose
surface characteristics provide a liquid surface repellent to the
penetration of liquids may also be used to provide a breathable
backsheet. The cover layer 210 and the barrier layer 216 are joined
along their marginal portions so as to form an enclosure or flange
seal that maintains the absorbent core 214 captive. The joint may
be made by means of adhesives, heat-bonding, ultrasonic bonding,
radio frequency sealing, mechanical crimping, and the like and
combinations thereof.
[0101] In one specific example of the invention, the barrier layer
consists of a liquid impermeable 24 gsm polyethylene film
commercially available from Clopay do Brasil, Sau Paulo, SP,
Brazil.
[0102] Positioning adhesive may be applied to a garment facing side
of the barrier layer 216 for securing the napkin 200 to the garment
during use. The positioning adhesive may be covered with removable
release paper so that the positioning adhesive is covered by the
removable release paper prior to use.
[0103] Absorbent articles of this invention may or may not include
wings, flaps or tabs for securing the absorbent article to an
undergarment. Wings, also called, among other things, flaps or
tabs, and their use in sanitary protection articles is described in
U.S. Pat. No. 4,687,478 to Van Tilburg; U.S. Pat. No. 4,589,876
also to Van Tilburg, U.S. Pat. No. 4,900,320 to McCoy, and U.S.
Pat. No. 4,608,047 to Mattingly.
[0104] The sanitary napkin 200 of the present invention may be
applied to the crotch by placing the garment-facing surface against
the inside surface of the crotch of the garment. Various methods of
attaching absorbent articles may be used. For example, chemical
means, e.g., adhesive, and mechanical attachment means, e.g.,
clips, laces, ties, and interlocking devices, e.g., snaps, buttons,
VELCRO (Velcro USA, Inc., Manchester, N.H.), zipper, and the like
are examples of the various options available to the artisan.
[0105] Adhesive may include pressure sensitive adhesive that is
applied as strips, swirls, or waves, and the like. As used herein,
the term pressure-sensitive adhesive refers to any releasable
adhesive or releasable tenacious means. Suitable adhesive
compositions, include, for example, water-based pressure-sensitive
adhesives such as acrylate adhesives. Alternatively, the adhesive
composition may include adhesives based on the following: emulsion
or solvent-borne adhesives of natural or synthetic polyisoprene,
styrenebutadiene, or polyacrylate, vinyl acetate copolymer or
combinations thereof; hot melt adhesives based on suitable block
copoylmers--suitable block copolymers for use in the invention
include linear or radial co-polymer structures having the formula
(A-B)x wherein block A is a polyvinylarene block, block B is a
poly(monoalkenyl) block, x denotes the number of polymeric arms,
and wherein x is an integer greater than or equal to one. Suitable
block A polyvinylarenes include, but are not limited to
Polystyrene, Polyalpha-methylstyrene, Polyvinyltoluene, and
combinations thereof. Suitable Block B poly(monoalkenyl) blocks
include, but are not limited to conjugated diene elastomers such as
for example polybutadiene or polyisoprene or hydrogenated
elastomers such as ethylene butylene or ethylene propylene or
polyisobutylene, or combinations thereof. Commercial examples of
these types of block copolymers include Kraton.TM. elastomers from
Shell Chemical Company, Vector.TM. elastomers from Dexco,
Solprene.TM. from Enichem Elastomers and Stereon.TM. from Firestone
Tire & Rubber Co.; hot melt adhesive based on olefin polymers
and copolymers where in the olefin polymer is a terpolymer of
ethylene and a co-monomers, such as vinyl acetate, acrylic acid,
methacrylic acid, ethyl acrylate, methyl acrylate, n-butyl acrylate
vinyl silane or maleic anhydride. Commercial examples of these
types of polymers include Ateva (polymers from AT plastics), Nucrel
(polymers from DuPont), Escor (from Exxon Chemical).
[0106] Any or all of the cover layer 210, transfer layer 212,
absorbent core 214, barrier layer 216, and adhesive layers may be
colored. Such coloring includes, but is not limited to, white,
black, red, yellow, blue, orange, green, violet, and mixtures
thereof. Color may be imparted according to the present invention
through dying, pigmentation, and printing. Colorants used according
the present invention include dyes and inorganic and organic
pigments. The dyes include, but are not limited to, anthraquinone
dyes (Solvent Red 111, Disperse Violet 1, Solvent Blue 56, and
Solvent Green 3), Xanthene dyes (Solvent Green 4, Acid Red 52,
Basic Red 1, and Solvent Orange 63), azine dyes (Jet black), and
the like. Inorganic pigments include, but are not limited to,
titanium dioxide (white), carbon black (black), iron oxides (red,
yellow, and brown), chromium oxide (green), ferric ammonium
ferrocyanide (blue), and the like.
[0107] Organic pigments include, but are not limited to diarylide
yellow AAOA (Pigment Yellow 12), diarylide yellow AAOT (Pigment
Yellow 14), phthalocyanine blue (Pigment Blue 15), lithol red
(Pigment Red 49:1), Red Lake C (Pigment Red), and the like.
[0108] The sanitary napkin 200 may include other known materials,
layers, and additives, such as, foam, net-like materials, perfumes,
medicaments or pharmaceutical agents, moisturizers, odor control
agents, and the like. The sanitary napkin 200 can optionally be
embossed with decorative designs.
[0109] The sanitary napkin 200 may be packaged as unwrapped
absorbent articles within a carton, box or bag. The consumer
withdraws the ready-to-use article as needed. The sanitary napkin
200 may also be individually packaged (each absorbent article
encased within an overwrap).
[0110] Also contemplated by the present invention are asymmetrical
and symmetrical absorbent articles having parallel longitudinal
edges, dog bone- or peanut-shaped, as well as articles having a
tapered construction for use with thong-style undergarments.
[0111] From the foregoing description, one skilled in the art can
ascertain the essential characteristics of this invention, and
without departing from the spirit and scope thereof, can make
various changes and modifications. Embodiments set forth by way of
illustration are not intended as limitations on the variations
possible in practicing the present invention.
EXAMPLES
[0112] Specific inventive examples of the present invention, and
comparative examples, are described below.
Inventive Example #1
[0113] An example of a sanitary napkin according to the invention
was constructed as follows. The body facing cover layer was
constructed from a 27 gsm hot through air (HTA) bonded nonwoven
material constructed from 100% bico fibers (PE/PET), commercially
available from Shalag Industries A.C.S. Ltd., Kibbutz Shamir, Upper
Galilee, Israel, under the commercial code STA4ETW27.
[0114] A 305 gsm formed fibrous absorbent core was arranged below
the cover layer and was formed by the process described herein
above with reference to FIGS. 1-21.
The absorbent core had a composition of 89% by weight of pulp and
11% by weight of superabsorbent polymer. The pulp was Golden Isles
Fluff Pulp 420#HD 7% Moisture, commercially available from GP
Cellulose, Brunswick, Ga., USA. The superabsorbent polymer was Aqua
Keep SA70N commercially available from Sumitomo Seika Chemicals
Co., Ltd., Osaka, Japan.
[0115] As described above with reference to FIGS. 21-22, the
absorbent core (i.e. the formed fibrous article 12) was formed to
include an area 101 that was not been pin embossed, a first arcuate
raised area 103, a second arcuate raised area 105, a pin embossed
region 107 located between the raised area 103 and raised area 105,
and a centrally extending pin embossed area 109 extending along the
longitudinally extending central axis of the article 12, as shown
in FIG. 21.
[0116] Area 101 had a thickness in the range of about 2 mm, a
density of about 0.1 g/cc, and extended over a surface area of 6500
mm.sup.2.
[0117] Area 103 and 105 each had a thickness of 5 mm and a density
of about 0.05 g/cc. Each area 103 and 105 extended over a surface
area of 557 mm.sup.2.
[0118] Area 107 had a thickness of 0.2 mm and a density of 0.5 g/cc
in those areas 111 embossed by the pins 78 and a density of 0.3
g/cc and a thickness of 1 mm in those areas outside of areas 111.
Area 107 extended over a surface area of 504 mm.sup.2.
[0119] Area 109 had a thickness of 0.2 mm and a density of 0.5 g/cc
in those areas 111 embossed by the pins 78 and a thickness of 1 mm
and a density of 0.3 g/cc in those areas outside of areas 111. Area
109 extended over a surface area of 4300 mm.sup.2.
[0120] A barrier layer was arranged below the core and was formed
from a 24 gsm polyethylene film commercially available from Clopay
do Brasil, Sao Paulo, SP, Brazil.
[0121] Each of the layers of the sanitary napkin were adhered to
one another using a conventional hot melt adhesive. After each of
the layers were adhered to one another the sanitary napkin was
passed through a conventional embossing process to form a raised
area of the type shown in FIG. 23. Thus, the sanitary napkin
included a planar portion 215 and a raised area 213 extending
upwardly form the planar portion 215 as depicted in FIG. 23. The
planar portion 215 extended over an area of 13000 mm.sup.2 and the
raised area 213 extended over an area of 2000 mm.sup.2. The
sanitary napkin had a thickness of 2.2 mm in the planar portion 215
and a thickness of 4.7 mm in the raised area 213.
Inventive Example #2
[0122] An example of a sanitary napkin according to the invention
was constructed as follows. The body facing cover layer was
constructed from a 27 gsm hot through air (HTA) bonded nonwoven
material constructed from 100% bico fibers (PE/PET), commercially
available from Shalag Industries A.C.S. Ltd., Kibbutz Shamir, Upper
Galilee, Israel, under the commercial code STA4ETW27.
[0123] A 305 gsm formed fibrous absorbent core was arranged below
the cover layer and was formed by the process described herein
above with reference to FIGS. 1-21.
The absorbent core had a composition of 89% by weight of pulp and
11% by weight of superabsorbent polymer. The pulp was Golden Isles
Fluff Pulp 420#HD 7% Moisture, commercially available from GP
Cellulose, Brunswick, Ga., USA. The superabsorbent polymer was Aqua
Keep SA70N commercially available from Sumitomo Seika Chemicals
Co., Ltd., Osaka, Japan.
[0124] As described above with reference to FIGS. 21-22, the
absorbent core (i.e. the fibrous article 12) was formed to include
an area 101 that was not been pin embossed, a first arcuate raised
area 103, a second arcuate raised area 105, a pin embossed region
107 located between the raised area 103 and raised area 105, and a
centrally extending pin embossed area 109 extending along the
longitudinally extending central axis 13 of the article 12, as
shown in FIG. 21.
[0125] Area 101 had a thickness in the range of about 3 mm, a
density of about 0.09 g/cc, and extended over a surface area of
6500 mm.sup.2.
[0126] Area 103 and 105 each had a thickness of 6 mm and a density
of about 0.04 g/cc. Each area 103 and 105 extended over a surface
area of 557 mm.sup.2.
[0127] Area 107 had a thickness of 0.2 mm and a density of 0.5 g/cc
in those areas 111 embossed by the pins 78 and a density of 0.3
g/cc and a thickness of 1 mm in those areas outside of areas 111.
Area 107 extended over a surface area of 504 mm.sup.2.
[0128] Area 109 had a thickness of 0.2 mm and a density of 0.5 g/cc
in those areas 111 embossed by the pins 78 and a thickness of 1 mm
and a density of 0.3 g/cc in those areas outside of areas 111. Area
109 extended over a surface area of 4300 mm.sup.2.
[0129] Each of the layers of the sanitary napkin were adhered to
one another using a conventional hot melt adhesive. After each of
the layers were adhered to one another the sanitary napkin was
passed through a conventional embossing process to form a raised
area of the type shown in FIG. 23. Thus, the sanitary napkin
included a planar portion 215 and a raised area 213 extending
upwardly form the planar portion 215 as depicted in FIG. 23. The
planar portion 215 extended over an area of 13000 mm.sup.2 and the
raised area 213 extended over an area of 2000 mm.sup.2. The
sanitary napkin had a thickness of 3.3 mm in the planar portion 215
and a thickness of 5.8 mm in the raised area 213.
Comparative Example #1
[0130] A comparative example, representative of the prior art, was
construed as follows. The body facing cover layer was constructed
from a 27 gsm hot through air (HTA) bonded nonwoven material
constructed from 100% bico fibers (PE/PET), commercially available
from Shalag Industries A.C.S. Ltd., Kibbutz Shamir, Upper Galilee,
Israel, under the commercial code STA4ETW27.
[0131] A 305 gsm fibrous absorbent core was arranged below the
cover layer.
The absorbent core had a composition of 89% by weight of pulp and
11% by weight of superabsorbent polymer. The pulp was Golden Isles
Fluff Pulp 420#HD 7% Moisture, commercially available from GP
Cellulose, Brunswick, Ga., USA. The superabsorbent polymer was Aqua
Keep SA70N commercially available from Sumitomo Seika Chemicals
Co., Ltd., Osaka, Japan. The absorbent core has a uniform thickness
along its length of 2.2 mm and a uniform density along its length
of 0.1 g/cc.
Comparative Example #2
[0132] A comparative example, representative of the prior art, was
construed as follows. The body facing cover layer was constructed
from a 27 gsm hot through air (HTA) bonded nonwoven material
constructed from 100% bico fibers (PE/PET), commercially available
from Shalag Industries A.C.S. Ltd., Kibbutz Shamir, Upper Galilee,
Israel, under the commercial code STA4ETW27.
[0133] A 305 gsm fibrous absorbent core was arranged below the
cover layer.
The absorbent core had a composition of 89% by weight of pulp and
11% by weight of superabsorbent polymer. The pulp was Golden Isles
Fluff Pulp 420#HD 7% Moisture, commercially available from GP
Cellulose, Brunswick, Ga., USA. The superabsorbent polymer was Aqua
Keep SA70N commercially available from Sumitomo Seika Chemicals
Co., Ltd., Osaka, Japan. The absorbent core has a uniform thickness
along its length of 3.3 mm and a uniform density along its length
of 0.09 g/cc.
Test Procedures
[0134] Absorbent articles according to the present invention
provide superior fluid handling characteristics. A number of test
procedures are described below that highlight the fluid handling
properties of absorbent articles according to the present
invention. Prior to conducting any of the described test procedures
described below the test product samples should be conditioned for
two hours at 21+/-1.degree. C. and 50+/-2% humidity.
Procedure for Measuring Fluid Penetration Time
[0135] Fluid Penetration Time is measured by placing a product
sample to be tested under a Fluid Penetration Test orifice plate.
The orifice plate consists of a 7.6 cm.times.25.4 cm plate of 1.3
cm thick polycarbonate with an elliptical orifice in its center.
The elliptical orifice measures 3.8 cm along its major axis and 1.9
cm along its minor axis. The orifice plate is arranged such that
the center of the orifice is aligned with the intersection of the
longitudinal and transverse axis of the article, i.e. at the center
of the article.
[0136] Test fluid was made of the following mixture to simulate
bodily fluids:
49.5% of 0.9% sodium chloride solution (VWR catalog #VW 3257-7),
49.05% Glycerin (Emery 917), 1% Phenoxyethanol (Clariant
Corporation Phenoxetol.TM.) and 0.45% Sodium Chloride (Baker sodium
chloride crystal # 9624-05).
[0137] A graduated 10 cc syringe containing 7 ml of test fluid is
held over the orifice plate such that the exit of the syringe is
approximately 3 inches above the orifice. The syringe is held
horizontally, parallel to the surface of the test plate. The fluid
is then expelled from the syringe at a rate that allows the fluid
to flow in a stream vertical to the test plate into the orifice and
a stop watch is started when the fluid first touches the sample to
be tested. The stop watch is stopped when a portion of the surface
of the sample first becomes visible above the remaining fluid
within the orifice. The elapsed time on the stop watch is the Fluid
Penetration Time. The average Fluid Penetration Time (FPT) is
calculated from taking the average of readings from three product
samples.
Procedure for Measuring Rewet Potential
[0138] The three product samples used for the Fluid Penetration
Time (FPT) procedure described above are used for the Rewet
Potential test described below.
[0139] The rewet potential is a measure of the ability of a napkin
or other article to hold liquid within its structure when the
napkin contains a relatively large quantity of liquid and is
subjected to external mechanical pressure. The rewet potential is
determined and defined by the following procedure.
[0140] The apparatus for the Rewet Potential test is the same as
that set forth above with regard to the FPT test and further
includes a quantity of 3 inch.times.4 (7.62 cm.times.10.16 cm) inch
rectangles of Whatman #1 filter paper from (Whatman Inc., Clifton,
N.J.) and a weighing machine or balance capable of weighing to an
accuracy of +/-.0.001 g, a quantity of said Whatman paper, a
standard weight of 2.22 kg (4.8 pounds) having dimensions 5.1 cm (2
inches) by 10.2 cm (4.0 inches) by approximately 5.4 cm (2.13
inches) which applies a pressure of 4.14 kPa (0.6 psi) over the 5.1
by 10.2 cm (2 inches by 4 inches) surface.
[0141] For purposes of the test procedure set forth herein, the
same three product samples used for the fluid penetration test
should be used for the rewet potential test. After the test fluid
is applied within the orifice plate in the FPT test described
above, and as soon as the cover layer of the napkin first appears
through the top surface of the fluid, the stop watch is started and
an interval of 5 minutes is measured.
[0142] After 5 minutes have elapsed, the orifice plate is removed
and the napkin is positioned on a hard level surface with the cover
layer facing upwards.
[0143] A fifteen (15) layer stack of the pre-weighed filter paper
is placed on and centered over the wetted area and the standard
2.22 kg weight is placed on top of the filter paper. The filter
paper and the weight are arranged over the absorbent article such
that they are centered over the area to which the fluid was
applied. The filter paper and the weight are arranged such that
their longer dimensions are aligned with the longitudinal direction
of the product. Immediately after placing the paper and weight on
the product, the stopwatch is started and after a 3 minute interval
has elapsed the standard weight and filter paper are quickly
removed. The wet weight of the filter paper is measured and
recorded to the nearest 0.001 grams. The rewet value is then
calculated as the difference in grams between the weight of the wet
15 layers of filter paper and the dry 15 layers of filter paper.
The average Rewet Potential is calculated from taking the average
of readings from three product samples.
Procedure for Measuring the Thickness of a Sanitary Article
[0144] The apparatus required to measure the thickness of the
sanitary napkin is a footed dial (thickness) gauge with stand,
available from Ames, with a 2'' (5.08 cm) diameter foot at a
pressure of 0.07 psig (4.826 hPa) and a readout accurate to 0.001''
(0.0254 mm). A digital type apparatus is preferred. If the sanitary
napkin sample is individually folded and wrapped, the sample is
unwrapped and carefully flattened by hand. The release paper is
removed from the product sample and it is repositioned back gently
across the positioning adhesive lines so as not to compress the
sample, ensuring that the release paper lies flat across the
sample. Flaps (if any) are not considered when taking the thickness
reading.
[0145] The foot of the gauge is raised and the product sample is
placed on the anvil such that the foot of the gauge is
approximately centered on the location of interest on the product
sample. When lowering the foot, care must be taken to prevent the
foot dropping onto the product sample or undue force being applied.
A load of 0.07 psig (4.826 hPa) is applied to the sample and the
read out is allowed to stabilize for approximately 5 seconds. The
thickness reading is then taken. This procedure is repeated for
three product samples and the average thickness is then
calculated.
[0146] The measured Fluid Penetration Time, Rewet Potential and
Product Thickness of the Inventive Examples and Comparative
Examples described above are summarized in the table set forth
below.
TABLE-US-00001 Thickness in Thickness in Raised Area Planar Portion
Fluid Penetra- Rewet (mm) (mm) tion Time (s) (g) Inventive Ex- 4.7
2.2 17 0.98 ample #1 Inventive Ex- 5.8 3.3 11 0.96 ample #2
Comparative NA 2.2 52 0.82 Example #1 Comparative NA 3.3 25 1.43
Example #2
As shown above, disposable absorbent articles according to the
present provide superior fluid handling characteristics.
* * * * *