Note: Descriptions are shown in the official language in which they were submitted.
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MECHANICAL FASTENING SYSTEM HAVING ORTIiOGONALLY ORIENTED
ENGAGEMENT MEMBERS
Field of the Invention
The present invention relates to fastening systems for garments and other
articles.
More particularly, the present invention relates to interlocking, mechanical-
type fastening
systems which can be employed with disposable articles, such as gowns,
diapers,
incontinence garments and the like.
Background
Absorbent personal care articles such as diapers, sanitary napkins,
incontinence
pads and the like may be secured around a wearer or to an undergarment to hold
the
article in proper position during use. These articles frequently employ
adhesive.tabs,
so wings or flaps, garment attachment adhesives and/or similar systems. If the
article is
secured to an undergarment, it may employ wings or flaps that use adhesive to
secure the
end of the wing or flap to the undergarment.
Even with the combination of wings/flaps and garment attachment adhesive,
users
may encounter difficulty keeping the article in position. This problem is
particularly
i5 apparent when the user is physically active or when heat, moisture and/or
humidity
weaken the adhesive used to secure the article.
While different types of attachment systems such as belts, snaps or the like
are
known, these systems increase the cost and complexity of the article as well
as difficulty
for the user to attach or apply the absorbent article.
go Mechanical fastening systems appear on some commercially available personal
care articles. Typically, a conventional mechanical fastening system of the
hook and loop
type is used on flaps or wings of a product. However, these conventional
systems may
become disengaged when stresses are applied to the article over time. These
stresses
can be caused by a wide range of movements by the wearer, unusual movements,
25 intense activity such as exercise, and/or bunching and twisting of the
personal care
product.
Summary
The present invention addresses the problems discussed above by providing a
3 o selectively releasable, interengaging fastening system that may be used
for a variety of
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articles such as, for example, shoes, garments, disposable absorbent products
such as
disposable diapers, sanitary napkins, incontinence products and the like.
The fastening system includes a first fastener component that can constitute
at
least a first portion of an article. The first fastener component includes an
engagement
s section having a plurality of substantially non-isotropic engagement members
such that
the engagement section has an axis of substantially maximal engagement.
The fastening system also includes a cooperating fastener component that may
constitute at least a second portion of an article such that the first and
second portions of
the article are capable of being joined by movement of the respective
components
io together generally along an attachment direction into an overlapping and
interengaging
configuration.
According to the present invention, the first fastener component is oriented
so its
axis of substantially maximal engagement is generally orthogonal to the
attachment
direction. While the inventors should not be held to any particular theory of
operating, it is
15 believe that this configuration causes the first fastener component to
become more
interengaged with the cooperating fastener component as the article is
subjected to
various forces such as, for example, the type of forces encountered by the
fastening
system when used on a disposable personal care product that is worn.
In an aspect of the invention, each substantially non-isotropic engagement
a o member may have a stem portion with a distal end region and a securement
element
disposed at the distal end region of its corresponding stem portion.
Desirably, the engagement section has an axis of maximal engagement and a
generally perpendicular axis of minimal engagement.
In one embodiment of the invention, the cooperating fastener component may be
substantially non-isotropic and includes an axis of substantially maximal
engagement. For
example, the axis of substantially maximal engagement of the substantially non-
isotropic
engagement section and the axis of substantially maximal engagement of the
substantially non-isotropic cooperating fastener component may both be
substantially
parallel and each may be oriented generally orthogonal to the attachment
direction.
3 o According to the invention, at least one of the first portion and the
second portion
of the article on which the fastening system is placed or included may be a
segment
having a fixed end attached to an article body and a free end.
Generally speaking, the cooperating fastener component may be a loop material
such as, for example, a woven, knit or a nonwoven loop material. For example,
the
35 nonwoven loop material may be a pattern unbonded material such as, for
example, the
material described in U.S. Patent Nos. 5,858,515 and/or 5,763,041, the
contents of which
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are incorporated herein by reference.
In an aspect of the invention, fastening system can also be used to secure an
article in a configuration convenient for disposal.
In another aspect of the invention, the fastening system also provides ease of
use
or application benefits. In particular, the wings may be engaged on the
topsheet side or
body side of the sanitary napkin or incontinence article while the peel strip
protecting the
garment adhesive is removed. The article may then me placed in position on an
undergarment and then the wings may be engaged.
The present invention also encompasses an article that includes the fastening
to system. The article may have a lengthwise longitudinal direction, a lateral
cross-direction,
and a longitudinally extending medial line. The article may include a first
article portion; a
second article portion; and at least one selectively releasable, interengaging
fastener
system for securing the first article portion to the second article portion as
described
herein.
i5 The selectively releasable, interengaging fastener system may include:
(a) at least one first fastener component that may form at least one section
of the first
article portion, the first fastener component including an engagement section
having a
plurality of substantially non-isotropic engagement members such that the
engagement
section has an axis of substantially maximal engagement; and (b) at feast one
~o cooperating fastener component that may form at feast one section of the
second article
portion such that the first and second article portions are capable of being
joined by
movement of the respective components together generally along an attachment
direction
into an overlapping and interengaging configuration. According to the present
invention,
the first fastener component is oriented so its axis of substantially maximal
engagement is
a5 generally orthogonal to the attachment direction.
Desirably, the first fastener component may extend across the width and/or
length
dimension of the first article portion. For example, if the first article
portion is a wing or
flap, the first fastener component may extend across the wing or flap
generally along the
longitudinal axis of the product. More desirably, the first fastener component
may be a .
3 o flexible component that extends across the wing or flap and is flexible
enough to fold,
bend or otherwise flex with the flap or wing.
According to an embodiment of the present invention, configuring a flexible
first
fastener component to extend across at least the longitudinal direction or
dimension of a
relatively more flexible wing or flap helps alleviate twisting of the flaps
resulting in wear,
35 wrinkling and fastener failure due to the fastener attachment system being
too limp or
floppy. Moreover, extending a flexible first fastener component across at
least the
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longitudinal direction or dimension of a relatively more flexible wing or flap
avoids
problems associated with a small, discrete first fastener component centered
on the flap.
Such a small, discrete first fastener component tends to develop a moment
centered on
the fastener (which serves as an axis) when forces orthogonal to the
longitudinal direction
or dimension are applied through normal use. This typically leads to twisting
and wrinkling
of the flaps and tends to reduce fit-dependent performance of a personal care
product
incorporating such a fastening system.
The same orthogonal forces are present with the present invention that
utilizes a
flexible first fastener component that extends substantially across the
longitudinal
Zo dimension or direction of a relatively more flexible wing or flap. However,
when the
moment forms with the "substantially continuous" first fastener component in
place, the
moment is dampened by a static force in the opposite direction. This reduces
the twisting
and wrinkling of the flaps in absorbent personal care products when compared
to flaps in
absorbent personal care products having the same construction but with the
"substantially
continuous" first fastener component being replaced by a small, discrete first
fastener
component.
The article may further include substantially non-isotropic engagement members
having a stem portion with a distal end region and a securement element
disposed at the
distal end region of its corresponding stem portion. The engagement section of
the first
~ o fastener component may have an axis of maximal engagement and a generally
perpendicular axis of minimal engagement. The cooperating fastener component
may
also be substantially non-isotropic and have an axis of substantially maximal
engagement.
At least one of the first article portion and the second article portion may
be a tab,
ear, flap or wing-like element or segment having a free end and a fixed end
attached to an
~5 article body.
In one embodiment, the first article portion may provide a first waistband
portion.
The second article portion may provide a second waistband portion. The article
may also
have an intermediate portion which interconnects said first and second
waistband
portions. The article may further include a backsheet layer; a substantially
liquid-
3 o permeable topsheet layer; and an absorbent body sandwiched between said
backsheet
layer and topsheet layer. Generally speaking, this article may be in the form
of a
disposable diaper, incontinence pant, training pant or similar structure.
In yet another embodiment, the first article portion and the second article
portion
each may provide respective first and second flap portions, each flap portion
having a free
35 end and a fixed end attached to an intermediate portion which interconnects
the first and
second flap portions. The article may further include a backsheet layer;
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a substantially liquid-permeable topsheet layer; and an absorbent body
sandwiched
between said backsheet layer and topsheet layer. Generally speaking, this
article may be
in the form of a sanitary napkin, incontinence pad or similar structure.
Of course, the fastening system may also be adapted to secure the article in a
s configuration convenient for disposal.
The present invention also encompasses a selectively releasable, interengaging
fastening system for a disposable sanitary napkin, The fastening system
includes a first
fastener component that may form at least a first portion of the sanitary
napkin. The first
fastener component may include an engagement section having a plurality of
substantially
to non-isotropic engagement members such that the engagement section has an
axis of
substantially maximal engagement. The fastening system may also include a
cooperating
fastener component that may form at least a second portion of the sanitary
napkin such
that the first and second portions of the sanitary napkin are capable of being
joined by
movement of the respective components together generally along an attachment
direction
15 into an overlapping and interengaging configuration. According to the
invention, the first
fastener component is oriented so its axis of substantially maximal engagement
is
generally orthogonal to the attachment direction.
In an embodiment of the invention, the first portion and the second portion of
the
sanitary napkin may each provide respective first and second flap portions of
the sanitary
a o napkin. Each flap portion may have a free end and a fixed end attached to
an
intermediate portion that interconnects the first and second flap portions.
The sanitary
napkin may further include a backsheet layer; a substantially liquid-permeable
topsheet
layer; and an absorbent body sandwiched between said backsheet layer and
topsheet
layer.
25 The present invention also encompasses a sanitary napkin that includes the
selectively releasable, interengaglng fastening system described herein.
In an embodiment, the selectively releasable, interengaging fastening system
may
include a first wing extending from the first longitudinal edge of the
sanitary napkin and a
second wing extending from the second longitudinal edge of the sanitary
napkin. Each
3 o wing may have a fixed end and a free end.
A first fastener component may form at least a portion of at least the first
wing.
The first fastener component may an engagement section having a plurality of
substantially non-isotropic engagement members such that the engagement
section has
an axis of substantially maximal engagement.
35 A cooperating fastener component may form at least a portion of at least
the
second wing such that the first and second wings of the sanitary napkin are
capable of
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being joined by movement of the respective components together generally along
an
attachment direction into an overlapping and interengaging confiiguration.
According to the
invention, the first fastener component is oriented so its axis of
substantially maximal
engagement is generally orthogonal to the attachment direction.
. In an aspect of the invention, both the first wing and the second wing may
include
the first fastener component and the cooperating fastener component. In
another
aspect of the invention, at least one wing includes perforation lines adjacent
its fixed end
to provide quick removal of the napkin by tearing the wing along the
perforation lines.
The present invention is also directed to a selectively releasable,
interengaging
to fastening system for a disposable personal care product, in which the
fastening system
includes: a first fastener component comprising an engagement section having a
plurality
of engagement members; and a cooperating fastener component; such that the
fastening
system is adapted to become more interengaged as the disposable personal care
product
is worn.
'15
Brief Description of the Drawings
The present invention will be more fully understood and further advantages
will
become apparent when reference is made to the following detailed description
of the
ao invention and the drawings, in which:
FIG. 1A is an illustration of an exemplary article incorporating an exemplary
fastening system of the invention;
FIG. 1 B is an illustration of an exemplary article incorporating an exemplary
fiastening system of the invention;
25 FIG. 1 C is an illustration of an exemplary article incorporating an
exemplary
fastening system of the invention as it is used with an undergarment;
FIG. 1 D is an illustration of an exemplary article incorporating an exemplary
fastening system of the invention - with the backsheet of the article facing
upward ;
FIG. 1 D' is an illustration of an exemplary article incorporating an
exemplary
3 o fastening system of the invention - with the backsheet of the article
facing upward;
FIG. 1 E is an illustration of a portion of an exemplary article incorporating
an
exemplary fastening system ofi the invention - with the backsheet ofi the
article facing
upward;
FIG. 2A is an illustration of an exemplary article incorporating an exemplary
35 fastening system of the invention.
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FIG. 2B is an illustration of an exemplary article incorporating an exemplary
fastening system of the invention as it would be fastened to form a diaper,
training pant or
large incontinence article.
FIG. 3A is an illustration of an exemplary, non-isotropic engagement member
which
s can be employed with the present invention;
FIG. 3B is an illustration of an exemplary, non-isotropic engagement member
which
can be employed with the present invention;
FIG. 3B' representatively shows a top view of the engagement member of Fig.
3B;
FIG. 3C is an illustration of an exemplary, non-isotropic engagement member
which
to can be employed with the present invention;
FIG. 3C' representatively shows a top view of the engagement member of Fig.
3C;
FIG. 3D is an illustration of an exemplary, non-isotropic engagement member
which
can be employed with the present invention;
FIG. 3E is an illustration of an exemplary, non-isotropic engagement member
which
is can be employed with the present invention;
FIGS. 4A-B are graphical representations of data in Table 1;
FIGS. 5A-B are graphical representations of data in Table 1;
FIGS. 6A-B are photomicrographs of an exemplary , non-isotropic engagement
member which can be employed with the present invention;
ao FIGS. 7 and 8 are photomicrographs of exemplary cooperating fastener
members
(e.g., loop materials) that may be used with the present invention;
FIG. 9 is an illustration of an aspect of an interengaging fastening system;
FIG. 10 is an illustration of an aspect of the present invention.
as Detailed Description of the Invention
The various aspects and embodiments of the invention will be described in the
context of a disposable absorbent article, such as a sanitary napkin or a
disposable
diaper. It is, however, readily apparent that the present invention could also
be employed
with other articles, such as caps, gowns, shoe covers, feminine care articles,
children's
30 training pants, incontinence garments and the like. Typically, the
disposable articles are
intended for limited use and are not intended to be laundered or otherwise
cleaned for
reuse. A disposable diaper, for example, is discarded after it has become
soiled by the
wearer.
With reference to the Figures, an article, such as a sanitary napkin 10
illustrated in
35 FIGS. 1A-E (or a disposable diaper 10' illustrated in FIGS. 2A-B) has a
lengthwise,
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longitudinal direction 26, a lateral cross-direction 24, and a longitudinally
extending medial
line 40. The article includes a first article portion, a second article
portion and at least one
fastener 36 for securing the first article portion to the second article
portion. Such
securement can, for example, be configured to thereby hold the article on a
wearer. The
s fastener desirably includes at least one, first fastener component 70
attached to an
appointed section of the first (or second) article portion, and a cooperating
fastener
component 72 attached to the second (or first) article portion. The first
fastener
component 70 includes an engagement section having a first plurality of
engagement
members 56. Each engagement member 56 has a stem portion 58 with a distal end
so region 44, and has at least one securement element 60 disposed at its
corresponding
distal end region. The plurality of engagement members has an arrangement
pattern of
their securement elements. It is contemplated that multiple pluralities of
engagement
members, each with different arrangement pattern of their securement elements,
may be
used.
i5 Another aspect of the invention can provide an article in which the
fastener
component may include an engagement section having a plurality of non-
isotropic
engagement members. Each non-isotropic engagement member can have a stem
portion
58 with a distal end portion 44, and a direction-dependent securement element
60 which
is non-isotropically disposed at the distal end region of its corresponding
stem portion 58
a o to provide a non-isotropic engagement opening. The plurality of non-
isotropic
engagement members can have an alignment pattern of their engagement openings.
It is
contemplated that multiple pluralities of non-isotropic engagement members may
be used
and that different alignment patterns of their engagement openings are
possible.
In particular configurations, a majority of the plurality of non-isotropic
engagement
as members have their engagement openings directed substantially orthogonal to
an
attachment direction. Generally speaking, the attachment direction is the
direction in
which the respective first and second portions of the article are brought
together into an
overlapping and interengaging relationship. Thus, in FIGS. 1 and 2, the
attachment ,
direction is generally a direction having a cross-directional vector-component
along the
30 lateral direction 24 and toward the medial line 40 of the article.
Accordingly, the plurality of
non-isotropic engagement members would have their engagement openings directed
substantially parallel with the medial line 40 of the article.
In the various aspects of the invention, the individual engagement members are
typically flexible and resilient, but will substantially retain their initial
shape during ordinary
35 use. When flexed or deformed during ordinary use, the engagement members
will
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substantially avoid plastically deforming to sustain the deformation, and
will, instead,
substantially return or "spring-back" to their original orientations and
shape.
The various aspects (individually and in combination) of the present invention
can
advantageously help to better maintain the desired fit around the wearer. For
example,
s the aspects of the invention can help reduce the sagging and drooping of the
crotch
region of the garment, and can help reduce roll-over and drooping at the waist
region. The
incorporation of the various aspects of the fastening system of the invention
can provide
improved securement with greater resistance to premature pop-opens, and can
also help
provide improved fit, greater comfort and reduced irritation of the wearer's
skin.
to The article of the invention can, for example, be a such as a disposable
diaper. In
desired aspects of the invention, the first article portion can provide a
first, back waistband
portion, and the second article portion can provide a second, front waistband
portion. In
addition, the article can have an intermediate or crotch portion which
interconnects
between the first and second waistband portions, respectively. The diaper can
further
is include a backsheet layer, a liquid permeable topsheet layer connected and
assembled in
facing relation with the backsheet layer, and an absorbent structure, such as
a structure
which includes absorbent body. 'The absorbent structure is sandwiched between
the
backsheet and topsheet layers, and is operably held therebetween. A fastening
system,
such as the system including fastener, is typically constructed and arranged
to
ao interconnect the first waistband portion with the second waistband portion
to hold the
article on a wearer. The fastening system can be operatively configured to
join the first,
back waistband portion in an overlapping relation with the second, front
waistband
portion in a back-to-front arrangement to thereby encircle the wearer's body
and hold the
diaper secure on the wearer during use. Optionally, the fastening system can
employ
25 fasteners that are configured to join the front waistband portion in an
overlapping relation
with the back waistband portion in a front-to-back arrangement to secure the
diaper. In
such optional arrangements, the front waistband region may be identified as
the first
waistband portion and the rear waistband region may be identified as the
second
waistband portion.
3o FIGS. 1A-E are illustrations of an exemplary sanitary napkin with fasteners
36 in the
form of wings or flaps. At least one first fastener component 70 is attached
to the wing 36
and at least one cooperating fastener component 72 is attached to the opposite
wing 36.
In some embodiments of the invention, the first fastener component 70 and the
cooperating fastener component 72 may be attached to each wing such that the
wings
35 may be fastened without concern for overlapping the wings in any particular
order. In
other yet embodiments, the wing may be formed partially or entirely of the
cooperating
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fastener component 72. FIG. 1 C is an illustration of the sanitary napkin with
its wings 36
or flaps secured around an undergarment or panty "P". The arrows labeled "A"
generally
represent the attachment direction. The arrows labeled "O" generally represent
the
direction that is orthogonal to the attachment direction. It should be
understood that this
s orthogonal direction is thought to be generally or substantially along or in
the plane of the
article although in some specific cases, it include a minor Z-direction
component.
According to the invention, the first fastener component should be configured
to
have an axis of maximal engagement. This can be accomplished by utilizing a
plurality of
engagement members 56 that are non-isotropic (i.e., anisotropic) or non-
symmetric.
to When the axis of maximal engagement of the first fastener component is
oriented to be
generally orthogonal to the attachment direction (that is, the direction each
fastener
component is generally brought together to effect overlapping engagement), it
has been
unexpectedly found that the fastening system is adapted to become more
interengaged
as the product is worn. For example, peel force and shear force as determined
utilizing
15 standard test procedures prior to wearing the article is greater for
fastening systems in
which the axis of maximal engagement of the first fastener component is
oriented in the
attachment direction and lower for fastening systems in which the axis of
maximal
engagement ~of the first fastener component is oriented orthogonal to the
attachment
direction.
z o When the peel force and the shear force were measured after use, the
values
increased for both orientations. However, the peel force and sheer force
values measured
for fastening systems in which the axis of maximal engagement of the first
fastener
component is oriented orthogonal to the attachment direction were greater than
those
measured for fastening systems in which the axis of maximal engagement of the
first
z5 fastener component is oriented in the attachment direction.
Data showing this result is in attached Table 1 and is shown graphically in
FIGS.
4A-B and 5A-B.
The following is a brief description of the orientation direction with respect
to the
lengthwise, longitudinal direction 26 and the lateral cross-wise direction
depicted in FIGS.
30 1A, 1 D, and 1 D'. In one exemplary sanitary napkin, the orienting the axis
of maximal
engagement of the first fastener component in the attachment direction meant
orienting
the first fastener component so its axis of maximal engagement was in the
cross-machine
direction or the lateral cross-direction 24 shown in FIGS. 1A, 1 D, and 1 D'.
Thus, for that
sanitary napkin, the orienting the axis of maximal engagement of the first
fastener
35 component generally orthogonal to the attachment direction meant orienting
the first
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fastener component so its axis of maximal engagement was in the machine
direction or
the lengthwise, longitudinal direction 26 shown in FIGS. 1A, 1 D and 1 D'.
FIG. 1 D shows an embodiment of the invention in which a first fastener
component
70 is affixed to a wing or flap 36 and a cooperating fastener component 72 is
affixed or
s integral with a corresponding wing or flap 36. FIG 1 D' illustrates an
embodiment in which
a first fastener component is affixed to each wing or flap 36 and a
cooperating fastener
component is present on each wing or flap 36 as well. FIG. 1 E illustrates the
embodiment
in FIG. 1 D' such that the first fastener components 70 and the cooperating
fastener
components 72 on each flap or wing 36 are more visible. More particularly,
FIG. 1 E shows
i o a pair of wings or flaps 36 each having a first fastener component 70
affixed to the wing
so as to face the baffle or peel strip of an article as well as a cooperating
fastener
component 72 affixed to or integral with wing so as to face the opposite side
of the wing
(i.e., the side of the wind facing away from the baffle or peel strip).
FIG. 2 is an illustration of an exemplary diaper with fasteners 36 in the form
of tabs
is or ears extending from a waistband section of the diaper. At least one
first fastener
component is attached to the ear 36 and at least one cooperating fastener
component 72
is attached to a corresponding portion of the diaper so that the diaper can be
configured
for wearing as shown, for example, in FIG. 2A. The arrows labeled "A"
generally
represent the attachment direction.
~ o The diaper 10 can typically include a porous, liquid permeable topsheet
28; a
substantially liquid impermeable backsheet 30; an absorbent body structure 32
positioned
and connected between the topsheet and backsheet; a surge management portion
46
located adjacent the absorbent structure; and a system of efastomeric
gathering
members, such as a system including leg elastics 34 and waist elastics 42. The
surge
as management portion is positioned in.a liquid communication with an
appointed storage or
retention portion of the absorbent structure, and the topsheet 28, backsheet
30, absorbent
structure 32, surge management portion 46 and elastic members 34 and 42 may be
assembled together into a variety of well-known diaper configurations. The
diaper can
additionally include a system of containment flaps 62, and a system of side
panel or ear
3 o region members 38, which may be elasticized or otherwise rendered
elastomeric.
Various techniques for forming the desired fastening systems are described in
U.S.
Patent No. 5,399,219 of T. Roessler et al., entitled METHOD FOR MAKING A
FASTENING SYSTEM FOR A DYNAMIC FITTING DIAPER which issued March 21, 1995
(attorney docket No. 11,186); in U.S. Patent Application Serial No. 286,086 of
D. Fries,
35 entitled A PROCESS FOR ASSEMBLING ELASTICIZED EAR PORTIONS and filed
August 3, 1994 (attorney docket No. 11,169) which corresponds to U.S. Patent
No.
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5,540,796; and in U.S. Patent Application Serial No. 08/415,383 of D. Fries,
entitled AN
ASSEMBLY PROCESS FOR A LAMINATED TAPE and filed April 3, 1995 (attorney
docket No. 11,950) which corresponds to U.S. Patent No. 5,595,618. The
disclosures of
the above-described documents are incorporated herein by reference in a manner
that is
consistent (not in conflict) herewith.
The diaper 10 generally defines the longitudinally extending length direction
26 and
the laterally extending width direction 24, as representatively shown in Figs.
1 and 2. The
diaper may have any desired shape, such as rectangular, I-shaped, a generally
hourglass shape, or a T-shape. With the T-shape, the crossbar of the "T" may
comprise
io the front waistband portion of the diaper, or may alternatively comprise
the rear waistband
portion of the diaper.
The topsheet 28 and backsheet 30 may be generally coextensive, and may have
length and width dimensions which are generally larger than and extend beyond
the
corresponding dimensions of the absorbent structure 32 to provide for the
corresponding
i5 side margins 20 and end margins 22. Optionally, the topsheet and backsheet
layers may
not be coextensive. The topsheet 28 is operatively associated with and
superimposed on
backsheet 30, thereby defining the periphery of the diaper. The waistband
regions
comprise those portions of the diaper, which when worn, wholly or partially
cover or
encircle the waist or mid-lower torso of the wearer. The intermediate, crotch
region 16
a o lies between and interconnects the waistband regions 14 and 12, and
comprises that
portion of the diaper which, when worn, is positioned between the legs of the
wearer and
covers the lower torso of the wearer. Thus, the intermediate crotch region 16
is an area
where repeated fluid surges typically occur in the diaper or other disposable
absorbent
article.
as The backsheet 30 can typically be located along an outer-side surFace of
the
absorbent body 32 and may be composed of a liquid permeable material, but
desirably
comprises a material which is configured to be substantially impermeable to
liquids. For
example, a typical backsheet can be manufactured from a thin plastic film, or
other
flexible, substantially liquid-impermeable material. As used in the present
specification,
3 o the term "flexible" refers to materials which are compliant and which will
readily conform to
the general shape and contours of the wearer's body. Backsheet 30 prevents the
exudates contained in absorbent body 32 from wetting articles, such as
bedsheets and
overgarments, which contact diaper 10. In particular embodiments of the
invention,
backsheet 30 can include a film, such as a polyethylene film, having a
thickness of from
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about 0.012 millimeters (0.5 mil) to about 0.051 millimeters (2.0 mils). For
example, the
backsheet film can have a thickness of about 1.25 mil.
Alternative constructions of the backsheet may comprise a woven or non-woven
fibrous web layer which has been totally or partially constructed or treated
to impart the
s desired levels of liquid impermeability to selected regions that are
adjacent or proximate
the absorbent body. For example, the backsheet may include a gas-permeable,
nonwoven fabric layer laminated to a polymer film layer which may or may not
be gas-
permeable. Other examples of fibrous, cloth-like backsheet materials can
comprise a
stretch thinned or stretch thermal laminate material composed of a 0.6 mil
(0.015 mm)
Zo thick polypropylene blown film and a 0.7 ounce per square yard (23.8 gsm)
polypropylene
spunbond material (2 denier fibers). A material of this type forms the
outercover of a
HUGGIES SUPREME disposable diaper, which is commercially available from
Kimberly-Clark Corporation. The backsheet 30 typically provides the outer
cover of the
article. Optionally, however, the article may include a separate outer cover
component
is member which is additional to the backsheet.
The backsheet 30 may alternatively include a micro-porous, "breathable"
material
which permits gases, such as water vapor, to escape from the absorbent body 32
while
substantially preventing liquid exudates from passing through the backsheet.
For
example, the breathable backsheet may be composed of a microporous polymer
film or a
ao nonwoven fabric which has been coated or otherwise modified to impart a
desired level of
liquid impermeability. For example, a suitable microporous film can be a PMP-1
material,
which is available from Mitsui Toatsu Chemicals, Inc., a company having
offices in
Tokyo, Japan; or an XKO-8044 polyolefin film available from 3M Company of
Minneapolis, Minnesota. The backsheet may also be embossed or otherwise
provided
~5 with a pattern or matte finish to exhibit a more aesthetically pleasing
appearance.
In the various configurations of the invention, where a component such as the
backsheet 30 or the containment flaps 62 are configured to be permeable to gas
while
having a resistance and limited permeability to aqueous liquid, the liquid
resistant material
can have a construction which is capable of supporting a hydrohead of at least
about
30 45 cm of water substantially without leakage therethrough. A suitable
technique for
determining the resistance of a material to liquid penetration is Federal Test
Method
Standard FTMS 191 Method 5514, 1978, or an equivalent thereof.
The topsheet 28 presents a body-facing surface which is compliant, soft-
feeling,
and non-irritating to the wearer's skin. Further, the topsheet 28 can be less
hydrophilic
35 than absorbent body 32, and is sufficiently porous to be liquid permeable,
permitting liquid
to readily penetrate through its thickness to reach the absorbent body. A
suitable
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topsheet layer 28 may be manufactured from a wide selection of web materials,
such as
porous foams, reticulated foams, apertured plastic films, natural fibers (for
example, wood
or cotton fibers), synthetic fibers (for example, polyester or polypropylene
fibers), or a
combination of natural and synthetic fibers. The topsheet layer 28 is
typically employed to
help isolate the wearer's skin from liquids held in absorbent body 32.
Various woven and nonwoven fabrics can be used for topsheet 28. For example,
the topsheet may be composed of a meltblown or spunbonded web of the desired
fibers,
and may also be a bonded-carded-web. The various fabrics can be composed of
natural
fibers, synthetic fibers or combinations thereof.
io For the purposes of the present description, the term "nonwoven web" means
a web
of fibrous material which is formed without the aid of a textile weaving or
knitting process.
The term "fabrics" is used to refer to all of the woven, knitted and nonwoven
fibrous
webs.
The topsheet fabrics may be composed of a substantially hydrophobic material,
and
15 the hydrophobic material may optionally be treated with a surfactant or
otherwise
processed to impart a desired level of wettability and hydrophilicity. In a
particular
embodiment of the invention, topsheet 28 is a nonwoven, spunbond polypropylene
fabric
composed of about 2.8 - 3.2 denier fibers formed into a web having a basis
weight of
about 22 gsm and density of about 0.06 gm/cc. The fabric can be surface
treated with an
20 operative amount of surfactant, such as about 0.28% TRITON X-102
surfactant. The
surfactant can be applied by any conventional means, such as spraying,
printing, brush
coating or the like.
The topsheet 28 and backsheet 30 are connected or otherwise associated
together
in an operable manner. As used herein, the term "associated" encompasses
configurations in which topsheet 28 is directly joined to backsheet 30 by
affixing topsheet
28 directly to backsheet 30, and configurations wherein topsheet 28 is
indirectly joined to
backsheet 30 by affixing topsheet 28 to intermediate members which in turn are
affixed to
backsheet 30. Topsheet 28 and backsheet 30 can, for example, be joined to each
other in
at least a portion of the diaper periphery by suitable attachment mechanisms
(not shown)
3 o such as adhesive bonds, sonic bonds, thermal bonds, pinning, stitching or
any other
attachment technique known in the art, as well as combinations thereof. For
example, a
uniform continuous layer of adhesive, a patterned layer of adhesive, a sprayed
pattern of
adhesive or an array of separate lines, swirls or spots of construction
adhesive may be
used to affix the topsheet 28 to the backsheet 30. It should be readily
appreciated that
35 the above-described attachment means may also be employed to suitably
interconnect,
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assemble and/or affix together the various other component parts of the
articles which are
described herein.
The absorbent body 32 provides an absorbent structure which can include a
retention portion, such as the representatively shown absorbent pad composed
of
selected hydrophilic fibers and high-absorbency particles, for holding and
storing
absorbed liquids and other waste materials. The absorbent body is positioned
and
sandwiched between the topsheet 28 and backsheet 30 to form the diaper 10. The
absorbent body has a construction which is generally compressible,
conformable, non-
irritating to the wearer's skin, and capable of absorbing and retaining body
exudates. It
to should be understood that, for purposes of this invention, the absorbent
body structure
may comprise a single, integral piece of material, or alternatively, may
comprise a plurality
of individual separate pieces of material which are operably assembled
together.
Various types of wettable, hydrophilic fibrous material can be used to form
the
component parts of absorbent body 32. Examples of suitable fibers include
naturally
is occurring organic fibers composed of intrinsically wettable material, such
as cellulosic
fibers; synthetic fibers composed of cellulose or cellulose derivatives, such
as rayon
fibers; inorganic fibers composed of an inherently wettable material, such as
glass fibers;
synthetic fibers made from inherently wettable thermoplastic polymers, such as
particular
polyester or polyamide fibers; and synthetic fibers composed of a nonwettable
a o thermoplastic polymer, such as polypropylene fibers, which have been
hydrophilized by
appropriate means. The fibers may be hydrophilized, for example, by treatment
with
silica, treatment with a material which has a suitable hydrophilic moiety and
is not readily
removable from the fiber, or by sheathing the nonwettable, hydrophobic fiber
with a
hydrophilic polymer during or after the formation of the fiber. For the
purposes of the
25 present invention, it is contemplated that selected blends of the various
types of fibers
mentioned above may also be employed.
As used herein, the term "hydrophilic" describes fibers or the surfaces of
fibers
which are wetted by the aqueous liquids in contact with the fibers. The degree
of wetting
of the materials can, in turn, be described in terms of the contact angles and
the surface
3o tensions of the liquids and materials involved. Equipment and techniques
suitable for
measuring the wettability of particular fiber materials or blends of fiber
materials can be
provided by a Cahn SFA-222 Surface Force Analyzer System, or a substantially
equivalent system. When measured with such system, fibers having contact
angles less
than 90° are designated "wettable", while fibers having contact angles
greater than 90°
35 are designated "nonwettable".
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The absorbent body structure 32 can comprise a matrix of hydrophilic fibers,
such
as a web of cellulosic fluff, mixed with particles of high-absorbency
material. In particular
arrangements, absorbent body 32 may comprise a mixture of superabsorbent
hydrogel-
forming particles and synthetic polymer meltblown fibers, or a mixture of
superabsorbent
s particles with a fibrous coform material comprising a blend of natural
fibers and/or
synthetic polymer fibers. The superabsorbent particles may be substantially
homogeneously mixed with the hydrophilic fibers, or may be nonuniformly mixed.
For
example, the concentrations of superabsorbent particles may be arranged in a
non-step-
wise gradient through a substantial portion of the thickness (z-direction) of
the absorbent
so structure, with lower concentrations toward the bodyside of the absorbent
body and
relatively higher concentrations toward the outerside of the absorbent
structure. Suitable
z-gradient configurations are described in U.S.P. 4,699,823 issued October 13,
1987 to
Kellenberger et al., the entire disclosure of which is incorporated herein by
reference in a
manner that is consistent (not in conflict) with the present description.
Alternatively, the
Zs concentrations of superabsorbent particles may be arranged in a non-step-
wise gradient,
through a substantial portion,of the thickness (z-direction) of the absorbent
structure, with
higher concentrations toward the bodyside of the absorbent body and relatively
lower
concentrations toward the outerside of the absorbent structure. The
superabsorbent
particles may also be arranged in a generally discrete layer within the matrix
of hydrophilic
ao fibers. In addition, two or more different types of superabsorbent may be
selectively
positioned at different locations within or along the fiber matrix.
The high-absorbency material may comprise absorbent gelling materials, such as
superabsorbents. Absorbent gelling materials can be natural, synthetic
and.modified
natural polymers and materials. In addition, the absorbent gelling materials
can be
~s inorganic materials, such as silica gels, or organic compounds such as
cross-linked
polymers. The term "cross-linked" refers to any means for effectively
rendering normally
water-soluble materials substantially water insoluble but swellable. Such
means can
include, for example, physical entanglement, crystalline domains, covalent
bonds, ionic
complexes and associations, hydrophilic associations, such as hydrogen
bonding, and
3 o hydrophobic associations or Van der Waals forces.
Examples of synthetic absorbent gelling material polymers include the alkali
metal
and ammonium salts of poly(acrylic acid) and poly (methacrylic acid),
poly(acrylamides),
polyvinyl ethers), malefic anhydride copolymers with vinyl ethers and alpha-
olefins,
polyvinyl pyrrolidone), poly(vinylmorpholinone), polyvinyl alcohol), and
mixtures and
3s copolymers thereof. Further polymers suitable for use in the absorbent body
include
natural and modified natural polymers, such as hydrolyzed acrylonitrile-
grafted starch,
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acrylic acid grafted starch, methyl cellulose, chitosan, carboxymethyl
cellulose,
hydroxypropyl cellulose, and the natural gums, such as alginates, xanthan gum,
locust
bean gum and the like. Mixtures of natural and wholly or partially synthetic
absorbent
polymers can also be useful in the present invention. Other suitable absorbent
gelling
s materials are disclosed by Assarsson et al. in U.S. Patent No. 3,901,236
issued
August 26, 1975. Processes for preparing synthetic absorbent gelling'polymers
are
disclosed in U.S. Patent No. 4,076,663 issued February 28, 1978 to Masuda et
al. and
U.S. Patent No. 4,286,082 issued August 25, 1981 to Tsubakimoto et al.
Synthetic absorbent gelling materials typically are xerogels which form
hydrogels
to when wetted. The term "hydrogel", however, has commonly been used to also
refer to
both the wetted and unwetted forms of the material.
With reference to the representative configurations shown in Figs. 1 and 2,
the
article can include a system of flap regions, wings, "ear" regions or ear
members. In
particular arrangements, each flap, wing or ear region or member may extend
laterally at
l5 the opposed, lateral ends of the article such as a diaper, incontinence pad
or sanitary
napkin.
In the various configurations of the invention, the ear, tab, flap or wing
regions may
be integrally formed with a selected article component. For example, ear, tab,
flap or wing
regions can be integrally formed from the layer of material which provides
backsheet layer
~o and/ or may be integrally formed from the material employed to provide
topsheet. In
alternative configurations, the ear, tab, flap or wing regions may be provided
by one or
more separately provided members that are connected and assembled to the
backsheet,
to the topsheet, in between the backsheet and topsheet, or in various fixedly
attached
combinations of such assemblies.
In particular configurations of the invention, each of the ear , tab, flap or
wing
regions may be formed from a separately provided piece of material which is
then suitably
assembled and attached to a selected portion of the article.
The ear, tab, flap or wing regions may be composed of a substantially non
elastomeric material, such as polymer films, woven fabrics, nonwoven fabrics
or the like,
3o as well as combinations thereof. In particular aspects of the invention,
ear, tab, flap or
wing regions may be composed of a substantially elastomeric material, such as
a stretch-
bonded-laminate (SBL) material, a neck-bonded-laminate (NBL) material, an
elastomeric
film, an elastomeric foam material, or the like, which is elastomerically
stretchable at least
along the lateral direction 24. For example, suitable meltblown elastomeric
fibrous webs
35 for forming ear , tab, flap or wing regions are described in U.S.P.
4,663,220 issued
May 5, 1987 to T. Wisneski et al., the entire disclosure of which is hereby
incorporated by
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reference. Examples of composite fabrics comprising at least one layer of
nonwoven
textile fabric secured to a fibrous elastic layer are described in European
Patent
Application EP 0 217 032 A2 published on April 8, 1987 which has the listed
inventors of
J. Taylor et al., the entire disclosure of which is hereby incorporated by
reference.
Examples of NBL materials are described in U.S. Patent No. 5,226,992 issued
July 13,
1993 to Mormon, the entire disclosure of which is hereby incorporated by
reference in a
manner that is consistent herewith.
As previously mentioned, various suitable constructions can be employed to
attach
the ear, tab, flap or wing regions to the selected portions of the article.
Particular
to examples of suitable constructions for securing a pair of elastically
stretchable members
to the lateral, side portions of an article to extend laterally outward beyond
the laterally
opposed side regions of the outer cover and liner components of an article can
be found
in U.S. Patent No. 4,938,753 issued July 3, 1990 to P. VanGompel et al., the
entire
disclosure of which is hereby incorporated by reference in a manner that is
consistent
15 herewith.
The illustrated ear, tab, flap or wing regions have a tapered, curved or
otherwise
contoured shape in which the longitudinal length of the relatively inboard
base region is
larger or smaller than the longitudinal length of its relatively outboard end
region.
Alternatively, the ear regions may have a substantially rectangular shape, and
optionally
a o may have a substantially trapezoidal shape.
In the various aspects and configurations of the invention, the fastening
mechanism
between the selected first fastener component and the selected, cooperating
fastener
component may be adhesive, cohesive, mechanical or combinations thereof. In
the
context of the present invention, a mechanical fastening system is a system
which
as includes a first fastener component and. cooperating fastener component
which
mechanically inter-engage to provide a desired securement.
Desirably, the first fastener component and cooperating fastener components
include complementary elements of a cooperatively interengaging mechanical
fastening
system. The mechanical fastener components can be provided by mechanical-type
3 o fasteners such as hooks, buckles, snaps, buttons and the like, which
include cooperating
and complementary, mechanically interlocking components.
As shown in the illustrated arrangements, for example, the mechanical
fastening
system may be a hook-and-loop type of fastening system. Such fastening systems
typically include engagement members having the form of a "hook" or hook-like,
male
35 component, and include a cooperating "loop" or loop-like, female component
which
engages and releasably interconnects with the hook component. Desirably, the
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interconnection is selectively releasable and re-attachable. Conventional
systems are, for
example, available under the VELCRO trademark. The hook element may be
provided by
a single-prong hook configuration, a multiple-prong hook configuration or by a
generally
continuous, expanded-head configuration, such as provided by a mushroom-head
type of
hook element. The loop element may be provided by a woven fabric, a nonwoven
fabric,
a knitted fabric, a perforated or apertured layer, and the like, as well as
combinations
thereof. The many arrangements and variations of such fastener systems have
been
collectively referred to as hook-and-loop fasteners.
A configuration which employs a selectively releasable, interengaging
mechanical
so fastening system can, for example, locate the first fastener component on
at least the
appointed mating or securing surface of the tab, flap or wing 36, and can
locate the
cooperating fastener component on the appointed engagement surface of the
appointed
tab, flap or wing 36. For example, with the representatively shown hook-and-
loop
fastener, the fastening component which is attached to the appointed mating or
securing
is surface of a fastener tab 36 may include a hook type of mechanical
engagement element,
and the complementary fastening component, which is operably joined and
attached to
the appointed surface of a fastener tab 36 can include a loop type of
fastening element.
It should also be readily apparent that, in the various configurations of the
invention, the relative positions and/or materials of the first fastening
component and its
ao cooperating, complementary fastening component can be transposed.
Examples of hook-and-loop fastening systems and components are described in
U.S.P. 5,019,073 issued May 28, 1991 to T. Roessler et al., the entire
disclosure of which
is hereby incorporated by reference in a manner that is consistent herewith.
Other
examples of hook-and-loop fastening systems are described in U.S. Patent
Application
as Serial No. 366,080 entitled HIGH-PEEL TAB FASTENER, filed December 28, 1994
by
G. Zehner et al. (attorney docket No. 11,571) which corresponds to U.S. Patent
No. 5,605,735; and U.S. Patent Application Serial No. 421,640 entitled MULTI-
ATTACHMENT FASTENING SYSTEM, filed April 13, 1995 by P. VanGompel et al.; the
entire disclosures of which are hereby incorporated by reference in a manner
that is
3 o consistent herewith. Examples of fastening tabs constructed with a carrier
layer are
described in U.S. Patent Application Serial No. 08/603,477 of A. Long et al.,
entitled
MECHANICAL FASTENING SYSTEM WITH GRIP TAB and filed March 6, 1996 (attorney
docket No. 12,563) which corresponds to U.S. Patent No. 5,624,429 which issued
April 29, 1997, the entire disclosure of which is hereby incorporated by
reference in a
s5 manner which is consistent herewith.
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With reference to Figs. 3 A-E, the appointed first fastener component 70 can
include a material having engagement members (e.g. the shown hook members)
which
project away from a base or substrate layer 110. Each engagement member
includes a
generally, up-standing stem portion 58 and a securement element 60. The stem
s portion 58 has a fixed end region 43, and a distal end region 44 which,
desirably, is
contiguously joined with the fixed end region. The fixed end region of the
stem portion is
operably attached to the substrate layer 110, and the distal end region is
operably
attached to its corresponding, associated securement element 60. The stem
portion 58 is
sufficiently rigid to maintain the appointed upright positioning and the
appointed directional
io alignment of the securement element 60 during the ordinary operation of the
first fastener
component in the fastener system. More particularly, the stem portion is
sufficiently
resistant to bending and twisting to operably maintain the desired upright
positioning and
directional alignment of the securement element. The substrate layer 110 has a
substrate
thickness 112, an engagement member surface 114, and an opposed substrate
mounting
15 surface 116. The selected engagement members are attached to the substrate
layer 110,
and project away from the engagement member surface 114.
As representatively shown in Figs. 3 A-E, particular aspects of the invention
may
incorporate non-isotropic engagement members where the non-isotropic
engagement
members are configured to provide a directional or direction-dependent
engagement with
ao the cooperating fastener component 72. In particular, the engagement
members can
exhibit at least one bias direction along which a selected fastening property,
such as peel
force, shear force or the like, has a relatively different value. For example,
the fastening
property may have at least one bias direction along which a fastening
property, such as
peel force, shear force or the like, has a relatively maximal value.
Similarly, the
25 engagement members can exhibit at least one bias direction along which the
selected
fastening property has a relatively minimal value. The direction of maximal
value may or
may not be substantially opposite to the direction of relatively minimal
value.
Thus, the non-isotropic engagement member may provide a greater (or lesser)
shear force value or peel force value depending upon the direction along which
the shear
3 o force or peel force value is determined. The non-isotropic feature may be
generated by
various suitable mechanisms, such as a difference in shape, size dimension,
contour,
length of projection, angle of projection, type of material, type of coating
or other
treatment, surface texture, surface topography, coefficient of friction,
cohesion or the like,
as well combinations thereof. The non-isotropic engagement member may have a
limited
35 degree of symmetry, such as a bilateral symmetry. Suitable non-isotropic
engagement
members can, for example, be provided by inverted-J shaped or generally T-
shaped
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engagement members. In contrast, substantially isotropic engagement members
may be
provided by mushroom shaped engagement members where the mushroom head is
substantially symmetrically distributed about its upstanding stem 'portion and
where the
appointed engagement opening is similarly substantially symmetrically
distributed about
its upstanding stem portion.
An example of a suitable micro-hook material is distributed under the
designations
VELCRO HTH 829 and VELCRO HTH 851and is available from VELCRO U.S.A., Inc., a
business having offices in Manchester, New Hampshire. The micro-hook material
can
have hooks in the shape of angled hook elements, and can be configured with a
hook
to density of about 264 hooks per square centimeter (about 1700 hooks per
square inch); a
hook height which is within the range of about 0.030 - 0.063 cm (about 0.012 -
0.025
inch); and a hook width which is within the range of about 0.007 to 0.022 cm
(about 0.003
to 0.009 inch). The hook elements are molded onto a base layer substrate
having a
thickness of about 0.0076 - 0.008 cm (about 0.003 - 0.0035 inch), and the
member of
hook material has a Gurley stiffness of about 12 mgf (about 12 Gurley units).
Other
suitable hook materials can include VELCRO HTH 858, VELCRO HTH 851 and VELCRO
HTH 863 hook materials.
For the purposes of the present invention, the various stiffness values are
determined with respect to a bending moment produced by a force which is
directed
z o perpendicular to the plane substantially defined by the length and width
of the component
being tested. A suitable technique for determining the stiffness values
described herein is
a Gurley Stiffness test, a description of which is set forth in TAPPI Standard
Test T 543
om-94 (Bending Resistance of Paper (Gurley type tester)). A suitable testing
apparatus is
a Gurley Digital Stiffness Tester; Model 4171-D manufactured by Teledyne
Gurley, a
business having offices in Troy, New York. For purposes of the present
description, the
stated Gurley stiffness values are intended to correspond to the values that
would be
generated by a "standard" sized sample. Accordingly, the scale readings from
the Gurley
stiffness tester are appropriately converted to the stiffness of a standard
size sample, and
are traditionally reported in terms of milligrams of force (mgf). Currently, a
standard
"Gurley unit" is equal to a stiffness value of 1 mgf, and may equivalently be
employed to
report the Gurley stiffness.
In the various aspects and configurations of the invention, the loop material
can be
provided by a nonwoven, woven or knit fabric. For example, a suitable loop
material
fabric can be composed of a 2 bar, warp knit fabric of the type available from
Guilford
Mills, Inc., Greensboro, North Carolina under the trade designation #34285, as
well as
other types of knit fabrics. Suitable loop materials are also available from
the
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3M Company, which has distributed a nylon woven loop under their SCOTCHMATE
brand. The 3M Company has also distributed a linerless loop web with adhesive
on the
backside of the web, and 3M knitted loop tape.
The loop material may also include a nonwoven fabric having continuous bonded
s areas defining a plurality of discrete unbonded areas. The fibers or
filaments within the
discrete unbonded areas of the fabric are dimensionally stabilized by the
continuous
bonded areas that encircle or surround each unbonded area, such that no
support or
backing layer of film or adhesive is required. The unbonded areas are
specifically
designed to afford spaces between fibers or filaments within the unbonded area
that
so remain sufficiently open or large to receive and engage hook elements of
the
complementary hook material. In particular, a pattern-unbonded nonwoven fabric
or web
may include a spunbond nonwoven web formed of single component or multi-
component
melt-spun filaments. At least one surface of the nonwoven fabric can include a
plurality of
discrete, unbonded areas surrounded or encircled by continuous bonded areas.
The
is continuous bonded areas dimensionally stabilize the fibers or filaments
forming the
nonwoven web by bonding or fusing together the portions of the fibers or
filaments that
extend outside of the unbonded areas into the bonded areas, while leaving the
fibers or
filaments within the unbonded areas substantially free of bonding or fusing.
The degree
of bonding or fusing within the bonding areas desirably is sufficient to
render the
~o nonwoven web non-fibrous within the bonded areas, leaving the fibers or
filaments within
the unbonded areas to act as "loops" for receiving and engaging hook elements.
Examples of suitable point-unbonded fabrics are described in U.S. Patent
Application Ser.
No. 754,419 entitled PATTERN-UNBONDED NONWOVEN WEB AND PROCESS FOR
MAKING THE SAME, by T. J. Stokes et al., and filed December 17, 1996 (attorney
docket
z5 No. 12,232); the entire disclosure of which is incorporated herein by
reference in a
manner that is consistent herewith.
As used herein, the term "spunbond web" refers to a web formed by extruding a
molten thermoplastic material as filaments from a plurality of fine, usually
circular,
capillaries with the diameter of the extruded filaments then being rapidly
reduced, for
3 o example, by fluid-drawing or other well known spunbonding mechanisms. The
production
of spunbond nonwoven webs is illustrated in patents such as Appel, et al.,
U.S. Patent No.
4,340,563.
In the various configurations of the invention, the loop material need not be
limited
to a discrete or isolated patch on the outward surface of the article.
Instead, the loop
35 material can be provided by a substantially continuous, outer fibrous layer
which is
assembled, integrated or otherwise joined to extend over a predetermined
surface area of
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the desired article. For example, the outer fibrous layer may be arranged to
extend over
substantially the total exposed surface area of a cloth-like outer cover
employed with the
article.
In the various configurations of the invention, the engagement force between
the
s selected first fastener component and its appointed and cooperating fastener
component
should be large enough and durable enough to provide an adequate securement of
the
article on the wearer during use. In particular arrangements, especially where
there are
sufficiently high levels of engagement shear force provided by the fastening
system, the
fastening engagement may provide a peel force value of not less than a minimum
of
so about 40 grams-force (gmf) per inch of the "width" of engagement between
the first and
cooperating fastener components. In further arrangements, the fastening
engagement
may provide a peel force value of not less than about 100 gmf/inch to provide
improved
advantages. In desired configurations, the fastening engagement may provide a
peel
force value of not less than about 200 gmf per inch of the "width" of
engagement between
z5 the first and cooperating fastener components . Alternatively, the peel
force is not less
than about 300 gmf/inch, and optionally is not less than about 400 gmflinch to
further
provide improved benefits. In other aspects, the peel force is not more than
about 1,200
gmf/inch. Alternatively, the peel force is not more than about 800 gmf/inch,
and optionally
is not more than about 600 gmf/inch to provide improved performance.
a o The engagement force between the selected first fastener component and its
appointed and cooperating fastener component may additionally provide a shear
force
value of not less than about 400 gmf per square inch of the area of engagement
between
the first and cooperating fastener components. Alternatively, the shear force
is not less
than about 1,000 gmf/in2, and optionally, is not less than about 1,700
gmf/in~. In further
as aspects, the shear force can be up to about 4,400 gmf/in~, or more.
Alternatively, the
shear force is not more than about 3,900 gmf/in2, and optionally is not more
than about
3,500 gmf/in2 to provide improved performance.
The peel force value can be determined in accordance with standard procedure
ASTM D-5170, approved Sept. 15, 1991 and published Nov. 1991; with the
following
3 o particulars. The test specimen is the fastener tab from the article being
assessed. The
test specimen length is the dimension aligned along the direction in which a
peel-away
force is typically applied to disengage and remove the fastener during the
ordinary use of
the article with which the fastener is employed. The specimen "width" lies
within the
general plane of the fastener and is perpendicular to the specimen length. The
roller
35 device weighs 4.5 pounds and includes a rubber coating around the roller
circumference.
A suitable roller is part number HR-100 available from Chemsultants
International, a
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business having a location in Mentor, Ohio. During the engagement of the
fastener
components, the roller is rolled over the test specimen through one cycle in
the direction
of the cross-wise "width" of the sample. In addition, the initial peel by hand
to "raise the
loops" is omitted. During testing, the fastener material held by the
stationary clamp can be
larger in area, as compared to the fastener material held in the moving clamp.
The initial
separation distance between the clamps of the tensile tester is 4 inch, and
the extension
speed of the tensile testing machine is 20 inch/min. The reported value of a
peel test
result is a "three-peak average" value employing MTS TESTWORKS software with a
peak
criteria of 2%. Additionally, the peel force value is normalized to be stated
in terms of
so force per unit length of the "width" dimension of the fastener component on
the test
specimen, such as grams per inch. The MTS TESTWORKS software is available from
MTS Systems Corporation, a business having offices in Eden Prairie, MN.
The shear force value can be determined in accordance with the standard
procedure ASTM D-5169, approved September 15, 1991 and published Nov. 1991
with
the following particulars. The test specimen is composed of the fastener tab
from the
article being assessed. The test specimen length and width typically
correspond to the
length and width employed to conduct the testing for peel force value.
Ordinarily, the test
specimen length is the dimension aligned along the direction in which a shear
force is
typically applied to the fastener during the ordinary use of the article with
which the
ao fastener is employed. The specimen "width" lies within the general plane of
the fastener
and is perpendicular to the specimen length. The roller device weighs 4.5
pounds and
includes a rubber coating around the roller. A suitable roller is part number
HR-100
available from Chemsultants International, a business having a location in
Mentor, Ohio.
During the engagement of the fastener components, the roller is rolled over
the test
specimen through five cycles in the direction of the cross-wise "width" of the
sample. In
addition, the initial peel by hand to "raise the loops" is omitted. During
testing, the fastener
material (e.g. the loop material) held by the stationary clamp can be larger
in area, as
compared to the fastener material (e.g. hook material) held in the moving
clamp. The
initial separation distance between the clamps of the tensile tester is 4
inch, and the
3 o extension speed of the tensile testing machine is 10 inch/min. The shear
force value is
normalized to be stated in terms of force per unit area of the test specimen,
such as
grams per inchz .
The particulars of the standard test procedures are intended to generate
fastening
conditions that can be more representative of consumer use conditions. When
preparing
the test specimen materials (e.g. hook and loop materials) to determine the
cooperating
peel and/or shear force values for the representatively shown configurations
of the
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invention, it should be noted that, the width dimension of the selected
specimen material
will correspond to the dimension of the fastener material which, in the actual
article, is
found to be aligned along the longitudinal direction 26 of the article.
Similarly, the length
dimension of the selected specimen material will correspond to the dimension
of the
s fastener material which, in the actual article, is found to be aligned along
the lateral
direction 24 of the article.
Desirably, the securing engagement between the first fastener component and
the
cooperating fastener components should be sufficient to prevent a
disengagement of the
components when subject to a tensile force of at least about 1,000 grams when
the
io tensile force is applied outwardly along the lateral direction, aligned
generally parallel with
the plane of the backsheet layer of the article.
Each of the fastener components and fastening elements in the various
constructions of the invention may be operably attached to its supporting
substrate by
employing any one or more of the attachment mechanisms employed to construct
and
15 hold together the various other components of the article of the invention.
The fastening
elements in the various fastening regions, may be integrally formed, such as
by molding,
co-extrusion or the like, along with their associated substrate layer. The
substrate layer
and its associated mechanical fastening elements may be formed from
substantially the
same polymer material, and there need not be a discrete step of attaching the
fastening
ao elements to an initially separate substrate layer. For example, the
individual hook
elements may be integrally formed simultaneously with a hook base-layer by
coextruding
the base layer and hook elements from substantially the same polymer material.
It should be readily appreciated that the strength of the attachment or other
interconnection between the substrate layer and the attached fastening
component should
25 be greater than the peak force required to remove the fastener tab. 36 from
its releasable
securement to the appointed landing member of the article.
Generally speaking, using wings or flaps of a personal care product as part of
a
selectively releasable, interengaging fastening system may present issues when
the
wings or flaps are made of a fairly flexible material. High levels of
flexibility allows for ease
30 of application and fastening and in some instances, ease of manufacturing.
However, too
much limpness, flexibility and/or floppiness in the wing or flap when used as
part of a
fastening system can lead to situations where the fastening system becomes
worn,
undesirably wrinkled, bunched and/or fails.
According to an embodiment of the present invention, configuring a flexible
first
35 fastener component to extend across at least the longitudinal direction or
dimension of a
relatively more flexible wing or flap helps alleviate twisting of the flaps
resulting in wear,
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wrinkling and fastener failure due to the fastener attachment system being too
flexible,
limp and/or floppy. Generally speaking, the first fastener component should be
slightly
more rigid (i.e., slightly less flexible) than the flexible material making up
the wing or flap.
One advantage of such a configuration is that the wing or flap incorporating
the first
fastener component is less likely to flutter and shake as it moves through
high speed
manufacturing and/or packaging processes.
The relatively flexibilities of the first fastener component and the flexible
material
making up the wing or flap can be determined using a conventional drape
stiffness test.
Such tests are well-known and can be readily carried out by persons of
ordinary skill. As
so one example, the relative flexibilities may be evaluated by determining the
drape stiffness
of a standard size sample (e.g., 10 cm x 10 cm, 15 cm x 15 cm or some similar
size) of
the material used to form the wing or flap and then determining the drape
stiffness of that
sample with the first fastener component attached substantially continuously
across at
least the longitudinally oriented direction of the sample (as it would be
oriented when
is attached to a product). While it is generally understood that a
conventional drape
stiffness test assesses resistance to flexure due to forces normal to the
plane of the
material, it is generally thought that for purposes of the present invention,
the relative
performance of a material in a conventional drape stiffness test serves as a
good
approximation to assess its ability to resist torsional forces of the type
encountered by
2o flaps or wings of a personal care product such as, for example, a sanitary
napkin during
typical use.
As used herein, the term "relatively more flexible" as it applies to the
relative
flexibilities of the first fastener component and the flexible portion of the
article (e.g., the
portion of the article making up the wing ~or flap) refers to a difference in
a conventional
25 drape stiffness test between the flexible portion (or material) and the
flexible portion (or
material) with the first fastener component attached of at least about 10%.
Desirably, the
difference will be at least about 25%. More desirably, the difference will be
greater than
50%. In some embodiments, it is contemplated that the difference may be
greater than
100%. In yet other embodiments, it is contemplated that the difference may be
greater
3 o than 250% and even greater than 500%.
Moreover, extending a flexible first fastener component across at feast the
longitudinal dimension or direction of a relatively more flexible wing or flap
avoids
problems associated with a small, discrete first fastener component centered
on the flap.
Referring now to FIG. 9, a small, discrete first fastener component 100
centered on a flap
s5 or wing 36 tends to develop a moment 110 centered on the fastener 100
(which serves as
an axis) when forces 120 orthogonal to the longitudinal direction or dimension
are applied
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through normal use. This typically leads to twisting and wrinkling of the
flaps and tends to
reduce fit-dependent performance of a personal care product incorporating such
a
fastening system. The twisting and bunching occurs because there is little or
no rigidity in
the wing to dampen the moment centered on the small, discrete fastener
component 100.
Referring now to FIG. 10, the same orthogonal forces 120 are present with the
present invention that utilizes a flexible first fastener component 70 that
extends
substantially across at least the longitudinal direction or dimension (shown
as "L") of a
relatively more flexible wing or flap 36. However, when the moment 110 forms
with the
"substantially continuous" first fastener component 70 in place, the moment is
dampened
so by a static force 130 in the opposite direction. This reduces the twisting
and wrinkling of
the flaps in absorbent personal care products when compared to flaps or wings
36 in
absorbent personal care products having the same construction but with the
"substantially
continuous" first fastener component 70 being replaced by a small, discrete
first fastener
component 100.
15 The term "substantially continuous" when used in connection with the first
fastener
component 70 should be understood as meaning a first fastener component that
extends
generally across at least a longitudinal direction or dimension "L" of a flap
or wing 36 as
shown in FIG. 10. Of course, it is contemplated that the first fastener may be
configured
to extend generally laterally (i.e., in the direction perpendicular to the
longitudinal direction
ao "L") across the wing or flap 36. It is also contemplated that the first
fastener component
may also extend both generally laterally and generally longitudinally across
the flap or
wing. For example, such a configuration could form a solid square patch, a
hollow square
patch, an "X" shape or other types of patterns or shapes. The term
"substantially
continuous" encompasses first fastener components that extend from edge to
edge on the
z5 flap or wing 36 as well as first fastener components that stop some
distance from the
edge of the flap or wing 36. Desirably, such first fastener components
generally extend
across at least about 50% of the longitudinal direction length of the wing.
Alternatively
and or additionally, the first fastener component may extend generally across
at least
about 50% of the lateral direction length of the wing or flap. More desirably,
such first
3 o fastener components generally extend across at least about 75% of the
longitudinal
and/or lateral direction length of the wing. Still more desirably, such first
fastener
components generally extend across at least about 90% of the longitudinal
and/or lateral
direction length of the wing. The first fastener components may be formed of
individual
segments of first fastener components that extend generally across from about
edge to
35 edge of the flap or wing and still be "substantially continuous". While
FIG. 10 illustrates
two wings 36 and only a single "substantially continuous" first fastener
component 70, it
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should be understood that first fastener components can be present on both
wings as
shown at, for example, FIG. 1A. It is also contemplated that a single large
wing or flap of
material may be used which is joined by the fastening system to a flexible
portion of an
absorbent personal care product.
According to an aspect of the invention, these features can be used to provide
a
selectively releasable, interengaging fastening system for an article having a
lengthwise
longitudinal direction, a lateral cross-direction, and a longitudinally
extending medial line, a
first article portion and a second article portion, the fastening system
including:
a first fastener component including at least a first flexible portion of an
article, the
to first fastener component extending substantially continuously across the
first flexible
portion of the article; and
a cooperating fastener component including at least a second flexible portion
of
an article and extending substantially continuously across the second flexible
portion of
the article such that the first and second portions of the article are capable
of being joined
is into an overlapping and interengaging configuration.
It has been discovered that when such a configuration is used and at least one
of
the first fastener component and cooperating fastener component has a rigidity
that is
greater than its respective flexible portion of the article, disengagement of
the first
fastener component and cooperating fastener component due to deformation of at
least
a o one of the flexible portions of the article is reduced. Desirably, the
first fastener
component and the cooperating fastener component extend substantially
continuously
across the longitudinal direction of their respective flexible portions of the
article.
Generally speaking, it is desirable for at least one of the first portion and
the
second portion of the article (to which the fastener components are attached)
have a
25 segment having a fixed end attached to an article body and a free end. More
desirably,
each of the first portion and the second portion of the article including a
segment having a
fixed end attached to an article body and a free end will form a respective
first flap portion
(or wing) and second flap portion (or wing). It is also contemplated that
single wing
configuration may be used.
3o In an aspect of the reduced disengagement feature of the present invention,
the
first fastener component extends substantially continuously across a first
respective flap
portion and the cooperating fastener component extends substantially
continuously across
a second respective flap portion. Desirably, each fastener component extends
across at
least about 50% of the longitudinal and/or lateral dimension or direction of
its respective
35 flap portion. More desirably, each fastener component generally extends
across at least
about 75% across the longitudinal and/or lateral dimension or direction of its
respective
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flap portion. Still more desirably, each fastener component generally extends
across at
least about 90% of the longitudinal and/or lateral dimension or direction of
its respective
flap portion. Alternatively, the first fastener component and cooperating
fastener
component may be present on and extend substantially continuously across each
respective flap portion and each may extend across at least about 50% of the
longitudinal
and/or lateral dimension or direction of its respective flap portion.
Desirably, these
components will extend across at least about 75% of the longitudinal and/or
lateral
dimensions of the flap portions and more desirably, will extend across at
least about 90%
of the longitudinal and/or lateral dimensions of the flap portions.
~o In an embodiment of the invention, the first fastener component may be
relatively
more rigid than its respective flexible portion of the article so that
disengagement of the
first fastener component and cooperating fastener component due to deformation
of at
least one of the flexible portions of the article is reduced. The relative
flexibility of the first
fastener component and the flexible portion of the article is discussed above.
At least one of the first and second flap portions may be formed partially
from,
completely from or may include portions of the cooperating fastener component.
The first fastener component includes an engagement section having a plurality
of
engagement members. The engagement section may be isotropic or substantially
non-
isotropic as described above. The cooperating fastener component may be a
nonwoven
a o loop material as described above.
Examples
The following examples are presented to provide a more detailed understanding
of the
invention, and are not intended to specifically limit the scope of the
invention.
Peel testing was conducted generally in accordance with ASTMD-5170 - 91 and
shear testing was conducted generally in accordance with ASTM D-5169 - 91.
Each test
utilized 10mm squares of HTH-851 hook material available from VELCRO hand-
mounted
on 2.Oosy PRESTO PUB loop material (See U.S. Application Serial No. 754,419).
The
3 o hook material was oriented in either MD or CD for the hook direction. The
pads were
worn by a mechanical walking model for 30 minutes at 72 strides/minute.
Equipment
Tensile Tester - Constant Rate of Extension tensile tester with MTS TestWorks
software.
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~ Walking Model (Size 5 torso)
~ Fruit of the Loom Women's Underwear (Size 5)
Sample Preparation
~ For Standard Peel and Shear testing:
- Wings are removed from the product cutting along the line of adhesive
juncture.
- Wings are then engaged used a mechanical roller to consistently engage wings
Mechanical roller available from Cheminstruments with a 2 Kg weight.
- Sample is then ready for Peel or Shear testing.
2o ~ For post wear testing of Peel and Shear:
- Underwear are placed on Walking Model.
- Pad is placed in underwear. Edge of front lobe always 1 cm in front of the
crotch
seam.
- Wings are then engaged and the underwear pulled onto the model.
i5 - Model is set to walk at 72 strides per minute for 30 minutes.
- Underwear are cut off the model and removed carefully to not impact hook
engagement.
- Wings are the removed from product and panty by cutting along the adhesive
juncture.
a o - Sample is the ready for post wear Peel and Shear testing.
Peel Test
~ Finger tab (area at end of wing beyond hook is placed in the upper jaw, cut
edge of
other wing is place in the lower jaw. Careful not to leave too much slack or
pull hook
a5 from loop engagement
~ Test is run at the following parameters:
- Crosshead speed - 20 in/min
- Gauge Length - 3 inches
- Load units - Grams
3 0 - Start Measure - 0.4 in .
- End Measure - 0.9 in
- Break Sensitive - 110%
- Slack Compensation - 50 grams
~ Response is the averaged gram of force over the length of the peel test.
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Shear Test
~ Cut edge of one wing is placed in the upper jaw and cut edge of opposing
wing is
placed in the lower jaw. Careful not to leave too much slack or pull hook from
loop
engagement.
s ~ Test is run at the following parameters:
- Crosshead speed - 20 in/min
- Gauge Length - 3 inches
- Load units - Grams
- Start Measure - 0.4 in
io - End .Measure - 0.9 in
- Break Sensitive - 110°l0
- Slack Compensation°- 50 grams
~ Response is the averaged gram of force over the length of the peel test.
15 Results of testing is reported in Table 1.
TABLE 1
MD- CD- MD- CD- MD- CD- MD- CD-
Peel Peel ShearShear Peel Peel Shear Shear
Std Std Std Std Post Post Post Post
Test Test Test Test Wear Wear Wear Wear
1.71 7.22 512.9603.8 74.7 32.96 437 674
4.27 14.02 237.9491 35.9212.2 635.8 649.6
0.1 0.94 201 785.2 42.5715.8 469.7 454.4
9.65 8.38 318 618.8 36.8623.16 1125.7551.4
6.9 1.88 202 591.9 206.026.26 1208.8485.6
6.53 10.37 267.9435 3 23.49 510.8 519.7
1.61 19.63 329.9473 34.7813.74 685.3 455.8
6.39 13.8 272.7912.7 72.9833.29 566.7 554.7
19.7229.26 550.8427.2 57.7525.35 780.9 581
1.46 9.38 341.4484.4 78.6716.29 934.5 383.1
7.42 4.24 403.7610.4 67.4743.95 382.3 466.6
3.75 17.86 237.4400.4 54.3729.39 523.9 434.5
9.69 20.62 246.4567.5 54.5 32.2 740.1 299.5
8.31 13.53 408.3525.6 66.31 619.1 438.7
8.07 5.74 424.2407.3 23.65 771.5 425.9
47.73
Avera 6.4 11.8 330.3555.6 63.6 25.2 692.8 491.6
a
Std 4.8 7.8 109.3142.7 42.7 9.2 242.9 98.9
Dev.
The data are summarized in Table 2. For both shear and peel values, the
orientation having the lowest weakest initial MD and CD peel and shear
strength values
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(i.e., the'illogical' orientation) engaged strongly during use. In contrast,
the orientation
having the greatest or strongest initial MD and CD peel and shear strength
values (i.e.,
the 'logical" orientation) either strengthens somewhat during wear or falls in
strength.
Also, for both the shear and peel value, the absolute after wear values are
higher for the
s 'illogical' orientation than for the 'logical'.
TABLE 2
before wear SD after wear SD ratio, before to after
illogical (MD) peel 6.4 4.8 64 43 10.0
logical (CD) peel 11.8 7.8 25 9 2.1
illogical (MD) shear 330 109 693 242 2.1
logical (CD) shear 556 143 491 99 0.9
to
These examples illustrate an embodiment of the mechanical fastening system of
the
present invention. More particularly, these examples show an embodiment in
which an
absorbent article such as, for example, a sanitary napkin has a fastening
system that
includes a pair of wings including selectively releasable, interengaging
fasteners such that
15 the wings are adapted to hold the sanitary napkin to an undergarment. The
wings are
adapted to increase engagement during use.
Having described the invention in rather full detail, it will be readily
apparent that
various changes and modifications can be made without departing from the
spirit of the
invention
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