Note: Descriptions are shown in the official language in which they were submitted.
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Disposable absorbent article having a folded landing member for
engaging with a hook-type fastening member
Field of the Invention
The invention relates to disposable absorbent articles comprising a
mechanical fastening system.
Such disposable absorbent articles are known from EP-A- 0 321 234.
Known mechanical fastening systems for use in disposable absorbent
articles comprise hook-type tape tabs in the back waist region which
mechanically engage with a landing member. The landing member is a
loop-type material which is located in a front waist region and which
entangles with the hooks of the tape tabs to form a closure having
resistance against peel forces and shear forces.
The known absorbent articles may comprise a landing member which is
positioned in a region of the backsheet to engage the hook-type tape
tabs when the article is placed in a roiled-up disposal configuration.
The loop-type materials used for the landing members of the known
mechanical fastening systems are relatively expensive materials.
Another drawback of the addition of separate patches or strips of loop-
type material to the backsheet, is an increase in the complexity of the
production process for making an absorbent article.
Furthermore, it is difficult to attach patches or strips of loop-type
material to the garment-facing side of an absorbent article in the front
waist region when the front waist region is elasticated, or is made of an
elastically extensible material, such that the material in the front waist
region is gathered. The patches of loop-type material, which are non-
elastic, may impair the elastic properties of the front waist region.
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It is therefore an object of an aspect of the present invention to provide
an absorbent article having a mechanical closing system which is of simple
construction and which is cost-effective.
It is a further object of an aspect of the present invention to provide an
absorbent article having a loop-type mechanical landing member which can
effectively and firmly adhere to or be a part of an elasticated waist region,
without impairing the elasticity thereof.
Summary of the Invention
The absorbent article according to the present invention comprises a
backsheet having a garment-facing side and a user-facing side, two
longitudinal sides, a front transverse edge, a front waist region located
along
the the front transverse edge, a back transverse edge end, and a back waist
region located along the back transverse edge. The mechanical fastening
system of the article comprises at least two hook-type fastening members
located in the back waist region. A landing member for mechanically engaging
with the hook-type fastening member is located in the front waist region. An
inner layer covers at least a part of the user-facing side of the backsheet in
the front waist region. The inner layer is doubled-over along a fold line in
the
front waist region such that the the inner layer is turned outwardly to the
garment-facing side and forms the landing member. The material of the inner
layer is adapted to mechanically engage with the hook-type fastening
members. Attachment means are provided for keeping the region of the front
waist edge of the inner layer against the backsheet in a doubled-over
configuration.
The inner layer may extend beyond the front transverse edge of the
backsheet and may be doubled-over onto the backsheet along the
backsheet's front transverse edge. Alternatively, the inner layer may be co-
extensive with the backsheet, both the backsheet and the inner layer being
doubled-over in the front waist region.
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By turning the inner layer that is located on the user-facing side of the
backsheet, outvvardly, a landing member is obtained in a simple
manner. No additional loop-type materials other than those normally
used in diaper manufacturing, need be attached to form the landing
member.
The landing member which is formed by the material of the inner layer
is flexible and can elastically contract and expand to conform to the
movements of the wearer. The conformability of the loop-type fastening
member according to the invention to the geometry of the wearer in the
front waist region, is especially advantageous when elastic elements are
located in the front waist region to provide a snug fit of the article
around the waist of the wearer.
The inner layer, which for instance comprises a fibrous non-woven
layer, may be the topsheet which covers the absorbent core or may be
a layer located between the topsheet and the backsheet to form a
barrier against leakage from the front transverse edge of the absorbent
core (a so-called waist shield layer). Alternatively, the inner layer may
be a layer which is located below the absorbent core and which is co-
extensive with the backsheet in the front waist region or may be a high
wet-strength tissue which envelops the core. By selecting the hook-
type fastening members to match the non-woven material that is
regularly employed as an inner layer, the hooks can mechanically
engage with this layer to fasten the absorbent article on a wearer.
For fibrous inner layers having relatively little surface irregularities,
relatively small and sharply pointed hooks will be required for the hook -
type material of t:he hook-type fastening members to be able to engage
with such a layer. For non-woven sheets or tissues which comprise a
relatively large number of protruding loops at their surface, the hooks of
the hook-type material may be of larger size and may be relatively
flexible to obtain mechanical attachment to such sheets or tissues.
Alternatively, the surface texture of the inner layers can be selected to
match a given type of hook-fastening material to achieve proper
fastening. The inner layer may be mechanically treated to impart the
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desired surface characteristics which ensure proper attachment to a pre-
determined type of hook material.
In one embodiment of an absorbent article according to the invention
an elastic element may be comprised on the inner layer for instance on the
topsheet along the front waist edge. The use of the elastic element in the
region of the landing member has as an advantage that the material of the
landing member is contracted to form gathers, which provide improved
attachment with the hook material of the hook-type fastening members.
The backsheet may be comprised of a non-woven material, a
thermoplastic film or a laminate of a non-woven material and a film. The
backsheet may be formed of an elastic material. There may be additional
layers located between the topsheet and the backsheet.
In another embodiment of an article according to the invention, at least
two cuts extend through the backsheet and the inner layer from the front waist
edge, in the direction of the back waist edge, wherein the part of the front
waist region of the backsheet which extends between the cuts is doubled-
over.
By doubling-over the backsheet along these cuts, a low-cut foldline of
the front waist region can be obtained which fits well below the belly of the
wearer in the so-called "low motion zone". Preferably, a number of cuts
extend radially from the front waist edge to an inwardly concave fold line,
such
that a number of backsheet-material sections are formed which are each
folded along the concave fold line. In this manner a shaped front transverse
edge and the landing member are formed simultaneously.
In one embodiment of an absorbent article according to the invention,
the longitudinal sides in the back waist region have a rounded section which
matches with the fold line in the front waist edge when the article is put on
a
wearer.
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The combination of the rounded sections of the longitudinal edges and the
low-cut front waist region provide room for comfortably fitting around the
belly
of the wearer.
Preferably, additional hook-type fastening elements are provided on
the front waist region to engage with the loop-type material of the back waist
region. The relatively low position of the additional hook-type fastening
elements on the doubled-over section of the front waist region, places them
below the rounded edges of the transverse sides and allows for proper
fastening of these additional hook-type elements without a need for increasing
the width of the backsheet material in the front waist region.
In accordance with one embodiment of the invention there is
provided an absorbent article which comprises:
a liquid pervious topsheet;
a backsheet joined to at least a portion of the topsheet having a garment-
facing side and a user-facing side, two longitudinal sides, a front transverse
edge, a front waist region located along the front transverse edge, a back
transverse edge, and a back waist region located along the back transverse
edge;
an absorbent core disposed between at least a portion of the topsheet and at
least a portion of the backsheet;
a mechanical fastening system comprising a hook-type fastening member
located in the back waist region and extending transversely beyond each
longitudinal side, and
a landing member for mechanically engaging with the hook-type fastening
member,
the landing member including at least a portion of the topsheet which is
doubled over the backsheet in at least a portion of the front waist region,
the
topsheet being adapted to mechanically engage with the hook-type fastening
members; and
attachment means for keeping the topsheet in a doubled-over configuration.
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Brief Description of the Drawings
The invention will be described in detail with reference to the accompanying
drawings. In the drawings:
Figure 1 shows a partially cut-away perspective view of a disposable diaper
comprising a landing member according to the invention,
Figure 2 shows a cross-sectional view through a hook-type fastening member
of figure 1 along a line of cross-section parallel to the back transverse
edge,
Figures 3-8 show cross-sectional views through the front waist region along a
line of cross-section parallel to the longitudinal centerline, of different
embodiments of landing members according to the invention,
Figures 9-11 show a perspective view of the garment-facing side of absorbent
articles having a number of cuts extending from the front transverse edge
towards a fold line,
Figure 12 shows a sectional plan view of a sheet having a number of
extensible parallel corrugations,
Figure 13 shows the garment-facing side of an absorbent article, wherein the
front waist region comprises parallel corrugations as shown in figure 13, and
Figure 14 shows a perspective view of a disposable absorbent article
according to the invention when put on a wearer.
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Detailed Description of the Invention
Mechanical closing systems of the present invention are useful and
beneficial when applied to disposable absorbent articles. As used herein, the
term "disposable absorbent article" refers to articles which absorb and
contain
body exudates and, more specifically, refers to articles which are placed
against or in proximity to the body of the wearer to absorb and contain the
various exudates discharged from the body and which are intended to be
discarded after a single use (i.e., they are not intended to be laundered or
otherwise restored or reused). A preferred embodiment of the disposable
absorbent article of the present invention is a diaper 20. As used herein, the
term "diaper" refers to a garment generally worn by infants or incontinent
persons that is drawn up between the legs and fastened about the waist of the
wearer. Examples of the kinds of diapers to which the present invention is
very readily adapted are shown in U.S. Patent Re. 26,1 51 issued to Duncan
et al. and in U.S. Patent 3,860,003 entitled "Contractible Side Portions for
Disposable Diaper" which issued to Kenneth B. Buell on January 14, 1975.
It will be apparent from the following description that the mechanical
fastening system illustrated and described herein may be applied to the body
portion of such diapers. On the other hand, it will be understood that the
invention is not limited to any specific diaper structure or configuration.
Referring to the drawings, it will be noted that Figure 1 is a partially cut-
away perspective view of the diaper 20 of the present invention prior to its
being placed on the diaper wearer by the diaper user. As can be seen in
Figure 1, a preferred diaper 20 comprises a body portion 22 and a fastening
system 24. A preferred body portion 22 comprises a liquid pervious topsheet
26, an absorbent core 28, a liquid impervious backsheet 30, and elastically
contractible leg cuffs 32 comprising a side flap 34 and one or more elastic
members 36. While the topsheet 26, the absorbent core 28, the backsheet 30,
the side flaps 34, and the elastic members 36 may be assembled in a variety
of well-known
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configurations, a preferred disposable diaper configuration is shown and
described generally in the above-referenced U.S. Patent 3,860,003
- which issued to Kenneth B. Buell on January 14, 1975.
Figure 1 shov~rs a preferred embodiment of the body portion 22 in
which the topsheet 26 and the backsheet 30 are coextensive and have
length and width dimensions generally larger than those of the
absorbent core 28. The topsheet 26 is superposed on the backsheet 30
thereby forminc,~ the periphery 38 of the body portion 22. The periphery
38 defines the outer perimeter or, in other words, the outer extend of
the body portion 22. The periphery 38 comprises longitudinal sides 40,
back transverse; edge 42, and fold line 49 along which the ~topsheet 26
and the backsh~eet 30 are doubled over to form landing member 64. The
body portion 2:2 has user-facing side 44 and garment-facing 46. In
general, the garment-facing side 46 of the diaper 20 extends from back
transverse edge 42 to fold line 49 of the diaper and from one
longitudinal side: 40 to the other longitudinal side 40 of the diaper and is
the surface farthest from the wearer during use of the diaper 20. The
garment-facing side of any layer comprised in the diaper 20 is the side
of the layer farthest from the wearer during use. When a backsheet 30
is used, it typically forms the larger part of the garment-facing side 46
of the body portion 22. The user-facing side 44 is that surface of the
diaper opposite the garment-facing side 46 and in the embodiment
shown is typic<~lly formed by the topsheet 26. In general, the user-
facing side 44 of the diaper 20 is that surface coextensive with the
garment-facing side 46 and which is for the greater part in contact with
the wearer when the diaper 20 is worn. For any layer comprised in the
diaper 20, the user-facing side is that side of the layer located closest
to the wearer during use.
The diaper 20 has first and second end regions 48 and 50, respectively,
extending from t:he back transverse edge 42, and the fold line 49 of the
diaper periphery 38 toward the transverse centerline of the diaper 20.
Both the first end region 48 and the second end region 50 extend a
distance of about one-half of the length of the diaper 20 such that the
end regions comprise each half of the diaper 20.
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Both the first end region 48 and the second end region 50 have panels
51. The panels 51 are those portions of the first end region 48 and the
second end region 50 which overlap when the diaper 20 is fastened
about the waist of the wearer. The extent to which the end regions
overlap and thus the extent to which the panels 51 are formed will
depend on the overall dimensions and shape of the diaper 20 and the
size of the wearer.
The absorbent core 28 of the body portion 22 may be any means which
is generally compressible, conformable, non-irritating to the wearer's
skin, and capable of absorbing and retaining liquids and certain body
exudates. The absorbent core 28 may be manufactured in a wide
variety of sizes and shapes (e.g., rectangular, hourglass, asymmetric,
etc.) and from a wide variety of liquid absorbent materials commonly
used in diapers and other disposable absorbent articles, such as
comminuted wood pulp which is generally referred to as the airfelt.
Examples of other suitable absorbent materials include creped cellulose
wadding, absorbent foams, absorbent sponges, superabsorbent
polymers, absorbent gelling materials, or any equivalent materials or
combination of materials. The total absorbent capacity of the absorbent
core 28 should, however, be compatible with the design exudate
loading in the intended use of the diaper 20. Further, the size and
absorbent capacity of the absorbent core 28 may varied to
accommodate wearers ranging from infants to adults.
While the absorbent core 28 may comprise a single layer of absorbent
material such as the configuration described in U.S. Patent 4,610,678
entitled "High-Density Absorbent Structure" which issued to Paul T.
Weisman and Steven A. Goldman on September 9, 1986 a preferred
embodiment of the absorbent core 28 is a dual-layered absorbent core
in a preferred configuration such as is generally described in U.S. Patent
4,673,402 entitled "Absorbent Article With Dual-Layered Cores" which
issued to Paul T. Weisman, Dawn I. Houghton and Dale A. Gellert on
June 16, 1987, having an asymmetric-shaped upper layer 52 and a
lower layer 54. The upper layer 52 preferably acts as a liquid
acquisition/distribution layer comprised primarily of hydrophilic fiber
material. The lower layer 54 acts as a liquid storage layer comprised of
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a mixture of hydrophilic fiber material and particles of an absorbent
gelling material lhydrogel material).
Both the upper layer 52 and the lower layer 54 preferably comprise an
absorbent layer encased in a tissue layer. It should be understood,
_ _ however, that the size, shape. configuration, and total absorbent
capacity of the upper layer 52 or the lower layer 54 may be varied to
accommodate wearer's ranging from infants through adults. Therefore,
the dimensions, shape, and configuration of both the upper layer 52
and the lower layer 54 may be varied (e.g., the upper layer or the lower
layer may have a varying caliper, a hydrophilic gradient, a rapid
acquisition zone or may contain absorbent gelling material).
The absorbent core 28 is superposed on the backsheet 30 and is
preferably associated thereto by a core attachment means 55 such as
those well known in the art, for example, pressure-sensitive adhesives,
hot melt adhesives or other adhesives; ultrasonic bonding; or
heat/pressure sealing. The absorbent core 28 may be secured to the
backsheet 30 by a uniform continuous layer of adhesive, a patterned
layer of adhesive, or any array of separate lines or spots of adhesive.
And adhesive which has been found to be satisfactory is preferably a
hot-melt adhesive such as manufactured by Eastman Chemical Products
Company of Kingsport, Tennessee and marketed under the tradename
of Eastobond A-3* or by Century Adhesives, Inc., of Columbus, Ohio
and marketed under the tradename Century 5227* The core attachment
means 55 preferably comprise an open pattern network of filaments of
adhesive as is shown in U.S. Patent 4,573,986 entitled "Disposable
Waste-Containment Garment" which issued to James A. Minetola and
David R. Tucker on March 4, 1986.
The backsheet 30 is impervious to liquids and is preferably
manufactured from a thin plastic film, although other flexible liquid
impervious materials may also be used. The backsheet 30 prevents the
exudates absorbed and contained in the absorbent core 28 from soiling
articles which contact the diaper 20 such as bedsheets and
undergarments. Preferably, the backsheet 30 is a polyethylene film
having a thickness of from 0.012 mm 10.5 mil> to 0.051 mm 12.0 milsl,
* = Trade-mark
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although other flexible, liquid impervious materials may be used. As
used herein, the .term "flexible" refers to materials which are compliant
and which will readily conform to the general shape and contours of the
human body.
_A suitable polyethylene film is manufactured by Monsanto Chemical
Corporation and marketed in the trade as Filrn No. 8020. The backsheet
30 is preferably embossed and/or matte finished to provide a more
clothlike appearance. Further, the backsheet 30 may permit vapors to
escape from the absorbent core 28 while still preventing exudates from
passing through the backsheet 30.
The size of the backsheet 30 is dictated by the size of the absorbent
core 28 and the exact diaper design selected. In a preferred
embodiment, the backsheet 30 has a modified hourglass shape
extending beyond the absorbent core a minimum distance of at least
1.3 cm to 2.5 cm (0.5 to 1.0 inch) around the entire diaper periphery
38.
The topsheet 26 of the body portion 22 of the present invention is
compliant, soft feeling, and non-irritating to the wearer's skin. Further,
the topsheet 26 is liquid pervious permitting liquids to readily penetrate
through its thickness. A suitable topsheet 26 may be manufactured
from a wide range of materials such as porous foams, reticulated
foams, apertured films, natural fibers (e.g. wood or cotton fibers),
synthetic fibers (e.g., polyester or polypropylene fibers) or from a
combination of natural and synthetic fibers. Preferably, it is made of a
hydrophobic material to isolate the wearer's skin from liquids retained in
the absorbent core 28.
A particularly preferred topsheet 26 comprises staple length
polypropylene fibers having a denier of about 1.5, such as Hercules
Type 151 polypropylene fibers marketed by Hercules, Inc. of
Wilmington, Delaware. As used herein, the term "staple length fibers"
refer to those fibers, having a length of at least 15.9 mm (0.625
inches 1.
* = Trade-mark
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There are a number of manufacturing techniques which may be used to
manufacture the topsheet 26. For example, the topsheet 26 may be
woven, non-woven, spunbonded, carded, hydroformed or the like. A
preferred topslheet 26 is carded and thermally bonded by means well-
known to those skilled in the fabric art. Preferably, the topsheet 26 has
a basis weight from 15 to about 30 grams per square meter, a minimum
dry tensile strength of at least 400 grams per centimeter in the machine
direction and a~ wet tensile strength of at least 55 grams per centimeter
in the cross-m<~chine direction.
The topsheet :Z6 and the backsheet 30 are associated together in any
suitable manner as is well known in the diaper manufacturing art. As
used herein, the term "associated" encompasses configurations
whereby the i:opsheet 26 is directly joined to the backsheet 30 by
affixing the topsheet 26 directly to the backsheet 30, and
configurations whereby the topsheet 26 is indirectly joined to the
backsheet 30 by affixing the topsheet 26 to intermediate members
which in turn are affixed to the backsheet 30. in a preferred
embodiment, tlhe topsheet 26 and the backsheet 30 are joined directly
to each other in the diaper periphery 38 by a flap attachment means 56
such as an adhesive or any other attachment means as is known in the
art. In general, the core attachment means 55 that affixes the
absorbent core 28 to the backsheet 30 is the same means as the flap
attachment means 56 that affixes the topsheet 26 to the backsheet 30.
Thus, for example, a uniform continuous layer of adhesive, a patterned
layer of adhesive, an array of separate lines or spots of adhesive, or a
network of adhesive filaments such as shown in the above-referenced
U.S. Patent 4,Fi73,986 may be used.
Elastically contractible leg cuffs 32 are disposed adjacent the periphery
38 of the body portion 22, preferably along each longitudinal edge 40,
so that the leg cuffs 32 tend to draw and hold the diaper 20 against the
legs of the wearer. While the leg cuffs 32 may comprise any of several
means as are well known in the diaper art, a particularly preferred leg
cuff construction comprises a side flap 34 and one or more elastic
members 36, as is described in detail in the hereinbefore referenced
U.S. Patent 3,8.60,003. In addition, a method and apparatus suitable for
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manufacturing a disposable diaper having elastically contractible leg
cuffs are described in U.S. Patent 4,081,301 entitled "Method and
Apparatus For Continuously Attaching Discrete, Stretched Elastic
Strands to Predetermined Isolated Portions of Disposable Absorbent
Articles" which issued to Kenneth B. Buell on March 28, 1978.
In a preferred embodiment, the elastically contractible leg cuff 32
comprises a side flap 34 and an elastic member 36 comprising an
elastic thread.
The diaper 20 is provided with a fastening system 24 for forming a side
closure. Thus, the diaper 20 is fitted to the wearer and the first end
region 48 and the second end region 50 are maintained in an
overlapping configuration when the diaper 20 is worn.
In a preferred embodiment of the present invention as shown in Figure
1, the fastening system 24 comprises fastening members 58, preferably
comprising a tape tab 60 and a hook-type fastening element 62,
disposed adjacent each longitudinal side 40 of the body portion 22 in
the back waist region 98 of the first end region 48; a landing member
64, engageable with the hook-type fastening element 62, disposed on
the outside surface 46 of the body portion 22 in the front waist region
94. The landing member 64 is formed by folding the topsheet 26 and
the backsheet 30 around fold line 49, and attaching the doubled-over
front waist region of the backsheet to the main backsheet portion with
attachment means 90. Additional fastening/disposal means 68 may be
positioned on the tape tab 60, for allowing the diaper 20 to be secured
in a disposal configuration so as to provide convenient disposal of the
diaper 20.
Each fastening member 58 is intended to provide a mechanical
fastening means for engaging the landing member 64 so as to provide a -
secure side closure for the diaper 20.
The fastening members 58 comprises combination of a hook-type
fastening element and adhesive attachment means positioned on the
body portion 22 of the diaper 20. The hook-type fastening element 62
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of each fastening member 58 is joined to the body portion and
preferably covers an area 25 mm wide (i.e., generally perpendicular to
the longitudinal centerline 29) by 62.5 mm long (i.e., generally parallel
to the longitudinal centerline 29) at the panels 51 of the body portion
- 22. An exemplary embodiment of a hook-type fastening member 62 is
described in U.S. Patent 4,699,622 entitled "Disposable Diaper Having
an Improved Side Closure" issued to John W. Toussant and Margaret
H. Hasse on October 13, 1987.
As shown in Figures 1 and 2, the fastening member 58 most preferably
comprises a tape tab 60. Any of the well known configurations and
constructions of a tape tab may be used. A preferred tape tab 60 is a
Y-shaped tape tab as described in detail in GB-A-1458566. Alternatively
preferred tape tabs are described in detail in co-pending European
Patent Application No. 87300450.1.
A particularly preferred tape tab 60 is illustrated in Figure 2 and has a
fastening surface 70 and a backing surface 72. The fastening surface
70 is that surface of the tape tab 60 designed to engage the landing
member 64 of the present invention. Thus, the fastening surface 70 of
the tape tab 6C1 will generally correspond to the garment-facing side 44
of the body portion 22. The backing surface 72 is that surface opposite
of the fastening surface 70 and generally corresponds to the outside
surface 46 of the body portion 22. The backing surface 72 is thus
generally exposed during wear of the diaper 20.
The preferred tape tab 60 illustrated in Figure 2 is one which is
anchored to both the user-facing side 44 and the garment-facing side
46 of the body portion 22 to create a manufacturer's end (i.e., that
attachment of the tape tab 60 to the diaper 20 made during
manufacture of the diaper 20). The tape tab 60 has another element
which forms the user's end i.e., that joint made by the person in
securing the di<~per to the wearer). Thus, the preferred tape tab 60 of
the present invention has at least three elements, a first fixed portion
74, a second fixed portion 76, and a connective portion 78. The first
fixed portion 74. is that portion of the tape tab 60 which is attached to
the user-facing side 44 of the body portion 22. The second fixed
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portion 76 is that portion of the tape tab 60 which is attached to the
garment-facing side 46 of the body portion 22. The first fixed portion
74 and the second fixed portion 76 thus form the manufacturer's end
of the tape tab 60. The connective portion 78 is that portion of the tape
tab 60 which is attached to another portion of the diaper 20, generally
the landing member 64 by the user when securing the diaper 20 on the
wearer. The connective portion 78 thus forms the user's end.
Additionally, the outer surface of the second fixed portion 76 and the
outer surface of the connective portion 78 form the backing surface 72
of the tape tab 60 while the inner surface of the first fixed portion 74
and the inner surface of the connective portion 78 form the fastening
surface 70 of the tape tab 60.
The preferred Y-shaped tape tab 60 of the present invention can be
constructed in several ways. The first fixed portion 74, the second
fixed portion 76, and the connective portion 78 can each be separate
tapes which meet and are joined adjacent the longitudinal edge 40 of
the body portion 22 in an area of joinder. A more practical structure for
the tape tab 60 is one in which the connective portion 78 and either the
first fixed portion 74 or the second fixed portion 76 are a unitary strip
of tape material. If the connective portion 78 is unitary with the second
fixed portion 76 as shown in Figure 2, then the first fixed portion 74 is
a separate element which is attached to the combined connective
portion and the second fixed portion adjacent to the longitudinal side 40
of the body portion 22.
Figure 2 also shows tab attachment means for securing the tape tab 60
to the body portion 22. These tab attachment means are any of those
attachment means which provide an adequate bond, and preferably are
any of the pressure-sensitive adhesives well-known to those of ordinary
skill in the adhesive art. The outer surface of the first fixed portion 74 is
affixed to the user-facing side 44 of the body portion 22 by a first tab
attachment means 80. The inner surface of the second fixed portion 76 _
is affixed to the garment-facing side 46 of the body portion 22 by a
second tab attachment means 82. The connective portion is provided
with a first fastening element 62 joined to it preferably by the second
tab attachment means 82 (alternatively, a third tab attachment means if
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the connective portion 78 is a separate element from the seCOnd fixed
portion 76), although an adhesive attachment means may be placed on
the first fastening element 62 separately and the combined material
joined to the connective portion 78.
Preferred materials for the tape tabs 60 comprises a tape material such
as tape code numbers XPF 14.43.0, Y-9376, or Y-9030 available from
The Minnesota Mining and Manufacturing Company, St. Paul,
Minnesota. The tape material in the embodiments are preferably a
polyethylene film having a tab attachment means tailored to bond to the
polyethylene positioned on the tape material. The tape tab attachment
means may c~~mprise any of those adhesives which provide an
adequate bond with other portions of the diaper, and is preferably any
of the pressure-sensitive adhesives well-known to those of ordinary skill
in the art. Preferred tab attachment means is a pressure-sensitive
adhesive such as code number XPF 1.42.34 available from The
Minnesota Mining an Manufacturing Company, St. Paul, Minnesota.
As shown in Figure 2, the tape tab 60 may also have a grip tab 83 at
the distal edge 71 in the connective portion 78. The grip tab 83 may be
formed by folding over a small margin of the distal edge 71 of the
connective portion 78 and attaching it to itself. This forms an end on
the connective portion 78 which is easier to grasp by the diaper user
when the diaper 20 is to be fitted and attached to the wearer. The grip
tab 83 is most t~eneficial when used when the connective portion 78 is
superposed on the first fixed portion 74.
The hook-type fastening element 62 of the present invention comprises
a hook fastening material 84. As used herein, the term "hook fastening
material" is used to designate a material having engaging elements 86.
. It should also be understood that the use of the term "hook" should be
non-limiting in the sense that the engaging elements 86 may comprise
any shapes as are known in the art so long as they are adapted to
engage a complementary second fastening element 66. As shown, the
hook fastening material 84 preferably comprises a base 88 having a
first surface and a second surface and a plurality of engaging elements
86 extending from the first surface of the base 88. Each of the
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16
engaging elements 86 are shown to comprise a stem supported at one
end on the first surface of the base and an enlarged head positioned at
the end of the stem opposite of the base.
The hook fastening material 84 of the present invention is intended to
engage fibrous elements of fibrous material on the user-facing side 44
of the backsheet, which fibrous material may for instance be formed by
the topsheet 26 or by a waist shield 91. Thus, the hook fastening
material 84 may be manufactured from a wide range of materials.
Suitable materials include nylon, polyester, polypropylene, or any
combination of these materials. A suitable hook fastening material 84
comprises a number of shaped engaging elements 86 projecting from a
woven backing such as the commercially available material designated
"Scotchmate"*brand No. FJ3402 available from Minnesota Mining and
Manufacturing Company, St. Paul, Minnesota. Alternatively, the
engaging elements may have any shape such as hooks. "T's" or any
other shape as are well known in the art.
Other suitable hook-type materials for use in the present invention are
far instance extruded hooks available under the reference MC5 from the
Minnesota Mining and Manufacturing Company, ST. Paul, Minnesota or
printed hooks available from the same company under references
CS200 and MC6. Other suitable hook-type materials are available under
reference 942 or 960E from Aplix, Inc.. P.O. Box 7505, Charlotte, NC
28241.
The landing member 64 comprises a loop-type material such as for
instance the fibrous topsheet material. As used herein, the term "loop-
type" material is intended to mean any fibrous material which can
mechanically engage with the hook-type material of the fastening
members 58 to maintain the diaper 20 affixed around the waist of a
wearer. Suitable loop-type material is described in US-A-5,326,612
IGoulait).
* = Trade-mark
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17
. Other suitable loop-type materials for use in the present invention may
comprise woven materials such as brushed loops available from
- Texmaille S.A., Rue Pasteur, 02610 Moy de L'aisne, France; double
knit loops available from Tissages de Quintenas S.A., Parc d°activit~s
de marenton, B.P.158-07104 Annonay, France; and Lineriess loops
available under reference LLL from the Minnesota Mining and
Manufacturing Company.
Again other suitable loop-type materials are formed by non-woven
materials.
In general, the materials of the hook-type fastening members 58 and
the loop-type landing member 64 should be selected such that the peel
force of a 30 n.~m wide patch of hook-type material is between 3 and
20 N, preferably about 7-8 N and the shear force of a patch of hook-
type material of dimensions of 30 x 13 mm is between 10 and 100 N,
preferably abouvt 50 N.
The tests for measuring the peel forces and the shear forces exerted by
the hook-type fastening members 58 on the loop type landing member
64 are described below.
I. 135o-Peelforce Test
This method describes the procedure for measuring the peel force, in
grams, of the combined hook-type fastening member and loop-type
landing member., The materials under test are mounted on a steel plate-
sled assembly and are separated at a constant peel angle of 135~.
During the test the temperature is maintained at 73 ~ 2o F. The
relative humidity is controlled at 50 ~ 2 %.
A patch of loop=type material measuring 2 in. x 4 in. is placed on a 2 in.
x 8 in. x 0.06 in. steel plate with a double-sided tape of the same
dimensions as the patch of loop-type material.
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A patch of hook-type material measuring 1 in. x 0.7'' in. is attached to
a tape tab of similar kind as the tape tab 60 shown in figure 1, adjacent
the area of the grip tab 83, further referred to in this test method as the
leading edge of the tape tab 60. No actual grip tab needs be present at
the leading edge of the tape tab 60 during testing. If the hooks of the
hook-type material are angled with respect to the tape tab, the hooks
are oriented to be inclined towards the leading edge.
The hook-type material is placed on the loop- type landing member.
Subsequently, a rubber-coated steel roller of diameter of 3.25 in., a
width of 1.75 in. and a weight of 4.5 Ibs is rolled back and forth in the
length direction of the tape tab 60 twice (a total of four passes).
The steel plate with the attached hook-type and loop-type materials is
mounted into an INSTRON*test apparatus, Model 4201, which is sat to
have.a cross-head speed of 12 in./minute and a Load Cell of 1 kg.
The steel plate is slidably mounted in a sled which is carried by the
*
lower jaw of the INSTRON apparatus.
The leading edge of the tape tab 60 is placed in the upper jaw of the
INSTRON*apparatus .
The upper cross head is set in motion to pull the leading edge of the
tape tab 60 off the loop-type landing member at an angle of 135o with
respect to the loop-type landing member. The steel test plate on which
the loop-type landing member is mounted, is moved in the sled
consecutively with the cross head relative to the lower jaw to maintain
a constant angle of 135o during the full cycle of peeling off the tape
tab.
The peak force, in grams, is recorded for at least four samples and is
averaged.
II. 1800 Shear Test
* = Trade-mark
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This method describes the procedure for measuring the shear force, in
grams, of the combined hook-type fastening member and loop-type
landing member. The materials under test are mounted on a steel plate
and are separated at a constant peel-angle of 1800.
During the test the temperature is maintained at 73 ~ 20 F. The
relative humidity is controlled at 50 ~ 2 %.
A patch of loop-type material measuring 2 in. x 5 in. is placed on a 2
in. x 5 in. x 0.06 in. steel plate with a double-sided tape of the same
dimensions as the patch of loop-type material.
A patch of hook-type material measuring 1 in. x 0.75 in. is attached to
a tape tab of similar kind as the tape tab 60 shown in figure 1, adjacent
the area of the grip tab 83, further referred to in this test method as the
leading edge of the tape tab 60. No actual grip tab needs be present at
the leading edge of the tape tab 60 during testing. If the hooks of the
hook-type material are angled with respect to the tape tab, the hooks
are oriented to be inclined away from the leading edge.
The hook-type material is placed on the loop-type landing member.
Subsequently, a rubber-coated steel roller of diameter of 3.25 in., a
width of 1.75 in. and a weight of 4.5 Ibs is rolled back and forth in the
' length direction of the tape tab 60 twice (a total of four passes).
The steel plate with the attached hook-type and loop-type materials is
mounted horizontally into the lower jaw of an INSTRON test apparatus,
Model 4201, which is set to have a cross-head speed of 12 in./minute,
a Load Ceil of 10.0 kg and a gage length of 2 in.
The leading edge of the tape tab 60 is placed in the upper jaw of the
INSTRON'~pparatus .
The upper cross head is sat in motion to pull the leading edge of the
tape tab 60 off the loop-type landing member at an angle of 185° with
%~ = Trade-mark
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respect to the loop-type landing member. When the maximum.pull force
has been reached, the crosshead is returned to the pre-set gage length.
The peak force, in grams, is recorded for at least four samples and is
averaged.
Figure 3 shows an embodiment wherein the landing member 64
comprises the topsheet 26, the backsheet 30 and an elastic element 99
comprised between the topsheet and the backsheet. The doubled-over
combination of the topsheet, backsheet and elastic member, forms an
elastically extendable landing member 64 comprising a number of
gathers. The front waist region 94 of the backsheet 30 is attached to
the main body of the backsheet by adhesive 90. Instead of adhesive
attachment means 90, heat bonding, utrasonic bonding or pressure
bonding may be used to maintain the front transverse edge 42' of the
backsheet 30 in an inwardly folded position. The topsheet 26, the
elastic element 99 and the backsheet 30 are all connected by adhesive
connections 101,105,106,107, and 108, which may be formed by
spiral glue patterns.
Preferably, the elastic element 99 provides a contractive force of
between 20 and 250 g per 2.54 cm of the elastic element's width, at
an elongation of 2.54 cm. The most preferred contractive force is about
150 g per 2.54 cm width at 2.54 cm elongation.
In the embodiment of figure 4, the elastic member 99 is, before
doubling over along fold line 49, located on the user-facing side 44 of
the topsheet 26. The elastic member 99 may in this case be comprised
of a strechable non-woven material, which is adapted to engage with
the hook-type fastening members. Alternatively, as shown in figure 4,
the elastic member 99 may comprise a laminate of an elastomeric film
96 and a non-woven layer 97 attached to the elastomeric film. In this
case the elastomeric film 96 of the elastic laminate is attached to the
tophseet 26, the non-woven layer 97 of the elastic laminate being,
before doubling over along fold line 49, located on the user-facing side
44 of the topsheet. When the front waist section 94 is doubled-over
along fold line 49, the non-woven layer 97 of the elastic laminate will
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21
be located on the garment-facing side 46 of the backsheet 30 facing
outwardly and forming the landing member 64.
In the embodii.~nent of figure 5, the elastic element 99 comprises a
segment 110 which is unattached to the underlying topsheet layer.
Upon doubting-over of the topsheet 26 and the backsheet 30 along the
fold line 49 in the front waist region 94, the unattached segment 110
of the elastic member 99 protrudes outwardly and forms a flexible and
elastic waist pa~nei, which will contact the stomach of the wearer during
use.
In the embodiment of figure 6, the inner layer that forms the landing
member 64, comprises a layer 91 which underlies the core 28 and
which is co-extensive with the user-facing side 44 of the backsheet 30.
"~ inner layer 91 may be a core-reinforcement layer or may be the
lower layer of an envelope layer which enwraps the core 28.
In the embodirnent of figure 7, a fibrous waist shield 92 is located
between the core 28 and the topsheet 26 along the front transverse
region 94. The waist shield layer 92 extends beyond the front
transverse edge of the topsheet 26 and the backsheet 30 and is
attached to the: backsheet in a doubled-over position by attachment
means 90.
In the embodiment of figure 8, the topsheet 26 extends beyond the
front transverse: edge 42' of the backsheet, and is doubled over along
the front transverse edge 42' to form the landing member. The folding
line 49 and the front transverse edge 42' of the backsheet 30 coincide
in this embodiment.
In the embodiment of figure 9, a number of cuts 111,112,113 extend
through the backsheet 30 and the inner layer 91 from the front
transverse edge 42' towards an inwardly concave fold line 49. By the
cuts 111,112,'113, separate sections 114,115,116 and 117 are
formed, each section extending between two adjacent cuts. The
backsheet 30 and inner layer 91 of each section are folded along the
fold line 49 to obtain a low-cut front waist region 94. In the
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embodiment of figure 10, the landing member 64 is formed by the
doubled-over part of the front waist region 94 extending between two
curved cuts 111,112. In the embodiment of figure 11, a number of cuts -
111,112,113 extends in a direction generally parallel to the longitudinal
sides 40. The fold line 49 for each section 114,115,116 is generally
parallel to the transverse edges 42,42'. The folded-over sections
114,115,116 result in a stepped front transverse edge. The stepped
edge of the front waist region 94 may be cut along the contour 120 to
obtain an inwardly concave waist region.
Figure 12 shows an enlarged plan view of a landing member 64
comprising a number of parallel corrugations 103, i 04. The corrugations
impart extensibility to the landing member 64, and cause the fibers of
the landing member 64 to project outwardly and improve the
mechanical fastening of the hook-type fastening members 58 thereto.
The pattern of figure 12 may for instance be provided after doubling
over of the topsheet onto the backsheet as shown in figure 13 and
subsequently passing the front waist 94 region between two
corrugated, intermeshing rolls, as described in US-A- 5,196,000 and
US-A-5, 236,430.
Figure 14 shows a disposable absorbent article 20 when put on a
wearer, the article comprising rounded sections 121 of the longitudinal
sides 40. The rounded sections 121 match with the region of the fold
line 49 and form a rounded contour. Additional patches of hook-type
material 122 are located on the doubled-over landing member 64 to
connect to the user-facing side (topsheet material) in the back waist
region 98. The presence of the additional patches of hook-type material
122 helps to maintain the front and back end regions 48,50 of the
article 20 in a properly overlapping relationship on the wearer.
WHAT IS CLAIMED IS:
