Note: Descriptions are shown in the official language in which they were submitted.
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PATENT
AN ABSORBENT ARTICIE HAVING A CUP-SHA~PED CONFIGU~ATION
This application is a continuation-in-part of U.S.S.N. 843,332
filed March 24, 1986 which in turn is a continuation application of
U.S.S.N. 581,945 filed February 21, 198~, now abandoned.
Field of the Invention
This invention relates to an absorbent article, especially to
sani-tary napkins and pantiliners, wherein the article has a cup-
shaped configuration which prevents side leakage and better conforms
to the shape of the human body.
Backqround of the Invention
Most absorbent articles, especially feminine pads, sanitary
napkins, pantiliners, incontinen-t garments and the like, which are
manufactured today are long and narrow and usually are relatively
flat. These flat products are designed to be worn tightly against
the curved torso of a human body and are generally held in place by
an undergarment. Such flat products have a tendency to buckle or
wrinkle as they conform to the body profile as the undergarment is
pulled up and secured around the wearer's torso. These buckles and
wrinkles can facilitate side leakage of body fluids which have been
deposited onto the cover of the product. Side leakage is probably
the number one reason way these types of absorbent articles fail.
In most instances, fluid leakage results not from saturation of
the absorbent material but rather from fluid running off of the cover
material. It is common for body fluid deposited onto the cover to
form a pool before it penetrates down through the fluid permeable
cover and into the absorbent. This pooling effect is due to a
variety of factors, such as the size openings in the cover, the fluid
permeability of the cover material, the amount of fluid discharged
onto the cover in a short period of time, as well as the composition
of the fluid itself. Body fluid may contain menses, blood, urine and
other aqueous fluids. Menses, in particular, is a complex fluid
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which may be highly viscous and normally contains a mucoidal
fraction, as well as cellular debris, amongst other aqueous
components. Both the mucoidal fraction and the cellular debris tend
to collect at the surface capillaries of the cover material and block
the passage of the more aqueous components into the absorbent.
Side leakage occurs when the deposited body fluid pools on the
cover material and is allowed to spread along the surface of the
cover beFore being absorbed into the absorbent. Body movement and
wrinkles in the product commonly assist the fluid in flowing
outwardly. Since the side edges are closer to the fluid discharge
area then are the distal ends, the product tends to leak at the side
edges rather than at the ends. Such side leakage usually occurs well
before the bulk of the absorbent has been wetted or insulted.
Attempts have been made to increase comfort of feminine care
products as well as to insure greater surface contact in the perineal
area by providing products having an hourglass shape. U.S. patents
3,805,790 and 4,490,147 teach two different hourglass shapes. An
hourglass shaped product conforms better to the shape of the human
thighs, especially adjacent to the perineal area. U.S. ~atent
4,324,246 shows an absorbent article with a seam formed inward of the
outer peripheral edge along with a narrow central portion to provide
a better fit with the body. A better fit means less distortion
during body movement and should create a better interface between the
perineal area and the cover.
Yarious attempts at producing a feminine product with side flaps
or walls have also been tried. Examples include EPA 0,091,412 which
teaches a sanitary napkin which utilizes a thicker and wider
absorbent in the central portion but which also uses elastic to form
upstanding walls. U.S. patents 4,579,556 and 4,66~,230 teach arcuate
shaped products having a rectangular absorbent and elastic secured to
either a portion of or along the entire length of the longitudinal
edges. The elastic forms upstanding walls which assist in preventing
side leakage oF body fluid. Two additional U.S. patents ~,701,177
and 4,770,657 teach threP-dimensional shaped feminine pads having
elasticized edges and an overall concave shape to better fit the
female body. These last two patents are assigned to the p~esent
c~
assignee and were filed after the date of the parent case to which
this application depends.
Diapers represent another type of absorbent article which have
experimented with leg elastics. Several U.S. patents which teach the
use of elastic to form a body sPal include: 3,860,003; 4 ? 324,245;
4,325,528; 4,337,771; 4,352,355 and 4,496,360. It should be noted
that diapers are different from feminine care products in that they
do not require the same intimate contact between the wearer's body
and the product itself. However, the use of elastic to form side
seals is relevant to both types of products.
Now an absorbent article has been developed which has a cup-
shaped configuration so as to prevent side leakage of body fluids and
better conform to the curve shape of a human torso.
Summarv of the Inven_ion
8riefly, this invention relates to an absorbent article, such as
a feminine pad, sanitary napkin, pantiliner, light incontinent
device, etc., which has a cup-shaped configuration. The absorbent
article is designed to form a better fit with the human torso and the
cup-shaped configuration includes upstanding side walls which prevent
side leakage of body fluids deposited onto the cover of the product.
The absorbent article includes an absorbent having a first surface
which faces the body of a user and a second surface aligned opposite
to the first surface. The absorbent has a pair of longitudinally
extending arcuate sides which are arranged to be close to each other
at a point approximate a central portion of the absorbent. A fluid
permeable cover is positioned adjacent to at least the first surface
of the absorbent and a fluid-impermeable baffle if positioned
adjacent to at least the second surface of the absorbent. The cover
and baffle are sealed together to enclose the absorbent. The seal is
formed inward of the outer peripheral edge of the article. The
article further includes a pair of elastic members affixed between
the cover and the baffle outward of the seal and aligned adjacent to
the central portion of the absorbent. The elastic members cause the
absorbent article to acquire a cup-shaped configuration which
corresponds to the perineal area of a user. The elastic members also
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bias a portion of the cover and baffle upward and outward to form
walls adjacent to the central portion of the article which prevent
side leakage of body fluids.
The general object of this invention is to provide an absorbent
article having a cup-shaped configuration which better conforms to
the curved shape of a human torso. A more specific object of this
invention is to provide an absorbent article with upstanding side
walls which prevent side leakage of body fluids deposited onto the
cover of the product.
Another object of this invention is to provide a feminine care
product with an hourglass shaped absorbent so that it is less prone
to distortion during body movement.
A Further object of this invention is to provide a sanltary
napkin with an arcuate shape along its longitudinal axis to better
fit the female body.
Still another object of this invention is to provide a feminine
protection device which is relatively easy to manufacture and low in
cost.
Still further, an object of this invention is to provide a
sanitary napkin, pantiliner or incontinent garment with a curved
profile which better conforms to the shape of a human body.
Other objects and advantages of the present invention will
become more apparent to those s~killed in the art in view of the
following description and the accompanying drawings.
Brief DescriDtion of the Drawinqs
Fig. 1 is a plan view of an absorbent article having an
hourglass shape with a pair of longitudinally extending arcuate sides
which are arranged to be close to each other at a point approximate a
central portion of the absorbent.
Fig. 2 is a cross-sectional view of the absorbent article shown
in Fig. 1 taken along line 2--2.
Fig. 3 is a side perspective view of the absorbent article shown
in Fig. 1 partially turned toward the viewer and depicting the
overall cup-shaped configuration.
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Fig. 4 is a side perspective view o~ the absorbent article shown
in Fig. 1 with one end of the article resting on a horizontal plane
to depict an angle alpha (~) representing the amount of curvature in
the cup-shaped article.
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Detailed Description of the Pr_ erred Emb~o_iment
Referring to Figs. 1 and 2, an absorbent article 10 is shown in
the shape of a feminine pad. It should also be noted that the
absorbent article 10 can be a sanitary napkin, a pantiliner, a light
incontinent garment, a feminine care pad, or other type of device
designed to absorb body fluids such as blood, menses7 urine,
perspiration, etc. The absorbent article 10 preferably has an
hourglass shape with a narrow cen-tral portion located between wider
distal end portions. The absorbent 12 has a first surface 14 facing
the body of a user and a second surface 16 aligned approximately
opposite to the first surface 14. The absorbent 12 can have a
uniform thickness or vary in thickness throughouk it's cross-section.
Preferably, the absorbent 12 will be thicker in the middle and
thinner at the distal ends. The absorbent 12 also has a pair of
longitudinally extending arcuate sides 18 and 20. The arcuate
sides 18 and 20 are aligned such that the closest point between them
occurs at a central portion 22 of the absorbent 12. The absorbent 12
can be made out of a hydrophilic mater;al such as cellulose fibers,
wood pulp, regenerated cellulose or cotton fibers, or a blend of pulp
and other fibers. Hydrocolloidal material, commonly referred to as
superabsorbentst can also be added to the hydrophilic material to
increase the absorption capacity.
A fluid permeable cover 24 is positioned adjacent to at least
the first surface 14 of the absorbent 12. The cover 24 is designed
to contact the body of the wearer and can be constructed of a woven
or non-woven, natural or synthetic material which is easily
penetrated by body fluids. Thermoplastic polymer webs made from
fibers or filaments of polyethylene or polypropylene are preferred.
It is also beneficial to form apertures 25 in the cover 24 to
increase the rate at which body fluids can penetrate down into the
absorbent 12.
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A fluid-impermeable baffle 26 is positioned adjacent to at least
the second surface 16 of the absorbent 12 and is sized and configured
to be attaohed to the cover 24. The baffle 26 faces the inner
surfac~, generally the crotch portion in the case of a feminine pad,
of an undergarment (not shown). The baffle 26 will permit the
passage of air or vapor out of the article 10 while blocking the
passage of fluids or liquids. The baflFle 26 can be made from
polymeric films such as polyethylene, polypropylene or cellophane, or
be made from a bicomponent film. A preferred material is ethyl-
vinyl-acetate/polyethylene coextruded film.
The cover 24 and the baffle 26 are! sized and configured to be
attached together to enclose the absorbent 12. Preferably, the
cover 24 is sealed tu the baffle 26 by a peripheral seal 28, best
shown in Fig. 1. The seal 28 can be formed by the use of
commercially available pressure-sensitive adhesives, by the use of
heat and/or pressure, by the use of ultrasonics or by other known
sealing means. The seal 28 will preferably extend continuously
around the periphery of the absorbent 12 but it can also be
discontinuous, if desired. The seal 28 is shown as being located
inward from the peripheral edge 30 of the absorbent article 10 so as
to form a fringe 32. The fringe 32 can have a width of between about
.125-.750 inches, approximately 3.2-19.0 millimeters (mm). A
preferred width is about .312 inches, approximately 7.9 mm. It
should be noted that the fringe 32 can vary in width about the
periphery of the absorbent article 10 although a uniform width is
shown in the drawings. The fringe 32 creates a soft, pliable edge
which is easily deformed by body movement since the cover 24 and the
baffle 26 are not united over the width thereof. A soft fringe 32 is
preferred for it adds comfort to the absorbent article 10 when worn
between the thighs of a person.
The absorbent article 10 also contains a pair of elastic
members 34 and 36 affixed between the cover 24 and the baffle 26 and
located outward of the seal 28. ~he elastic members 34 and 36 are
aligned adjacent to the central portion 22 of the absorbent 12 and
have a width of between about .06-.30 inches, approximately
~ 1.5-7.Ç mm. A preferred width is between about .15-.20 inches,
approximately 3.8-5.0 mm. Depending upon the size and shape of a
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particular product, the use of elastic members wider than about
.30 inches, approximately 7.6 mm can cause problems due to the narrow
width of the fringe 32. The use of wider e1astic members could be
uncomfortable if they come in contact with the thighs and cause
chafing. The elastic members 34 and 36 should also be inset at least
.06 inches, approximately 1.5 mm from the sides of the absorbent
article 10. Preferably, the elastic members 34 and 36 are positioned
midway between the seal line 28 and the outer peripheral edge 30 of
the absorbent article 10 as is clearly shown in Fig. 1.
Referring to Fig. 3 and 4, the elastic members 34 and 36 cause
the adjacent portions of the fringe 32 to acquire an upward and
outward profile in the form of upstanding walls 38 and 40. ~he
walls 38 and 40 assist in preventing sicle leakage of body fluids that
may pool on the upper surface of the cover 24. The walls 38 and 40
will retain the body fluid on the top surface of the cover 24 until
it can be absorbed down into the absorbent 12. The elastic
members 34 and 36 also cause the absorbent article 10 to acquire a
cup-shaped configuration which is best shown in Fig. 4. When the
absorbent article 10 is positionPd with one end resting on a
horizontal plane, an angle alpha (1) is formed by the outer profile
of the edge of the article 10 with the horizontal plane. This angle
is between about 30-90. The benefits associated with this cup-
shaped configuration essentially disappear when the angle alpha (~)
is less than about 30~. It is also difficult to maintain the proper
configuration of the absorbent article 10 should the angle alpha (~)
be greater than about 90.
The elastic members 34 and 36 can be constructed out of any
natural rubber or synthetic elastic including heat sealable and heat
shrinkable materials. An example of a natural rubber elastic is
L-1900 sold by Easthampton Rubb~r Company. Examples of heat sealable
elastics include KRATON~ 1107 sold by Shell Chemica1 Company and
TUFTANE~ TF-410 sold by B.F. Goodrich Company. Examples of heat
shrinkable elastics include crystalline neoprene rubbers sold under
the designation NEOPRENE~ HC by E. I. du Pont de Nemours and Co, Inc.
and polyurethane rubbers sold under the designation ESTANE~ 5710 by
B. F. Goodrich Company. Heat-shrinkable elastics may be easier to
incorporate into certain manufacturing processes because the elastic
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can be applied in a non-elastic state, for example as a film, which
becomes elastic upon the application of heat. lhe following U.S.
patents: 3,639,917 issued to Althouse, 3,819,401 issued to
Massengal~ ~t al. and 3,912,565 issued to Koch et al. teach various
S types of elastic materials applicable to absorbent articles as well
as processes for attaching such elastic. These patents are
incorporated by reference and made a piart hereof. Another method of
incorporating the elastic into the absorbent article 10 is by
utilizing an elastic which can be extruded as a liquid and which upon
cooling becomes an elastic adhesive. This method eliminates the need
for a separate step of adhesively bonding strips of elastic to the
cover 24 and/or to the baffle 26. An example of such an adheslve is
taught in U.S. patent 4,259,220 issued to Bunnelle et al. which is
incorporated by reference and made a part hereof.
The absorbent article 10 is essentially planar when the elastic
members 34 and 36 are applied in a stretched condition and attached
to either the cover 24, the baffle 26 or to both. The elastic
members 34 and 36 distort the planar configuration of the absorbent
article 10 when they return to their relaxed condition. This
distortion pulls the ends of the absorbent article 10 upward toward
each other and forces the central portion 22 to bow inward and
produce a cup-shaped configuration. It has been found that at least
one, and preferably both, of the elastic members 34 and 36 can have a
length of about 10-70% of the overall length of the absorbent
article 10. A more preferred length is between about 10-50% and a
most preferred length is between about 10-30% of the overall length
of the absorbent article 10. The use of shorter strips or bands of
elastic will reduce the cost of the ~inished product. It should also
be noted that the elastic members 34 and 36 can be individual strands
or threads having a round, square or rectangular configuration or
they can consist of two or more strands or threads united or grouped
together to form a ribbon or band. The exact length of the elastic
members 34 and 36 can vary depending upon: the degree of elasticity
of each member, the stiffness and flexibility of the absorbent
article 10, as well as other factors known to those skilled in the
elastic art.
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Experimental testing has shown that the best location for the
elastic members 34 and 36 is to the outside of the seal 28. Uowever,
for certain products, it may be advantageous to position the elastic
members 34 and 36 flush with or slightly to the inside of the
seal 28.
When a self-adhering elastic is not employed, it may be
necessary to provide another seal closer to -the edge of the absorbent
article 10 although this seal need not be continuous. The reason for
the second seal would be to minimize the exposure to the edges of the
cover 24 and thP baffle 26 which also could cause chafing.
Referring again to Figs. 3 and 4, one will notice that the
absorbent article 10 is shown having a number of Fold lines or
constrictions 42 present along the central portion of the baffle 26
and corresponding fold lines or constrictions 44 present along the
central portion of the cover 24 approximate the seal 28. A
transverse fold line 46 is also present in the midsection of the
absorbent article 10. The extent of the fold lines 42, 44 and 46 are
dependent upon the width and length of the elastic members 34 and 36,
the stiffness of the absorbent 12 and the stiffness of the absorbent
article 10 as a whole. The degree of elasticity of the elastic
members 34 and 36 is also relevant. These factors are balanced in
order to produce an absorbent article 10 having an angle alpha (~)
between about 30-90. The presence of fold lines are not as
detrimental in the cup-shape product as they would be in a relatively
flat product because the walls 38 and 40 will retain any body fluids
that may flow along these lines. It should be noted that the deepest
part of the cup occurs at the central port;o~ ~2 of the absorbent
article 10 and this deepest part is designed to be aligned with the
perineal area of the woman when she wears the product. This unique
arrangement assures that the body fluids will impinge upon the
absorbent article 10 in the central portion 22. This is important
because if pooling of the fluid should occur, the walls 38 and 40
will be adiacent to the pool of fluid and prevent side leakage.
The absorbent article 10 further contains a garment attachment
adhesive 48 secured to the exterior surface of the baffle 26 and a
removable peel strip 50. The peel strip 50, which can be a strip of
paper, is designed to prevent foreign contaminates from contacting
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the adhesive 48. The peel strip 50 is designed to be removed just
prlor to use of the absorbent article 10 by the ultimate consumer.
In use, the consumer removes the peel strip 50 and attaches the
product, for exa~ple a sanitary napkin, to the inside surface of an
undergarment so that the article 10 will remain in position relative
to the perineum of the body.
While the invention has been described in conjunction with a
specific embodiment, it is to be understood that many alternatives,
modifications and variations will be apparent to those skilled in the
art in light of the aforegoing description. Accordingly, this
invention is intended to embrace all such alternatives, modifications
and variations which fall within the spirit and scope of the appended
claims.
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