Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
2000-10-06
2003-09-09
Lo, Weilun (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S379000, C604S385010
Reexamination Certificate
active
06617490
ABSTRACT:
BACKGROUND OF THE INVENTION
To prevent leakage of body exudates from absorbent articles such as feminine care pads or napkins, disposable incontinence pants or pull-ups, menstrual pants, and disposable diapers, it is desirable that the exudates not reach the edges of the absorbent material in the article. To establish good contact of the article with the body and to provide good fluid intake and flow control properties, there have been many efforts to create three-dimensional absorbent structures rather than the flat, two-dimensional structures that have predominated the art. Such three-dimensional structures have included central humps, flow channels, side dams, openings in the absorbent core, and corrugation of polymeric nonwoven webs.
Contoured absorbent cores and absorbent articles in general have commonly been provided by adding additional material to areas intended to be elevated. For example, central humps are commonly provided by the placement of additional absorbent material in the core. In use, the additional material often collapses or is more heavily densified, being exposed to relatively higher loads than the less elevated portions of the web and also generally being exposed to higher saturation levels of fluid, which tends to weaken the structure and promote collapse. Further, absorbent cores with regions of high basis weight can result in discomfort when the elevated, high-basis weight regions shift against the body and press against unintended areas.
When humps have been provided for purposes of improved body fit, the focus has generally been on providing a transverse profile capable of contacting the anatomy of the user in the crotch region. What has generally been overlooked is the need to match the shape of the users body along a longitudinal axis extending well past the central crotch region.
What is needed is an absorbent article with an improved three-dimensional absorbent core capable of providing good body fit and flow control.
SUMMARY OF THE INVENTION
It has been discovered that high absorbent capacity and/or good flow control can be achieved in the absorbent core of an absorbent article by providing the article with an absorbent layer comprising a three-dimensional molded cellulosic web having a portion of water-resistant binder material therein. The molded cellulosic web can have a substantially uniform basis weight and thickness prior to molding, but is molded to have a plurality of elevated regions offering a distinctive profile well suited for conforming to the body of the wearer. The molded web can also be adapted for providing significant void volume beneath the upper absorbent layer and preventing leakage to the sides of the article.
It has further been discovered that such molded webs can be produced from cellulosic webs comprising heat-sensitive binder material (thermoplastic or thermally curable) by means of an online process in which the web is held against a molding substrate after or during application of energy to the web, causing the web to conform to the molding substrate and form bonds that lock the web into the shape of the molding substrate. The web can be held against the molding substrate by pneumatic forces, tension in the web itself, tension applied by a belt or wire, restraining forces from a backing surface such as a second surface that conforms to the molding substrate, and the like. The molding substrate can be metal (e.g., aluminum, steel, copper, brass, titanium, and the like), glass, ceramic, plastic, a composite material, and the like, and can be gas permeable or impermeable.
In some embodiments, the molded web has a body-side surface topography comprising a central hump having an oval shape elongated in the longitudinal direction, and a plurality of molded flexure zones (either linear or arcuate, continuous or discontinuous) having a component extending in the transverse direction and disposed between the central hump and at least one longitudinal end of the molded web. The molded flexure zones assist in permitting an initially flat article to readily conform to the shape of the wearer's body along the longitudinal axis of the article. Such articles can adapt to fit the body of the wearer during the dynamic conditions of use, thereby providing both comfort and leakage prevention.
Molded structures within the scope of the present invention include those having slotted vertical gaps that offer an entranceway for gushes of body fluids, as well as anatomically conforming shapes adapted to not only intercept and direct flowing fluids, but to guide the flexure of the article in use to better conform to the body. The article can comprise a plurality of longitudinal slits or longitudinal flaps (formed from a plurality of webs or a single web folded or pleated to form flaps) that can trap fluid flowing from the center of the article to the sides thereof, and that can adapt to fit the users body in use. The centrally inward ends of slit regions or flaps can, in some embodiments suited for sanitary napkins and other articles for feminine care, adapt to the shape of the labia majora of the user and provide excellent conformance to the body for good leakage control and comfort in use.
Articles according to the latter concept can have a central elongated hump, one or more longitudinal flow channels (depressed or less elevated regions between adjacent longitudinal elevated regions), and a plurality of transverse flexure zones (hereafter described) away from the central hump to cause the article to flex toward the body when compressed from the sides.
The energy to mold the web can be applied by microwave radiation, radiofrequency energy, or other electromagnetic radiation sources, as well as by heated air or by conduction with heated surfaces. When microwave energy is applied, the web can incorporate binder materials such as thermoplastic binder fibers that are sensitive to microwave radiation by virtue of a high dipole moment. In one embodiment, microwave energy is applied to the moving web as it passes through an opening in a microwave resonance chamber, where microwave energy is focused into the web. Alternatively, the energy can be applied in the form of heated gas passing through the web, or by conduction from one or more heated molding surfaces, or by application of ultrasonic energy, infrared energy, and the like. Details of various energy application methods are described more fully in commonly owned U.S. application Ser. No. 09604039, “Method of Making Molded Airlaid Webs for Use in Absorbent Articles,” filed the same day as the present application, herein incorporated by reference.
The applied energy heats the binder material, promoting fusion of a portion of the binder material to join fibers in the web in the case of a thermoplastic binder, or promoting curing in the case of thermosetting materials or heat-curable crosslinking agents. The resulting molded web can be cut into discrete sections suitable for incorporation into an absorbent article. The section of molded web can have any one or more of the following characteristics: a substantially uniform density, an apparent thickness at least 50% greater than the original thickness of the unmolded web, an Overall Surface Depth (hereafter defined) of at least 0.5 mm, a Surface Height of at least 1 mm, a wet compressed bulk at least 50% greater than that of the unmolded web, a longitudinally elongated central hump and one or more transverse flexure zones between the hump and one or more of the longitudinal ends of the section of the web, and one or more longitudinal flow channels between elevated longitudinal structures on the section of the web.
The cellulosic web to be molded can be any cellulosic web comprising binder material and specifically can be an airlaid web formed with binder material or an airformed web to which binder material is subsequently added or a combination thereof, and may contain one or more layers of similar or dissimilar materials, such as an airlaid web joined to a wetlaid tissue or an airlaid web disposed over an airformed web, or two airlaid w
Bednarz Julie Marie
Chen Fung-jou
Lindsay Jeffrey Dean
Makoui Kambiz Bayat
Perkins Cheryl Anne
Kimberly--Clark Worldwide, Inc.
Lo Weilun
Pauley Petersen Kinne & Erickson
Stephens Jacqueline
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