Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
1999-10-01
2004-03-02
Lo, Weilun (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S367000
Reexamination Certificate
active
06700034
ABSTRACT:
BACKGROUND OF THE INVENTION
To prevent leakage of body exudates from absorbent articles such as feminine care pads or napkins and disposable diapers, it is desirable that the exudates not reach the edges of the absorbent material in the article. A “center fill” strategy is desirable for leakage control, wherein fluids are preferentially held in a central region of the article. Unfortunately, in traditional absorbent articles, there is generally no barrier to bulk flow or capillary wicking from the target region to the edges of the article, so leaking from the edges of the article is a persistent problem. Thus, in traditional articles, fluid entering the center of the article still has the potential to travel to the sides and leak. Flow from the center to the sides can be especially rapid when the article is compressed, bringing the wet central portion of the article in contact with absorbent material at the sides of the article.
The ability of an absorbent article to promote center fill and reduce leakage depends on the goodness of body fit achieved by the article in use. In sanitary napkins and other absorbent articles, the article as worn is often compressed laterally by the legs of the wearer, causing significant deformation of the article. In many conventional articles, the deformation is random or uncontrolled, resulting in a variety of product configurations that often may be inadequate for good uptake and fluid distribution in the article.
Past efforts to improve body fit and promote liquid uptake in the center of the article have included three-dimensional structures with elevated central members resting above the plane of a flat absorbent core. The elevated member can be a cylinder or an inverted U-shaped tube, for example. However, the elevated member adds substantially to the bulk of the article, potentially reducing comfort when worn and certainly decreasing packaging efficiency since fewer articles can fit into a package when the articles are no longer flat. Further, the article with an elevated central member can still suffer from leakage and smearing from fluid leaving the sides of the member.
Many other articles have been proposed for either improved body for or leakage protection which suffer from complexity of design and high cost, with multiple components comprising a variety of absorbent materials in the absorbent core.
What is needed is an article with good center fill performance that can reduce leakage to the sides of the article and provide good body fit with a simplified, low-cost absorbent core.
SUMMARY OF THE INVENTION
It has been discovered that a useful absorbent article with good leakage control can be produced with an absorbent core comprising a unitary absorbent layer and a thin, flexible wicking barrier, such as a polymeric film, which passes through the unitary absorbent layer along a portion of a boundary dividing the unitary absorbent layer into a central portion and an outer portion, wherein the two portions are nevertheless contiguous. The boundary comprises at least one slit and desirably two spaced apart slits through which the wicking barrier passes and further comprises a joining zone contiguously connecting the central portion with the outer portion. The interaction of the wicking barrier with the central and outer portions of the unitary absorbent layer results in an absorbent article having excellent leakage control and body fit. Further, the article offers a simple design in which a single piece of absorbent material forms the primary absorbent layer yet has multiple portions with fluid isolation therebetween provided by a wicking barrier. In a preferred embodiment, body fit is further enhanced by a deflection control element cooperatively associated with the central portion of the unitary absorbent layer.
As used herein, the term “unitary” means that all portions of a component are joined together without a physical discontinuity such as a gap or cut completely separating or severing one portion from another. Thus, a unitary object could be a single piece of a web provided with slits that do not completely sever the web into two or more pieces, or a single section of a laminated absorbent material with each ply bonded to adjacent plies. A section of web with a central cutout region that can be completely removed from the web without any need for tearing or cutting or disengaging entangled fibers is not unitary, even if the cutout section is placed back onto the web, for a physical discontinuity clearly has been created by the process of removing or cutting out one section.
Hence, in one aspect, the invention resides in an absorbent article for use on the body of a wearer, the absorbent article having two longitudinal sides, a target zone and a body side, the absorbent article comprising:
a) a liquid impervious backsheet;
b) a liquid pervious topsheet attached to the backsheet;
c) an absorbent core disposed between the topsheet and the backsheet comprising a unitary absorbent layer having a thickness, the unitary absorbent layer comprising a central portion and an outer portion separated in part by one or more slits passing through the thickness of the unitary absorbent layer and further comprising a boundary between the outer portion and the central portion; and
d) a wicking barrier spanning a horizontal distance above the body-side surface of the outer portion of the unitary absorbent layer and spanning a vertical distance in the one or more slits of the unitary absorbent layer.
In another aspect, the invention resides in an absorbent article for use on the body of a wearer, the absorbent article having two longitudinal sides, a target zone and a body side, the absorbent article comprising:
a) a liquid impervious backsheet;
b) a liquid pervious topsheet attached to the backsheet;
c) a unitary absorbent layer disposed between the topsheet and the backsheet, the unitary absorbent layer having a thickness, and comprising a central portion and an outer portion separated by a boundary comprising a slit; and
d) a wicking barrier spanning a horizontal distance on the surface of the outer portion of the unitary absorbent layer and spanning the thickness of the unitary absorbent layer in a portion of the slit.
In another aspect, the invention resides in a method of making an absorbent article having a body-side comprising:
a) providing a layer of absorbent material;
b) slitting a portion of the layer of absorbent member to define a central portion and an outer portion of the absorbent layer with a boundary separating the central portion from the outer portion, wherein the boundary comprises at least one slit and a joining zone between ends of the at least one slit, the joining zone connecting the outer portion to the central portion;
c) providing a first section of wicking barrier material along a portion of the boundary between the central portion and the outer portion of the layer of absorbent material, wherein the wicking barrier material spans a vertical distance in the layer of absorbent material;
d) providing a second section of wicking barrier material on or above the body-side surface of the outer portion of the layer of absorbent material;
e) sandwiching the layer of absorbent material a topsheet and a backsheet to form an absorbent article.
In still another aspect, the invention resides in a method of making an absorbent article having a body-side comprising:
a) providing a unitary layer of absorbent material;
b) providing the unitary layer of absorbent member with at least one slit that forms a longitudinal boundary dividing the longitudinal sides of a central portion of the unitary layer from an outer portion of the unitary layer;
c) inserting a segment of wicking barrier material through a portion of the slit to form a vertical wicking barrier between part of the central portion of the unitary layer and the outer portion of the unitary layer;
d) further providing a horizontal component of a wicking barrier above the body-side surface of the unitary layer to form a composite of a unitary layer and one or more wicking barrier
Chen Fung-jou
DiPalma Joseph
Lindsay Jeffrey Dean
Kidwell Michele
Kimberly--Clark Worldwide, Inc.
Lo Weilun
Pauley Petersen & Erickson
LandOfFree
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