Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
2002-10-31
2004-02-10
Lo, Weilun (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S379000
Reexamination Certificate
active
06689935
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 (the place where intake of fluids occurs) 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 through absorbent material directly 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 central humps or 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 article with an elevated central member can still suffer from leakage and smearing from fluid leaving the sides of the member. Further, deformation of the entire article may be poorly controlled, resulting in poor body fit in many cases even with a central elevated region.
What is needed is an absorbent article with internal barriers to prevent leakage to the sides and offering good control of the deformation of the absorbent material when worn such that absorbent material is placed close to the source of body exudates. What is needed further is a thin absorbent article with good center fill performance that can reduce leakage and offer excellent body fit through the efficient use of a small amount of absorbent material while maintaining comfort.
SUMMARY OF THE INVENTION
It has been discovered that a layered absorbent core with a horizontal wicking barrier between two superposed layers provides opportunities for improved leakage prevention, better body fit, and more efficient use of the absorbent material of the core if certain design principles are followed to promote the upward deflection of the central portion of the absorbent core toward the body of the wearer. The design principles require that the absorbent core be divided into two parts, a lower absorbent member and a central absorbent section, with a horizontal wicking barrier separating the two parts to reduce the tendency for fluid to flow through the absorbent material from the central target region of the article toward the longitudinal sides of the article.
Hence, in one aspect, the invention resides in an absorbent article for use on the body of a wearer, the absorbent article having a longitudinal centerline, a transverse centerline, 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 lower absorbent member disposed above the backsheet, the lower absorbent member comprising a pair of spaced apart, substantially longitudinal crease lines in the target zone disposed on opposite sides of the longitudinal centerline of the article, the pair of crease lines having a distance therebetween;
d) a horizontal wicking barrier disposed above the lower absorbent member;
e) a middle absorbent member having a width less than the distance between the crease lines in the target zone, the middle absorbent member being disposed above the horizontal wicking barrier; and
f) an upper absorbent member having longitudinal sides and a width in the target zone greater than the width of the middle absorbent member and less than the width of the horizontal wicking barrier, disposed above the middle absorbent member and beneath the topsheet.
In another aspect, the invention resides in an absorbent article having a target zone, the absorbent article comprising:
a) a liquid impervious backsheet;
b) a lower absorbent member disposed above the backsheet;
c) a horizontal wicking barrier disposed over the lower absorbent member, the wicking barrier having a width in the target zone;
d) a middle absorbent member disposed above the wicking barrier and having a maximum width in the target zone;
e) an upper absorbent member disposed above the middle absorbent member having a width in the target zone no less than the maximum width of the middle absorbent member in the target zone, the upper absorbent member being predisposed to deflect upward during laterally inward compression of the absorbent article; and
f) a topsheet connected to the backsheet.
In another aspect, the invention resides in an absorbent article having a target zone, a longitudinal direction, a transverse direction, a vertical direction substantially normal to both the longitudinal and transverse directions, and a body side, the absorbent article comprising:
a) a liquid impervious backsheet;
b) a lower absorbent member disposed above the backsheet;
c) a horizontal wicking barrier disposed over the lower absorbent member, the horizontal wicking barrier having a width in the target zone;
d) a pre-shaped upper absorbent member disposed above the horizontal wicking barrier, the pre-shaped upper absorbent member being shaped to define a medial hump therein and to define a voidspace between the horizontal wicking barrier and the medial hump, the pre-shaped upper absorbent member having a width in the target zone no greater than the width in the target zone of the horizontal wicking barrier; and
e) a topsheet disposed above the pre-shaped upper absorbent member and attached to the backsheet.
The voidspace of the above article can optionally but desirably be filled in part with a middle absorbent member including loose fibrous material such as hardwood nits, absorbent particulates, high-bulk fluff pulp, tissue layers, and the like. Generally, the pre-shaped upper absorbent member is geometrically predisposed to flex upward during laterally inward compression.
In another aspect, the invention resides in a method for producing an absorbent article having a longitudinal centerline and a transverse centerline substantially normal to the longitudinal centerline comprising:
a) providing a backsheet;
b) disposing a substantially planar lower absorbent member above the backsheet, the lower absorbent member having a width along the transverse centerline of the article and comprising longitudinal crease lines therein;
c) disposing a horizontal wicking barrier over the lower absorbent member;
d) disposing a middle absorbent member over the horizontal wicking barrier, the middle absorbent member being substantially centered about the longitudinal centerline of the article and having a width substantially less than the width of the lower absorbent member along the transverse centerline of the article;
e) disposing an upper absorbent member over the middle absorbent member, the upper absorbent member having a width along the transverse centerline of the article greater than the width of the middle absorbent member;
f) disposing a topsheet above the upper absorbent member and the lower absorbent member; and
g) securing the topsheet to the backsheet.
In still another aspect, the invention resides in a method for producing an absorbent article
Bednarz Julie Marie
Chen Fung-Jou
DiPalma Joseph
Lindsay Jeffrey Dean
Kidwell Michele
Kimberly--Clark Worldwide, Inc.
Lo Weilun
Pauley Petersen & Erickson
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