Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Coating or impregnation functions biologically
Reexamination Certificate
1998-10-30
2002-02-26
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Coated or impregnated woven, knit, or nonwoven fabric which...
Coating or impregnation functions biologically
C442S059000
Reexamination Certificate
active
06350711
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an absorbent material for absorbing blood-containing fluids. More particularly, this invention relates to an absorbent material for use in personal care absorbent articles, which are particularly adapted for absorbing various blood-containing bodily fluids while providing comfort and fit to the wearer, such as catamenial articles such as sanitary napkins and pads, wound dressings, and the like. The absorbent material may be a woven material, nonwoven material or a combination of both woven and nonwoven materials.
2. Description of Prior Art
A wide variety of disposable absorbent articles for collecting bodily fluids are known in the art. Commercial absorbent articles include diapers, sanitary napkins, training pants, and incontinent care pads, wound dressings, and the like. Disposable products of this type include some functional elements for receiving, absorbing, and retaining fluids. Typically, such absorbent articles have an absorbent core containing cellulosic fibers, for example, wood pulp fluff, particles of highly absorbent materials, for example, superabsorbents, and an admixture of cellulosic fibers and superabsorbents. Typically, such articles include a fluid-permeable cover sheet or topsheet which typically faces the body of the user, an absorbent core, and a fluid-impermeable backsheet.
Cover sheet materials are utilized for the transport of bodily fluids into the absorbent core of personal care absorbent articles and, thus, materials used for cover sheet applications must manage distinctly different body excretions, depending upon the application and the product type. Some products must manage fluids, such as urine, while others must manage proteinaceous and viscoelastic fluids, such as menstrual discharge and fecal matter. The management of viscoelastic menstrual discharge by feminine care products such as sanitary pads and napkins is exacerbated due to the variations in composition and rheology over a broad range of elasticity. Fluid management in feminine care applications requires control of absorption of bodily fluids, control of fluid retention in the cover, control of stain size and intensity, control of rewet of fluid back to the surface, and control of the release of fluid to the absorbent core.
There are several factors which influence the flow of liquids in fibrous structures including the geometry of the pore structure in the fabrics, the nature of the solid surface (surface energy, surface charge, etc.), the geometry of the solid surface (surface roughness, grooves, etc.), the chemical/physical treatment of the solid surface, and the chemical nature of the fluid. One problem associated with absorbent articles intended for use in handling fluids comprising blood components such as feminine care products and wound dressings is the tendency of red blood cells to block the pores of the materials used for absorption of fluids in such products. Typical of such porous materials are nonwoven or fibrous web materials. The blockage of the pores of the nonwoven or fibrous web materials by the red blood cells results in a reduction in the fluid intake and the wicking capabilities of such products. In addition, in the case of feminine care products such as sanitary pads and napkins, the blockage of pores of nonwoven materials used therein by red blood cells results in increased staining. In the case of feminine care products comprising superabsorbents, the red blood cells attach themselves to the superabsorbents, resulting in blockage of the superabsorbents and a significant reduction in fluid uptake.
In the case of feminine care products such as sanitary pads and napkins, women have come to expect a high level of performance in terms of comfort and fit, retention of fluid, and minimal staining. Of utmost importance, leakage of fluid from the pad onto undergarments is regarded as totally unacceptable.
Improving the performance of feminine care products continues to be a formidable undertaking, although numerous improvements have been made in both their materials and structures. However, solutions addressing the issues arising from the presence of red blood cells in blood or menses in feminine care products, as well as other absorbent materials for handling blood-containing fluids, have not been satisfactorily implemented. It is apparent that a system which effectively handles red blood cells in a manner which addresses the issues set forth hereinabove will not only improve the distribution of incoming fluids by the absorbent material, but will also reduce the tendency toward premature failures of these absorbent articles.
Methods for separating or removing red blood cells from blood-containing fluids generally fall into two categories, agglutination (agglomeration) in which the red blood cells agglomerate, thereby enabling them to be more readily separated from the remaining fluid component, for example, by filtration, and lysing in which the membranes of the red blood cells are disrupted, resulting in a breaking down or breaking apart of the red blood cells. Agglomeration is known to occur, for example, in the presence of certain antibodies. However, we are unaware of any personal care absorbent articles employing these red blood cell management techniques.
SUMMARY OF THE INVENTION
Accordingly, it is one object of this invention to provide a blood-containing fluid absorbent material having the capability of reducing the level of red blood cells in the fluid.
It is one object of this invention to provide a feminine care absorbent product having improved fluid handling, including improved fluid intake and wicking, and reduced staining characteristics.
It is another object of this invention to provide a feminine care absorbent product having means for partitioning components of menses, thereby enabling improved fluid handling and reduced staining.
It is another object of this invention to provide a method and system which improves the intake of fluid by superabsorbents which may be present in feminine care absorbent products.
These and other objects of this invention are achieved by a material for absorbing a blood-containing fluid comprising an absorbent material treated with a fluid treatment agent whereby red blood cells within a blood-containing fluid absorbed by the absorbent material are agglomerated or lysed. In accordance with a particularly preferred embodiment, the absorbent material comprises a porous nonwoven web material treated with said fluid treatment agent. In accordance with one embodiment of this invention, the fluid treatment agent is an agglomerating agent which causes the red blood cells in the blood-containing fluid to agglomerate, thereby enabling them to be physically separated from the blood-containing fluid, leaving a fluid that is easier to absorb and less strongly colored. In accordance with another embodiment of this invention, the fluid treatment agent is a cell lysing agent.
The porous nonwoven web material may be produced by any number of means known to those skilled in the art. In accordance with one embodiment of this invention, the nonwoven web material comprises a gradient of pore sizes produced by layering of nonwoven web layers, each layer of which has an average pore size different from the average pore sizes of other nonwoven web layers, forming a porosity gradient nonwoven web material. When disposed between the cover sheet and the liquid impervious backing material of a personal care absorbent article, the porosity gradient nonwoven web material is disposed such that larger average pore sizes are oriented toward the cover sheet and the average pore size of the nonwoven web material decreases in the direction of the liquid impervious backing material. As a result, the porosity gradient nonwoven web material acts as a “depth filter” wherein the agglomerated red blood cells become trapped within the larger size pores of the porosity gradient nonwoven web material. However, care must be taken in selecting the pore size gradient to insure that the f
Damay Emmanuelle Cecile
Lindon Jack Nelson
Potts David Charles
Yavich Dmitry
Young Matthew David
Kimberly--Clark Worldwide, Inc.
Morris Terrel
Pauley Petersen Kinne & Fejer
Pratt Christopher C.
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