Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
2000-10-27
2003-12-16
Lo, Weilun (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S385101, C604S368000, C604S369000, C604S374000, C604S375000
Reexamination Certificate
active
06664439
ABSTRACT:
GENERAL FIELD OF THE INVENTION
The present invention relates to absorbent articles which are primarily designed to receive and retain bodily discharges such as urine. Such articles are disposable hygiene articles like baby diapers, training pants, adult incontinence articles and the like.
BACKGROUND/PRIOR ART
Absorbent Articles for receiving and retaining bodily discharges such as urine or feces such as disposable diapers, training pants, adult incontinence articles are well known in the art, and significant effort has been spent against improving their performance. The ability to provide better performing absorbent articles such as diapers has been contingent on the ability to develop relatively thin absorbent cores or structures that can acquire and store large quantities of discharged body fluids, in particular urine.
In this regard, the use of certain absorbent polymers often referred to as “hydrogels”, “superabsorbents” or “hydrocolloid” or “hydrogel forming” material has been particularly important. See, for example, U.S. Pat. No. 3,699,103 (Harper et al), issued Jun. 13, 1972, and U.S. Pat. No. 3,770,731 (Harmon), issued Jun. 20, 1972, that disclose the use of such absorbent polymers (hereafter “hydrogel-forming absorbent polymers”) in absorbent articles. Indeed, the development of thinner diapers has been the direct consequence of thinner absorbent cores that take advantage of the ability of these hydrogel-forming absorbent polymers to absorb large quantities of discharged body fluids, typically when used in combination with a fibrous matrix. See, for example, U.S. Pat. No. 4,673,402 (Weisman et al), issued Jun. 16, 1987 and U.S. Pat. No. 4,935,022 (Lash et al), issued Jun. 19, 1990, that disclose dual-layer core structures comprising a fibrous matrix and hydrogel-forming absorbent polymers useful in fashioning thin, compact, nonbulky diapers. See also, U.S. Pat. No. 5,562,646 (Goldman et al.), issued Oct. 8, 1996 and U.S. Pat. No. 5,599,335 (Goldman et al.), issued Feb. 4, 1997, both of which relate to absorbent cores comprising regions of high concentrations of hydrogel-forming polymer, where the polymer forms a gel-continuous fluid transportation zone upon swelling.
In addition or alternatively to the use of hydrogel-forming absorbent polymers as the primary component in absorbent article storage structures, the use of polymeric foam materials derived from high internal phase water-in-oil emulsions (“HIPEs”) has been identified. See, e.g., U.S. Pat. No. 5,260,345 (DesMarais et al.), issued Nov. 9, 1993, U.S. Pat. No. 5,387,207 (Dyer et al.) issued Feb. 7, 1995, and U.S. Pat. No. 5,560,222 (DesMarais et al.), issued Jul. 22, 1997.
Further disclosure is made of structures having a low capacity in the regions between the legs of the wearer such as in PCT application U.S. Ser. No. 97/050,46, filed on Mar. 27, 1997, relating to the movement of fluid through certain regions of the article comprising materials having good acquisition and distribution properties to other regions comprising materials having specific liquid storage capabilities.
Further prior art aimed at providing material with improved fluid acquisition/distribution performance, such as by providing “surge management means” between the absorbent core and the topsheet, see for example EP-A-0.397.110 or EP-A-0.312.118.
Other documents disclose Absorbent articles with distribution layers underlying a storage layer which has a “fluid passage way” allowing fluid to pass from the surface to the underlying distribution layer without penetrating the absorbent materials in a microscopic view (see for example EP-A-0.565.606 or EP-A-0.343.940). Alternative designs were described, where the fluid was enabled to penetrate through the overlaying storage layer because this layer has a relatively low ultimate storage capacity, such as by having only small amounts of superabsorbent material, see for example EP-A-0.512.010.
In U.S. Pat. No. 5,454,800 (Hirt et al.), absorbent articles are disclosed, comprising at least a first and a second absorbent member in a layered arrangement, such that lower layer—for example a paper tissue—has better wicking properties than the first layer, which can be made from large pore materials such as co-form or air-laid tissue webs, or which can have gaps or apertures to allow fluid penetration into the under-laying layer.
Yet other articles describe the use of superabsorbent materials for being used in absorbent structures, whereby the materials exhibit a liquid permeability, expressed in “Saline Flow Conductivity”, end as described in U.S. Pat. No. 5,599,335.
A further class of documents describe materials having improved fluid distribution properties, such as having high flux as disclosed in EP-A-0.809.991 or high wicking capability as disclosed in copending U.S. patent application Ser. No. 09/042,418, filed Mar. 13, 1998 by T. DesMarais et al. titled “Absorbent materials for distributing aqueous liquids”, now U.S. Pat. No. 6,013,589.
However, a problem with using distribution materials as described in such art is that a relatively high capillary absorbent pressure is required for the storage materials to drain the distribution materials.
Thus, there is still a need to improve towards well performing articles, which provide good acquisition, good distribution without detrimentally affecting comfort of the wearer, such as providing low thickness, prevent a hard feel especially on the outer side of the article (often referred to as “poly-pockmarking”), which even might cause liquid to penetrate through. In particular, the combination of low thickness with small core sizes resulted in the need for overall “basis capacities”, i.e. high amounts of fluid storage capacity per unit area.
OBJECTS OF THE INVENTION
Henceforth, it is an object of the present invention to provide an absorbent article with improvements in the above mentioned areas, in particular to provide an absorbent article which is easy to manufacture, even on conventional production lines.
It is a further object of the present invention to provide an absorbent article, which exploits the benefits of particularly suitable distribution materials with fluid storage materials or members of conventional type.
SUMMARY
The present invention is an absorbent article, such as for use in hygienic applications, which has an ultimate fluid storage region, and a fluid distribution region positioned between the ultimate storage region and the garment oriented surface of the article, which is in fluid communication with the ultimate fluid storage region, whereby the ultimate fluid storage region comprises material which has (1) a Capillary Sorption Desorption Capacity at 100 cm (CSDC 100) of at least 10 g/g; which further has (2) a Capillary Sorption Desorption Capacity at 0 cm (CSDC 0) higher than said CSDC 100 and which thereby has (3) a Loosely Bound Liquid Capacity (LBLC) as the difference between (CSDC 0 and CSDC 100); and which has (4) a Capillary Sorption Desorption Release Height when 50% of said LBLC are released (CSDRH 50) of less than 60 cm. Further, the liquid distribution layer comprises material having a Capillary Sorption Absorption Height at 30% of its maximum capacity (CSAH 30) of at least 25 cm.
The present invention also relates to an absorbent article, having a fluid receiving surface oriented towards the wearer during use, and a garment oriented surface opposite said fluid receiving surface, further having an ultimate fluid storage region, and a fluid distribution region positioned between said ultimate storage region and said garment oriented surface, and in fluid communication with said ultimate fluid storage region, wherein said distribution region comprises fluid distribution material having a Capillary Sorption Absorption Height at 30% of its maximum capacity (CSAH 30) of at least 35 cm, and wherein the ultimate fluid storage region comprises ultimate fluid storage material which has a Capillary Sorption Desorption Capacity at 100 cm (CSDC 100); and which further has a Capillary Sorption Desorption Capacity at 0 cm (CSDC 0
Arndt Silke
Ehrnsperger Bruno Johannes
Lavon Gary Dean
Link Andrea Lieselotte
Neumann Frank
Hughett Eileen L.
Lo Weilun
Milbrada Edward J.
Patel Ken K.
Stephens Jacqueline
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