Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
2000-08-23
2002-04-02
Weiss, John G. (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S367000, C604S372000
Reexamination Certificate
active
06365795
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an absorptive article such as a hygienic napkin, panty liners, a disposable diaper or a urine pad. More specifically, the invention relates to an absorptive article which uses a surface material which is bulky and smooth on its surface and has a high performance to hide the discharges absorbed in an absorbent.
2. Related Art
In the prior art, there have been widely used absorptive articles for absorbing the discharges, such as hygienic napkins, panty liners, disposable diapers or urine pads. Each of these absorptive articles is constructed to include: a liquid-permeable surface sheet to come into contact with the skin of a wearer; a liquid-impermeable back sheet; and an absorbent layer sandwiched between the surface sheet and the back sheet. Since this surface sheet is made liquid-permeable, it allows the color of the discharges (e.g., menstrual blood), as passed through the surface sheet and absorbed by the absorbent layer, to be seen through the surface sheet. This may cause the user to feel uncomfortable.
In this respect, it has been investigated to make the once absorbed discharges unseen through the surface sheet. In Unexamined Published Japanese Patent Application No. H3-30764, for example, there is disclosed a facing nonwoven fabric for a sanitary material which is formed of thermoplastic fibers containing titanium dioxide. By incorporating the titanium oxide into the fibers, the whiteness of the nonwoven fabric is enhanced to enhance the hiding properties. This nonwoven fabric has a single-layered structure. In Unexamined Published Japanese Patent Application No. H5-25764, on the other hand, there is disclosed an absorptive article containing a surface material having a two-layered structure. In the individual layers of the surface material, there is contained the titanium oxide to further enhance the hiding properties.
However, the fibers containing the titanium oxide are cut out with a high draft so that they are spun at a low draft. As a result, the fibers containing the titanium oxide generally have a low resin orientation so that their dry elongation percentage is raised while lowering the tensile strength. Therefore, the fibrous web, as formed of the fibers containing the titanium oxide, is lowered in its strength and is also hard to make bulky. Since the bulkiness drops, moreover, the so-called “re-wetting” (i.e., the phenomenon in which the once absorbed body liquids will ooze again to the surface) easily occurs.
Therefore, the above-specified problems are left unsolved even if the nonwoven fabric having the single-layered structure, as disclosed in Unexamined Published Japanese Patent Application No. H3-30764, and the nonwoven fabric having the two-layered structure containing the titanium oxide in each layer, as disclosed in Unexamined Published Japanese Patent Application No. H5-25764, are used as the surface material of the absorptive article such as the hygienic napkin.
SUMMARY OF THE INVENTION
An object of the invention is to provide an absorptive article which uses a bulky surface material having high levels of hiding properties.
According to the invention, there is provided an absorptive article comprising a liquid-permeable surface material on a liquid receiving side,
wherein the surface material is formed of a nonwoven fabric including an upper layer to face the skin of a wearer, and a lower layer positioned under the upper layer,
wherein at least the fibers forming the upper layer contain titanium oxide, and
wherein the fibers forming the lower layer have a lower elongation percentage and a higher tensile strength, as measured according to the JIS L 1013, than those of the fibers forming the upper layer.
The surface material of the invention contains the titanium oxide in its upper layer so that it can have such a high whiteness as to hide the passed discharges effectively. On the other hand, the lower layer is formed of fibers having a relatively low elongation percentage and a high tensile strength so that it can provide the bulkiness and the cushioning properties. As a result, the presence of the upper layer hardly gives a visual uncomfortableness to the wearer, and the presence of the lower layer can improve the wearing feel. Moreover, the presence of the lower layer can easily prevent the re-wetting thereby to improve the wearing feel better. Here, the surface material is soft as a whole.
The fibers forming the lower layer preferably contain no titanium oxide, or the fibers forming the lower layer preferably have a smaller content (in wt. %) of titanium oxide than that (in wt. %) of titanium oxide of the fibers forming the upper layer.
On the other hand, the fibers forming the lower layer preferably have an elongation percentage of 50 to 80%, as measured according to the JIS L 1013, and a tensile strength of 2 to 5 gram/denier (g/d), as measured according to the JIS L 1013.
The fibers forming the upper layer preferably contain 0.5 to 10 wt. % of titanium oxide.
The fibers forming the lower layer preferably contain 0 to 1 wt. % of titanium oxide.
It is preferred that the fibers forming the upper layer are thermoplastic and have a core-sheath structure, the cores of which contain the titanium oxide. In this case, the surface material including the upper layer and the lower layer is preferably an air-through bonded nonwoven fabric.
The lower layer preferably has a basis weight of 7 to 45 g/m
2
.
The upper layer preferably has a basis weight of 5 to 20 g/m
2
.
The fineness of the fibers forming the upper layer is preferably higher than that of the fibers forming the lower layer. In this case, the fineness of the fibers forming the lower layer is preferably 1 to 5 deniers. On the other hand, the fineness of the fibers forming the upper layer is preferably 2 to 6 deniers.
REFERENCES:
patent: 6302872 (2001-10-01), Teranishi et al.
patent: 3-30764 (1991-02-01), None
patent: 5-25764 (1993-02-01), None
patent: 5-176953 (1993-07-01), None
Mizutani Satoshi
Suekane Makoto
Tagami Etsuko
Tomita Katsushi
Bogart Michael
Darby & Darby
Uni-Charm Corporation
Weiss John G.
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