Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
2001-12-03
2004-08-03
Calvert, John J. (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S378000, C604S385101
Reexamination Certificate
active
06770796
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an absorbent article such as sanitary napkin, disposable diaper, incontinence pad, or the like, which is provided with a surface member excellent in moisture-absorbency and liquid-permeability.
2. Description of the Related Art
Absorbent articles such as sanitary napkin, disposable diaper, or the like are typically constructed to include: a liquid-impermeable backsheet on its garment-facing side, a liquid-permeable surface member on its wearer-facing side, and an absorbent core disposed between the backsheet and the surface member.
Characteristics required for the surface member of the absorbent article are as follows:
1) The surface member is excellent in liquid-permeability so as to introduce liquid into the absorbent core;
2) Liquid once absorbed by the absorbent core hardly leaks back through the surface member (i.e., the phenomenon called “rewet back” hardly occurs); and
3) The surface member is excellent in moisture-absorbency so as not to provide unpleasant, stuffy feel to a wearer.
For example, Japanese Unexamined Patent Publication Nos. 1998-219568 and 1994-218007 disclose absorbent articles having surface members in which both liquid-permeability and moisture-absorbency are improved.
In Japanese Unexamined Patent Publication No. 1998-219568, water-absorbency or moisture-absorbency is improved by adhering hydrophilic powder to the surface of a nonwoven fabric treated to be water repellent.
In Japanese Unexamined Patent Publication No. 1994-218007, on the other hand, moisture-absorbency is improved by fixing a moisture-absorbent material to an absorbent article or by mixing a moisture-absorbent material in a surface member.
However, the hydrophilic powder disclosed in Japanese Unexamined Patent Publication No. 1998-219568 is apt to drop off from the surface of the nonwoven fabric, so that there is a difficulty in maintaining absorbency. In addition, since powder material and powder coating are required, production cost becomes relatively expensive.
On the other hand, the moisture-absorbent material disclosed in Japanese Unexamined Patent Publication No. 1994-218007, which is aimed solely at absorbing moisture, has difficulties in fixing it inside of the absorbent article. In addition, the absorbent article is liable to give wet feel to the wearer's skin as a whole. This is because moisture-absorbing capacity is decreased in the surface member as located farther from the moisture-absorbent material, although moisture-absorbency is improved in the vicinity of the moisture-absorbent material. In case where the moisture-absorbent material is mixed in the surface member, on the other hand, fixing of the moisture-absorbent material is typically carried out by hydroentangling method. Therefore, a hydrophilic agent applied to the synthetic resin flows out due to water flow, thereby lowering the water-absorbing capacity.
SUMMARY OF THE INVENTION
The present invention has been worked out in view of the shortcoming in the prior art set forth above. It is therefore an object of the present invention to provide an absorbent article with a surface member excellent in both liquid-permeability and moisture-absorbency.
According to the present invention, there is provided an absorbent article comprising a liquid-permeable surface member, a backsheet and an absorbent core positioned between the surface member and the backsheet,
the surface member being a sheet comprising: first continuous filaments made of hydrophobic synthetic resin and individually extending over the entire length of the surface member; and second continuous filaments made of cellulose acetate and individually extending over the entire length of the surface member.
In the absorbent article of the present invention, the first continuous filaments of hydrophobic synthetic resin allow a liquid to pass through the surface member and also exhibit a function to prevent flow back of the liquid from the absorbent core to the surface of the surface member. On the other hand, the second continuous filaments of cellulose acetate can effectively absorb moisture. Therefore, the surface of the absorbent article is always kept dry, and hardly gives stuffy feel to a wearer. In addition, the surface member has excellent cushioning properties because it is formed from the continuous filaments, providing softness when in contact with the wearer's skin. Accordingly, the absorbent article of the present invention prevents skin roughness of a wearer.
Preferably, the first continuous filaments are treated to be hydrophilic, and hydrophilicity of the second continuous filaments is higher than hydrophilicity of the first continuous filaments.
For example, the surface member comprises: first portions formed from the first continuous filaments; and second portions formed from the second continuous filaments, the first portions alternating with the second portions. Alternatively, the first continuous filaments and the second continuous filaments are mixed with each other in the surface member.
The surface member may further comprise a liquid-permeable substrate sheet underlying the first and second continuous filaments, and the first and second continuous filaments may be at least partly fixed to the substrate sheet. Alternatively, the first and second continuous filaments may be at least partly fixed to each other.
The surface member of the present invention can be readily manufactured by fixing the first and second continuous filaments into the form of sheet.
REFERENCES:
patent: 3727615 (1973-04-01), Duchane
patent: 4360022 (1982-11-01), Usami et al.
patent: 4676786 (1987-06-01), Nishino
patent: 4685914 (1987-08-01), Holtman
patent: 4910064 (1990-03-01), Sabee
patent: 5342336 (1994-08-01), Meirowitz et al.
patent: 5669895 (1997-09-01), Murakami et al.
patent: 5925581 (1999-07-01), Tolbert
patent: 6417427 (2002-07-01), Roxendal et al.
Furuya Kodai
Hayashi Hiroo
Igaue Takamitsu
Calvert John J.
Darby & Darby
Stephens Jacqueline F
Uni-Charm Corporation
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