Stock material or miscellaneous articles – Structurally defined web or sheet – Including aperture
Reexamination Certificate
2000-02-04
2002-11-12
Pyon, Harold (Department: 1772)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including aperture
C428S131000, C428S132000, C428S138000, C604S365000, C604S366000, C604S383000, C604S385010, C604S385101
Reexamination Certificate
active
06479130
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a flexible sheet suitable as stock material of disposable body fluids absorbent garment such as a disposable diaper, a urine absorbent pad or a sanitary napkin or a disposable garment such as a disposable gown used in medical facilities.
FIG. 7
of the accompanying drawings is a perspective view showing a plastic sheet
110
formed with microapertures described in Japanese Patent Application Disclosure No. 1987-57551 and claimed to offer a soft touch. The plastic sheet
110
is described to be suitable as a top- and/or backsheet of a disposable diaper and formed on its surface with a plurality of cylindrical projections
120
. These projections
120
are formed, in turn, on their upper ends with microapertures
125
, respectively. Such a sheet is claimed to offer a soft cloth-like touch.
FIG. 8
of the accompanying drawings is a perspective view showing a sanitary napkin
200
described in Japanese Patent Application Disclosure No. 1995-328061. In the case of the napkin, a topsheet
210
comprises a nonwoven fabric
211
and a plurality of stripe-like plastic sheets
212
bonded to the upper surface of the nonwoven fabric
211
. The stripe-like plastic sheets
212
extend in parallel one to another longitudinally of the napkin
200
. The nonwoven fabric
211
has its density lower in the zones defined between each pair of the adjacent plastic sheets
212
,
212
than the zones underlying the respective plastic sheets
212
. Menstrual discharge transfers from the low density zones toward the high density zones which are covered with the plastic sheets
212
. Consequently, a stain of menstrual discharge is not remarkable, if any.
When the plastic sheet used as the topsheet and/or the backsheet of a disposable diaper or a sanitary napkin is said to offer a soft touch as the sheet comes in contact with the wearer's skin, the standard of judgement, in other words, a touch to which the touch offered by the plastic sheet is compared is generally a touch offered by a woven or nonwoven fabric made of natural or synthetic fibers or the like.
In the case of the plastic sheet described in the Japanese Patent Application Disclosure No. 1987-57551, the peripheries of the microapertures formed at the top ends of the respective cylindrical projections are broken into parts like pedals. As far as the surface of the plastic sheet is concerned, a comfortable soft touch will be obtained as the wearer's skin comes in contact with the sheet. However, a plurality of cylindrical projections formed on the plastic sheet may often be far from decreasing a rigidity of the sheet itself and rather increase the rigidity. Accordingly, it will be difficult for the known plastic sheet to obtain a softness as comfortable as the softness offered by a woven or nonwoven fabric.
The topsheet described in Japanese Patent Application Disclosure No. 1995-328061 will be able to offer a desired touch which is soft and comfortable for the wearer's skin so far as each section of the nonwoven fabric exposed between each pair of adjacent stripe-like plastic sheets is adequately large. However, if a relatively thick plastic sheet is used to form the stripe-like plastic sheets extending on the topsheet, it is concerned that respective side edges of these stripe-like plastic sheets might act like knife edges and unacceptably irritate the wearer's skin.
SUMMARY OF THE INVENTION
An object of this invention is to solve the problems inevitably encountered by the known articles as have been described above when the plastic sheet is used as one of stock materials for a body fluids absorbent garment such as a disposable diaper or a garment such as a disposable gown used in medical facilities.
According to this invention, there is provided a flexible sheet having upper and lower surfaces and adapted to be used in disposable garment.
The flexible sheet comprises a plastic sheet forming a part of the upper surface and a fibrous assembly joined to a lower surface of the plastic sheet to form the remaining part of the upper surface and entire the lower surface of the flexible sheet; the plastic sheet comprises a plurality of substantially flat zones, each having a thickness of 0.001~0.05 mm and a width of 0.03~1 mm, extending in parallel one to another in: one direction, a plurality of slit zones extending in the one direction to space each pair of the adjacent substantially flat zones from each other, bridge zones extending from mutually opposite edges of the adjacent substantially flat zones across the slit zones to connect these adjacent substantially flat zones, and rising zones rising on the upper surface of the plastic sheet repeating rise and fall substantially in saw-tooth-shape in the one direction; and the fibrous assembly comprises component fibers assembled together by mechanical intertwining, heat-sealing or adhesive bonding of the component fibers wherein the fibrous assembly contains at least one of thermoplastic synthetic fibers, chemical fibers and natural fibers and the component fibers partially extend upward in the slit zones of the plastic sheet.
This invention includes the other preferred embodiments as follow:
(1) Most of the slit zones have a width of 0.05~1 mm and a length corresponding to the width multiplied by 1.5 or larger.
(2) The bridge zones are formed along their edges with second rising zones repeating rise and fall substantially in saw-tooth-shape transversely of the one direction.
(3) The fibrous assembly contains thermoplastic synthetic fibers or chemical fibers having a fineness of 0.05~15 deniers.
(4) The fibrous assembly is formed by any one of a thermal bond nonwoven fabric, a melt blown nonwoven fabric and a spun lace nonwoven fabric.
(5) The plastic sheet is formed with a plurality of tubular zones extending from the upper surface to the lower surface and each of the tubular zones has an opening diameter of 0.1~5 mm at the upper surface of the plastic sheet.
(6) Inside the tubular zones, the component fibers partially extend upward beyond top ends of the tubular zones.
REFERENCES:
patent: 4637819 (1987-01-01), Ouellette et al.
patent: 5891119 (1999-04-01), Ta et al.
patent: 6117524 (2000-09-01), Hisanaka et al.
patent: 0919212 (1999-06-01), None
patent: 62-57551 (1987-03-01), None
patent: 7-328061 (1995-12-01), None
Hisanaka Takayuki
Takai Hisashi
Yamaki Koichi
Chevalier Alicia
Lowe Hauptman & Gilman & Berner LLP
Uni-Charm Corporation
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