Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Including an additional nonwoven fabric
Reexamination Certificate
1998-06-08
2001-03-20
Krynski, William (Department: 1774)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Including an additional nonwoven fabric
C442S389000, C156S073100, C428S198000, C604S378000, C604S379000
Reexamination Certificate
active
06204210
ABSTRACT:
The present invention relates to a composite nonwoven material which, when used as a surface web or, in addition to the surface web, as a band in the crotch zone, above the absorbent pad in an absorbent hygienic article, such as diaper pants or an incontinence lining, makes it possible to improve the rate at which the urine passes through this nonwoven material in the direction of the absorbent pad, whilst limiting the backflow of urine towards the user's skin (rewetting), thus ensuring that the skin is better isolated from the absorbent pad of the hygienic article.
In general terms, absorbent hygienic articles, such as diaper pants and incontinence linings, comprise an outer layer or sheet made of material impermeable to body fluids, such as urine, and an inner layer or surface web permeable to body fluids, a pad or cushion of absorbent material being arranged between said layers.
The purpose of this surface web permeable to body fluids is to isolate the skin from the moistened absorbent pad. Consequently, the surface web must have a suitable degree of softness and must ensure that the urine passes through quickly in the direction of the absorbent pad, whilst forming an obstacle to the return of the urine towards the user's skin.
The document FR-A-2,588,285 describes a multilayer nonwoven textile having at least two nonwoven web layers, one of the layers being formed from fibers of bilobed cross section and the other layer being formed from fibers of trilobed cross section.
Each web layer is preferably obtained by means of the spunbonded technique and the two web layers are joined to form the multilayer nonwoven by thermal bonding in compacted and discontinuous zones.
The document WO 87/07117 describes an absorbent hygienic article comprising an absorbent body surrounded by a sheath. This sheath or surface web consists of two layers of nonwoven material. The first layer of nonwoven material, in contact with the user's skin, consists of a thin layer of spunbonded fibrous cloth and of a hydrophobic material, and the second layer, in contact with the absorbent body, is a hydrophobic fibrous layer of meltbonded fibrous cloth having a design similar to that of the first layer. These two surface web layers are not bonded to one another in the zone intended to come into contact with the user's body.
The document WO 88/05269 relates to a surface web for a disposable absorbent article, composed of at least two nonwoven layers which may be identical or different and which are joined by means of lines of adhesive forming an open pattern.
The document FR-A-2,698,385 describes a composite nonwoven material comprising at least one layer composed of a nonwoven permeable to body fluids and, on this first layer, a fiber lap of the carded type, permeable to body fluids, the fiber lap of the carded type being bonded to the first layer by needling. This composite nonwoven material can be used as a surface web in an absorbent hygienic article. An object of the present invention is, therefore, to provide a composite nonwoven material having a desired degree of softness as well as an improved rate of passage of liquids and improved rewetting resistance, as compared with the prior nonwovens described above and used hitherto to form the surface webs of absorbent hygienic articles. Another object of the present invention is to provide an absorbent hygienic article, such as diaper pants and incontinence linings, comprising preferably a surface web formed from such a composite nonwoven material, the cost of manufacturing said article being reduced due to the characteristics of said composite nonwoven material. Yet another object of the present invention is to provide a method for manufacturing such a composite nonwoven material. According to the present invention, a composite nonwoven material is produced, comprising two outer layers of a nonwoven permeable to body fluids, a synthetic fiber lap permeable to body fluids being arranged between said layers, characterized in that at least the outer layers are assembled together by hot melting according to a pattern forming a network of spots, and in that they comprise, furthermore, a perforated central zone. Advantageously, the two outer nonwoven layers consist of natural or synthetic textile fibers selected from cellulose, viscose, polyester, polyethylene, polypropylene, nylon or ethylene/propylene copolymer fibers.
Also advantageously, the intermediate lap is of the carded type or of the type with nonbonded continuous filaments, said lap consisting of synthetic textile fibers of polyester, polyethylene, polypropylene, nylon or ethylene/propylene copolymers.
The outer layers and the intermediate lap may advantageously have respectively a weight per unit area of between 5 and 15 m/m
2
for the layers and between 5 and 30 g/m
2
for the lap. Moreover, the upper outer nonwoven layer comprises a hydrophilic longitudinal central zone delimited by continuous weld lines made between at least the two outer layers and forming barriers to the transverse diffusion of body fluids.
Another subject of the present invention is an absorbent hygienic article, such as diaper pants, which comprises an outer layer impermeable to body fluids, an absorbent pad permeable to body fluids, which is secured to this outer layer, and a surface web permeable to body fluids, covering the absorbent pad and secured to the outer layer, the surface web consisting of the abovedescribed composite material according to the invention, the upper outer nonwoven layer provided with a hydrophilic central zone forming the layer intended to be first in contact with the body fluids and therefore the body of the user.
The invention also relates to an absorbent hygienic article comprising an outer layer impermeable to body fluids, an absorbent pad permeable to body fluids and secured to the outer layer, and comprising two widened opposite end parts and a narrower crotch zone, a crotch zone band permeable to body fluids, of a width similar to the crotch zone of the pad and of a length similar to the pad, and a surface web permeable to body fluids and secured to the outer layer, the crotch zone band consisting of the composite nonwoven material according to the invention, the upper outer nonwoven layer provided with a hydrophilic central zone being oriented so as to be in contact with the body fluids first or immediately after the surface web.
Advantageously, the crotch zone band is arranged between the absorbent pad and the surface web.
The invention also provides a method for manufacturing a composite nonwoven material, which comprises the steps involving:
unwinding simultaneously a synthetic fiber lap permeable to body fluids and two nonwoven laps permeable to body fluids,
inserting the synthetic fiber lap between the two nonwoven laps,
feeding the assembly as a whole to a calendering device, allowing uniform spot bonding between at least the nonwoven laps by hot melting,
feeding the composite band obtained through a perforation device in order to obtain a perforated central zone.
Advantageously, the method comprises the step involving feeding the composite band to a welding device, making it possible to produce, on the one hand, a first pair of continuous weld lines symmetrical to the longitudinal center axis of the band, between at least the two nonwoven laps, in the vicinity of each longitudinal edge of said band, and, on the other hand, a second pair of continuous weld lines which are also symmetrical to the longitudinal center axis of the band and the transverse spacing of which is smaller than that of the first pair and which thus delimits a hydrophilic longitudinal central zone on the upper face of said composite nonwoven material.
Advantageously, the calendering, perforation and welding devices may be of the ultrasonic type.
REFERENCES:
patent: 5257982 (1993-11-01), Cohen et al.
patent: 5556392 (1996-09-01), Koczab
patent: 5704101 (1998-01-01), Majors et al.
patent: 5851204 (1998-12-01), Mizutani
patent: 0 072 948 A1 (1983-03-01), None
patent: 0 241 041 A2 (1987-10-01), N
Avgol, Ltd.
Burns Doane Swecker & Mathis L.L.P.
Gray J. M.
Krynski William
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