JPH0671472B2 - Absorbent article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to reinforced batting or panels for disposable absorbent articles, such as disposable diapers. More specifically,
The present invention relates to a multi-layered batting which includes a liquid-permeable reinforcing sheet between two battings.

Disposable diapers offer considerable advantages and conveniences compared to diapers that are to be washed and reused,
In recent years these disposable diapers have had great success in the market. A typical disposable diaper structure comprises a moisture retaining layer having a relatively high liquid retention capacity sandwiched between a moisture permeable surface layer and a moisture impermeable plastic backing sheet, and It is to be confined in the holding layer. This type of diaper is shown in US Pat. No. 3,612,055 (Mesek et al) and US Reissue Pat. No. 26,151 (Duncan et al).

The water-retaining layers of conventional diapers have typically been comprised of a batting of loosely compressed cellulosic fibers. It is well known to provide absorbent batting of this type with an integrally formed compressed paper-like layer or skin and is disclosed in U.S. Pat. Nos. 3,017,304 (Burgeni) and 3,612,055 (M
esek et al) has a typical structure of this kind. It is also known to provide absorbent batting with vertically extending thick compressed areas that direct moisture along the length of the batting, along with a continuously compressed paper-like layer or skin. No. 3,938,522 (Repke) is representative of this type of structure.

In addition to providing a wicking mechanism that initially directs the liquid away from the wetted area to the remote areas of the diaper, this type of compressed layer and area provides stability and strength to the wadding. It was Despite this beneficial effect, lack of adequate panel stability has long been a challenge in the field of disposable absorbent articles, and this remains to be resolved.

To solve this problem, the prior art concentrates and reinforces a water-impermeable film or sheet assembly in or adjacent to an absorbent batting, and provides an opening in this type of sheet to provide liquid Allowed them to pass through it. Although this type of sheet or film contributed to the improved batting stability, they did so at the expense of the absorbent properties of the batting, and this type of film or sheet was actually used in or within the batting. Forming a liquid barrier adjacent to. U.S. Pat.No. 3,645,060 (Goldma
n), No. 3,890,974 (Kozak), No. 4,014,341 (Karam
i) and 4,282,874 (Mesek) are representative of this type of prior art disclosure.

Clearly, it would be desirable to provide absorbent articles, such as reinforced wadding for disposable diapers, without compromising their ability to absorb wet liquids.

According to the present invention, the moisture-permeable reinforcing sheet is incorporated in the absorbent pad and not only imparts strength and stability to the pad, but also contributes to wicking in the pad, but It does not interfere with the ability of the wadding to absorb liquids that have been absorbed. More specifically, the batting of the present invention comprises a pair of batting layers with a moisture permeable fabric reinforcing sheet disposed therebetween.

Stability is imparted to each batting layer adjacent to the reinforcing sheet. It is due to the frictional engagement between the fibers. In essence, the stiffening sheet acts as a locking or retracting means, which prevents the batting layer from moving relative to the stiffening sheet and to each other.

The reinforcing sheet is preferably a non-woven fabric formed of polyester or the like, which sheet may normally have the same extent of outer dimensions as the batting layer and is arranged between the layers. The stuffing layer is considerably coarser than the reinforcing sheet and will preferentially wick the liquid that wets the absorbent stuffing along the reinforcing sheet. Being permeable to liquids, the reinforcing sheet exhibits virtually no hindrance with respect to the rate or amount of liquid absorption in the cot. In fact, the reinforcing sheet imparts strength and stability to the batting, so that the use of a heavier batting layer can provide enhanced liquid storage capacity.

According to another aspect of the invention, expansion means are provided inside the reinforcing sheet to accommodate flexing and stretching of the facing, backing and batting layers and to associate them with the reinforcing sheet.
More specifically, a slit pattern is provided at the center of the reinforcing sheet, which allows the reinforcing sheet to expand with respect to elongation, forming a grid-like shape without tearing or breaking the reinforcing sheet. It is a thing. Upon contraction, the reinforcing sheet contracts and assumes its original non-expanded form. These slits are partially open to accommodate certain shrinkages that may occur during the manufacturing process of the diaper as it is manufactured.

While the invention is susceptible to embodiments in many different forms, the preferred drawings are set forth in detail in the accompanying drawings and the specification, and the disclosure is illustrative of the principles of the invention. Furthermore, it is to be understood that there is no intent to limit the invention to the embodiments shown.
The scope of the invention is set forth in the claims.

Referring to the accompanying drawings, the disposable diaper 10 of the present invention includes a facing 12 formed from a moisture permeable material and is adapted to be positioned adjacent to the infant's skin. The diaper 10 further comprises a moisture impermeable outer layer 16 which is substantially coextensive with the facing 12 in outer dimensions. Outer layers 12 and 16
Sandwiched between is an absorbent unit 14, which is smaller in outer dimensions than outer layers 12 and 16,
Further, they are arranged symmetrically with respect to them. As is well understood by those skilled in the art, the absorbent unit 14 may be secured to the backing sheet 16 by spaced parallel adhesive layers, and the layers 12 and 16 may also be padded, for example by an adhesive layer.
They may be fixed to each other on the outside of 14.

Further, as known to those skilled in the art, fastening means are provided for releasably attaching the diaper 10 around the perineum of the wearer, and such fastening means are tape tabs secured to one end of the backing sheet 16. It may take 18 forms.

The absorbent unit 14 includes first to lower batting layers 20 which are arranged face-to-face in parallel with the backing sheet 16,
It is also fixed to it by the adhesive layer described above. Padded layer 20
May include an integral paper-like compression skin on its lower surface as taught by US Pat. No. 3,612,055 (Mesek et al), and a skin of this type is disclosed in US Pat.
It may be thickened in selected areas as taught by Repke.

The absorbent unit 14 is provided with an intermediate layer in the form of a reinforcing sheet 24, which is approximately coextensive with the filling surface layer 20 in the outer dimensions as shown and, in contrast, in a face-to-face juxtaposition thereto. It is arranged. The reinforcing sheet 24 does not have to be coextensive with the surface material and the backing layer in the outer dimensions,
Therefore, they may be shorter or slightly longer than these layers. However, what is important is that, as will be shown below, the reinforcing sheet, and especially its expansion means, be present in the central part of the diaper.

The sheet 24 is a non-woven fabric, and the fibers on the lower surface thereof and the fibers on the upper surface of the batting layer 20 cooperate by inter-fiber frictional engagement to lock the reinforcing sheet 24 in place against the batting layer 20. The reinforcing sheet 24 is made of polyester non-woven fabric (spun-bond).
A liquid-permeable cloth such as ed polyester fabric).
Although the weight of the fibers is not critical to the present invention, a polyester nonwoven having a fiber weight of about 0.7 oz / yd ² (about 23.7 g / m ² ) should be satisfactory for the purposes of the present invention. Have been found. The reinforcing sheet may be made of other polymeric materials, such as polyethylene, as long as that type of sheet is water absorbent. As used herein, the term "moisture permeable" refers to fibers that do not substantially impede the permeation of moisture from the batting layer 22 through the moisture permeable reinforcing sheet into the underlying batting layer. The reinforcing sheet preferably has a greater density than the adjacent batting layer to provide a wicking mechanism within the absorbent unit.

The absorbent unit 14 includes a second cotton layer 22 disposed in superposed relationship with a reinforcing sheet 24. Cotton pad 22
Has substantially the same outer dimensions as the padding layer 20 and the reinforcing sheet 24,
Then, it is substantially adjacent to the reinforcing sheet 24. Stuffed cotton 22
Are held against movement relative to the reinforcing sheet 24 and thus to the batting layer 20 by virtue of the co-operation of the interfiber frictional engagement at the adjacent surfaces of the batting layer 22 and the reinforcing sheet 24.

Several different types of materials can also be used for surface layer 12. For example, as described in U.S. Pat.No. 3,663,348, the material may be a non-woven web composed of a mixture of fibers, the mixture being predominantly inexpensive, short cellulosic fibers in an amount of 75 percent to 98 percent. , For example short wood pulp fibers or Kotton linters and the rest consisting of textile length fibers, for example rayon.

A non-woven material suitable for use in forming the surface material layer of the diaper according to the present invention has a cloth weight of about 0.5-5 oz / yd ² (about 17-170 g /
m ² ) and density less than 0.15 g / cc, generally
Within the range of 0.05 to about 0.1 g / cc, about 1.5 oz / yd ² (about 50
The dry strength of a fabric material having a weight of g / m ² ) is at least 0.15 lb per inch width in the machine direction and at least 0.1 lb per inch width in the cross direction.
1.8 g / cm). Such fabrics have good elongation, loft, softness and drape properties.

The surfacing material may also be prepared from an apertured non-woven fabric, which is described, for example, in US Pat.
It is formed according to the teachings of 1,514 and 3,081,515. Further, the surface material is, for example, U.S. Pat. No. 3,485,70.
It can also be prepared from other types of fabrics disclosed and described in No. 6 (Evans). This type of facing material can be prepared from natural fibers, synthetic fibers or blends thereof. A typical diaper surfacing prepared from polyester type fibers has a weight of about 0.75 oz / yd ² (25.4 g / m ² ).

The facing may be the same size and coextensive with the backing, or the facing may be wider than the backing and have its side edges folded inward, so that The facing will be coextensive with the backing, as shown in FIG. 3 of US Pat. No. 3,612,055. In addition, the facing may be prepared from non-porous materials such as non-woven isotropic webs or polyolefin or polyester films with apertures having the desired moisture permeability. In all of the above facing materials, the material should be relatively hydrophobic to prevent wicking in the facing material.

A suitable material for the diaper backing 16 of the present invention is an opaque polyolefin, such as about 0.001 inch (0.00254 inch).
cm) thick polyethylene. Another suitable material for this purpose is about 0.005 inch thick polyethylene terephthalate.

The batting layers 20 and 22 are loosely compressed short cellulosic fibers, such as wood pulp fibers or Kotton linters,
Alternatively, formed from a mixture thereof, they are held together by an interfiber bond without the addition of adhesives, as is known in the art. In summary, these batting layers are low bulk density coherent webs of loosely compressed cellulosic fibers, preferably comminuted pulp fibers in the form of so-called "fluff".

As used herein, the term "short fiber" has a length of about 1/4.
Longer than an inch (about 0.64 cm), usually 1/2 to 21/2 in length
Refers to a length of less than about 1/4 inch with respect to "long fibers" or "cloth length fibers" of inch (about 1.27 to 6.35 cm).

The bottling layers 20 and 22 may be formed as separate layers and then positioned in relation to each other and also to the reinforcing sheet 24 in the above relationship. Alternatively, the stuffing layer 22 can be formed by directly disposing it on the reinforcing sheet 24. In either case, the resulting composite laminate can be lightly compressed to enhance interfiber frictional engagement between the fibers of the reinforcing sheet 24 and the fibers on the contact surfaces of the swatch layers 20 and 22. .

The reinforcing sheet 24 is provided with an expansion means 26 in its central portion,
It is adapted to accommodate the expansion and contraction of backing, facing and batting layers that occur during application and wearing of the diaper 10. The expansion means 26 comprises an open end 28 and
It is provided in the center of the reinforcing sheet between 30. Expansion means
26 is formed by a plurality or parallel rows of elongated slits 32, which are arranged at right angles to the sides of the reinforcing sheet. When the diaper is first manufactured, the reinforcing sheet 24 is pulled to partially release the slit 32. This accommodates shrinkage or shrinkage of the reinforcing sheet that may occur due to heat and / or moisture during subsequent manufacturing steps.

As is apparent from FIG. 4, the slits 32 in adjacent rows are located in a zigzag, overlapping relationship with each other. As a result, when the reinforcing sheet is expanded, the expansion means
26 will typically form an open grid-like structure that forms rhomboid openings 34. The non-slit cloth portion between the openings 34 provides a number of hinges which allow the sheet to flex and follow the movement of the facing, backing and batting layers. The expansion of the seat 24 takes place without it tearing or breaking, so that the seat continues to perform its reinforcing action. When the expansion force (indicated by directional arrow F in FIG. 5) is released, the stiffening sheet contracts back to its initial non-expanded position shown in FIG. 4, where the slit is fully expanded as shown in FIG. About the size of the opening 34
25% open.

Although the disposable diaper 10 shown in the accompanying drawings does not include elastic elements at its opposite ends, it is well known that such diapers provide improved fit and seal around infant legs. is there. Reinforcing panels with expansion means according to the invention are particularly suitable for use in so-called "fit diapers" of this kind. In use, the disposable diaper is applied to the baby by placing it on a single, flat surface and laying the baby on it. The underlying end of the diaper is the end provided for the fastener means and the other end of the diaper extends downward between the infant's legs. The diaper's downwardly extending edge is then brought between the infant's legs to cover the perineum and be positioned so as to be continuous with the infant's waist front. Then, place the waist corner of the abdominal covering end as long as it wraps around the baby's waist, and make the end corner lying under the diaper into a superposed relationship with the previously mentioned corner. The diaper adheres to the infant so that it tightly surrounds the infant's waist and provides a natural fit. The adhesive tape fasteners to be used are then prepared and the diaper is secured in the desired position by simply contacting the pressure sensitive adhesive side of the tape tab with the adjacent outer surface of the opposing corner of the diaper.

[Brief description of drawings]

FIG. 1 shows a disposable diaper formed in accordance with the teachings of the present invention, with a partial cutaway perspective view showing details of its internal structure, and FIG. 2 taken along line 2-2 of FIG. FIG. 3 is a perspective view showing the diaper of the present invention applied to an infant, and FIGS. 4 and 5 are enlarged fracture views showing the non-expanded and expanded states of the reinforcing sheet of the present invention, respectively. It is a top view. 10 is a diaper, 12 is a surface material, 16 is an outer layer, 20 is the first cotton layer,
22 is a cotton layer, 24 is a reinforcing sheet, 26 is expansion means, 32 is an elongated slit, and 34 is a rhombic opening.

Claims (8)

[Claims] 1. A first outer layer which is a water-impermeable backing sheet, and a multi-layer absorbent which is smaller than the first outer layer and is spaced inward from each side edge of the first outer layer. A second layer which is a means for padding, the second layer comprising a first cellulosic fiber wadding disposed overlaid on the first outer layer and the first layer.
And a second cellulosic fiber stuffing arranged to be superposed on the moisture permeable reinforcing sheet. The sheet is an absorbent article that includes a second layer composed of a nonwoven fabric that includes elastically expandable opening means and a third layer that is a moisture permeable topsheet that is overlaid on the second layer. . 2. The elastically expandable opening means includes a staggered array of elastically expandable openings extending across opposite edges of the expandable nonwoven sheet. The disposable diaper described in the item. 3. The plurality of elastically expandable openings comprises:
The disposable diaper according to claim 2, comprising uniform slits extending in the side edge direction of the moisture-permeable reinforcing sheet. 4. The disposable diaper, wherein the absorbent article is substantially rectangular, and comprises a water-impermeable backing sheet and a water-permeable top sheet having the same shape and area, and the pad means is substantially The method of claim 1, wherein the method is rectangular and is disposed substantially symmetrically with respect to the moisture impermeable backing sheet and the moisture permeable topsheet. 5. A first outer layer in the form of a water-impermeable backing sheet, which is arranged in a superposed relationship with the backing sheet and is smaller than the backing sheet, that is, spaced from its longitudinal side edges inwardly. Of the expandable moisture permeable sheet means disposed in a face-to-face relationship with the first absorbent batting that has a second layer and is opposite the backing sheet to the first batting layer. A third layer of the form and a second absorbent batting fourth layer that is placed in a face-to-face relationship with the expandable sheet means layer opposite the batting of the second layer; An expandable sheet means comprising a fifth layer in the form of a sheet of moisture permeable facing material, opposite the sheet means, superimposed on a fourth layer of the second cot and arranged in a facing relationship. The layer usually has the same dimensions as the first cotton layer and the fourth layer The second batting typically has the same dimensions as the expandable sheet means, and the facing sheet has the same dimensions as the moisture impermeable backing sheet, thereby providing an edge around the circumference of the diaper, Among them, a substantially rectangular multilayer disposable diaper characterized in that a backing sheet and a surface material sheet are in contact with each other and are fixed. 6. The disposable diaper according to claim 5, wherein the expandable sheet means includes a non-woven fabric having an elastically expandable opening means provided in the longitudinal center thereof. 7. The elastically expandable opening means includes a staggered array of elastically expandable openings extending across opposite edges of the expandable nonwoven sheet. The disposable diaper described in the item. 8. The disposable diaper according to claim 7, wherein the elastically expandable opening includes a slit extending in a side edge direction of the expandable nonwoven sheet.