Absorbent article and method of manufacturing the absorbent article

An absorbent article according to the present invention includes: a water-decomposable top sheet, a water-decomposable back sheet; and a water-decomposable absorber placed between the top sheet and the back sheet. The back sheet is formed of multiple sheet pieces each being smaller than a main body of the absorbent article, and each sheet piece at least partially overlapping adjacent one or more of the other sheet pieces. In addition, an adhesive is applied to each overlapping region where adjacent two of the sheet pieces overlap each other.

TECHNICAL FIELD

The present invention relates to an absorbent article including: a water-decomposable top sheet, a water-decomposable back sheet; and a water-decomposable absorber placed between the top sheet and the back sheet, and to a method of manufacturing such an absorbent article.

BACKGROUND ART

Heretofore, as shown in Japanese Patent Literature #1, an absorbent article has been known in which a fastening piece for fastening the absorbent article to an undergarment is formed to protrude from both lateral sides of the main body.

When putting on the absorbent article, a wearer fastens the absorbent article to his/her undergarment by winding the fastening piece around the crotch of the undergarment.

In addition, in that absorbent article, the fastening piece is provided with a frangible portion for making the fastening piece easy to break, in order to facilitate removal of the absorbent article from the undergarment after use. Further, the absorbent article is formed by water-decomposable materials so that the absorbent article can be dispersible at a higher speed in a drainage pipe or in a septic tank.

However, the foregoing absorbent article relies solely on the fastening piece as means for fastening the absorbent article to an undergarment. Moreover, a region where the absorbent article is attached to the undergarment is located on a surface of the crotch of the undergarment to be in contact with wearer's clothes. Hence, the absorbent article has a problem that the absorbent article is liable to be separated away from the crotch as the wearer moves, and thus to be displaced from the undergarment.

In addition, since it is designed to be fastened by turning the fastening piece around the crotch of the undergarment, the foregoing absorbent article has a problem that the fastening piece might be brushed between the wearer' s groin and the crotch while the wearer is walking, which damages the frangible portion, and consequently makes the wearer feel uncomfortable.

CITATION LIST

Patent Literatures

SUMMARY OF THE INVENTION

The present invention has therefore been made in consideration of the foregoing problems, and the present invention seeks to provide an absorbent article that has an improved fastening capability to an undergarment, and that is dispersible at a higher speed in a drainage pipe or in a septic tank, and to provide a method of manufacturing such an absorbent article.

A first aspect of the present invention is summarized as an absorbent article including: a water-decomposable top sheet; a water-decomposable back sheet; and a water-decomposable absorber placed between the top sheet and the back sheet. In addition, in the absorbent article, the back sheet is formed of multiple sheet pieces each being smaller in size than a main body of the absorbent article, and each sheet piece at least partially overlaps with adjacent one or more of the sheet pieces, and an adhesive is applied to each overlapping region where adjacent two of the sheet pieces overlap each other.

A second aspect of the present invention is summarized as a method of manufacturing an absorbent article that includes: a water-decomposable top sheet; a water-decomposable back sheet; and a water-decomposable absorber placed between the top sheet and the back sheet. Specifically, the method of manufacturing an absorbent article includes the steps of: continuously conveying multiple continua of back sheets on aback sheet line; placing the continua of back sheets to extend in a moving direction of the back sheet line so that each continuum of back sheets can at least partially overlap adjacent one or more of the continua of back sheets; and applying an adhesive to each overlapping region where adjacent two of the continua of back sheets overlap each other.

As has been described above, the present invention can provide an absorbent article that has an improved fastening capability to an undergarment, and that can be dispersed at a higher speed in a drainage pipe or in a septic tank, and can provide a method of manufacturing such an absorbent article.

DESCRIPTION OF THE EMBODIMENT

(Structure of Absorbent Article According to a First Embodiment)

Hereinafter, description will be given of a structure of an absorbent article according to a first embodiment of the present invention with reference toFIGS. 1 to 5.FIG. 1is a perspective view of an absorbent article1according to this embodiment viewed from the top surface thereof (from a surface to be in contact with a wearer's skin).

Note that, in this embodiment, a party-liner is described as a representative example of the absorbent article1according to the present invention. However, the present invention is not limited to this, but is applicable to an incontinence pad, a diaper, a sanitary napkin or the like.

As shown inFIG. 2, the absorbent article1has a water-decomposable top sheet2, a water-decomposable back sheet3and a water-decomposable absorber4placed between the top sheet2and the back sheet3.

A peeling paper6for maintaining adhesive properties of an adhesive5is provided on the back side of the absorbent article1, or more specifically, on the back side (a surface to be in contact with the wearer's undergarment) of the back sheet3. When putting on the absorbent article1, the wearer exposes the adhesive5on the back side of the back sheet3by peeling off the peeling paper6, and then attaches the absorbent article1to the crotch of his/her undergarment by bonding the absorbent article1thereto with the adhesive5thus exposed.

In addition, a waterproof paper7is provided between the absorber4and the back sheet3, in this embodiment. Note that the waterproof paper7need not necessarily be provided. Accordingly, the waterproof paper7maybe appropriately provided in accordance with a performance required for the absorbent article1.

The top sheet2and the absorber4are joined together with a water-soluble adhesive10a, the absorber4and the waterproof paper7(the back sheet3, instead, in the case where the waterproof paper7is not provided) are joined together with a water-soluble adhesive10b.

The top sheet2is liquid permeable, hydrophilic and non-irritating to the wearer's skin. The top sheet2may be made solely of a water-decomposable non-woven fabric, or made of a composite material including a water-decomposable non-woven fabric.

While the wearer wears the absorbent article1, the top sheet2might brush against the wearer's skin. This causes fibers of the top sheet2to fall out, and might eventually cause the top sheet2to wear out. To prevent this, the top sheet2may be alternatively made of a material based mainly on cellulose fibers, which are hydrophilic and, if contained in a sheet, increase the surface strength thereof.

Specifically, the top sheet2may be made of a wet spunlaced non-woven fabric having a fiber length in the 1 mm to 20 mm range formed as follows. A fiber blend containing 80 to 100 mass % hydrophilic fibers and 0 to 20 mass % fine-diameter hydrophobic fibers is dispersed at an area density not less than 20 g/m2but not more than 50 g/m2. After that, these constituent fibers are entangled with one another by hydro-entanglement and then dried. Lastly, in this example, the obtained web is adjusted to have a thickness of not less than 0.3 mm but not more than 1.0 mm.

For example, the top sheet2may be made of a wet spunlaced non-woven fabric whose mass per unit area is adjusted to 40 g/m2.

This non-woven fabric may contain unbeaten pulp (for example, 30 mass %), split microfibers (for example, 20 mass %), and rayon, preferably having a fineness of 1.1 dtex and preferably having a fiber length of 9 mm.

The absorber4is made of a liquid-retainable material such as water-decomposable non-woven fabric, water-decomposable air-laid pulp or water-decomposable paper.

For example, the absorber4may be made water-decomposable air-laid pulp. This pulp may have a mass per unit area which is adjusted to 70 g/m2, and may contain pulp (for example, 80 mass %) and a water-decomposable binder (for example, 20 mass %).

The back sheet3is designed to be broken into pieces and dispersed by the flow and pressure of water in a flush toilet or a septic tank when flushed in a toilet.

The back sheet3is made of a material such as a water-decomposable non-woven fabric or a water-decomposable paper containing water-dispersible fibers. In the present embodiment, the back sheet3is divided into4pieces in the width direction of the absorbent article1. Each of the divided sheet pieces of the back sheet3overlaps with each other at least partially. Further, an adhesive5is applied to the overlapping regions.

(Structure of Absorbent Article According to a Second Embodiment)

Hereinafter, description will be given of a structure of an absorbent article according to a second embodiment of the present invention. Hereinbelow, description will be given mainly on the portions different from the absorbent article1of the aforementioned first embodiment. Main differences on the absorbent article1between the first embodiment and the second embodiment is on the structure of the back sheet3and the regions to which the adhesive5are applied. As shown inFIG. 3, the back sheet3consists of multiple sheet pieces3A to3C each smaller than the main body of the absorbent article1.

Each of the sheet pieces3A to3C at least partially overlaps adjacent one or more of the sheet pieces3A to3C. For example, the sheet pieces3A and3B may overlap each other, and the sheet pieces3B and3C may overlap each other, as shown inFIGS. 4 and 5. Note thatFIGS. 4 and 5are each a cross-sectional view of the absorbent article1taken along the B-B′ line inFIG. 3. In the cross-sectional view shown inFIGS. 4 and 5, multiple sheet pieces3A to3C overlap in different manners. In the absorbent article1according to the present embodiment, any one of the overlapping shown inFIGS. 4 and 5is applied.

The adhesive5is applied to each overlapping region where adjacent two of the sheet pieces3A to3C overlap each other. For example, as shown inFIGS. 4 and 5, the adhesive5is applied to an overlapping region30xwhere the sheet pieces3A and3B overlap each other, as well as to an overlapping region30ywhere the sheet pieces3B and3C overlap each other.

In the example shown inFIGS. 3 to 5, the overlapping regions30xand30yare arranged to extend in the longitudinal direction of the absorbent article1. The overlapping regions30xand30yare portions in which a part of multiple sheet pieces overlapping with the adjacent sheet piece each other. It is preferable that the peripheral portions of each sheet pieces overlaps so as to form the overlapping portions30xand30y,as shown inFIGS. 4 and 5.

Specifically, it is preferable that at least 5% of the planar area of the sheet piece overlaps with the adjacent sheet piece so as to form the overlapping portions30xand30y. It is more preferable that at least 10% of the planar area of the sheet piece overlaps with the adjacent sheet piece. Further, it is preferable that the overlapping portions30xand30ybe set not more than 50% of the planar area of the sheet piece. It is more preferably that the overlapping portions30xand30ybe set not more than 25% of the planar area of the sheet piece. Note that, a part of the sheet pieces need not necessarily overlap to form the overlapping portions30xand30y. Alternatively, for example, whole portion of the certain sheet piece may be formed to overlap with a part of other sheet piece. In other words, preferable range of the overlapping portions30xand30yis 10% to 25% of the planar area of the sheet piece.

In the sheet pieces3A to3C, regions not coated with the adhesive5serve as entrances through which water enters the inside of the absorbent article1when the absorbent article1is disposed of in a flush toilet after use, and thus put into water.

In addition, each of the sheet pieces3A to3C may be not more than 50 mm in length and width, or preferably be not more than 30 mm in length and width, so as not to entangle around a diffuser in a septic tank.

Having a size small enough to readily sink in a settlement tank in a septic tank as described above, the sheet pieces3A to3C may be made of a non-water-decomposable material. In other words, there is no problem even if the sheet pieces3A to3C are made of a non-water-decomposable material, since the sheet pieces3A to3C can flow to a settlement tank and sink therein, and will be collected when the settlement tank is cleaned.

The sheet pieces3A to3C may be contiguously connected, or more specifically, the sheet pieces3A to3C may be caused to partially overlap and the adhesive5may be applied to the overlapping regions, by the following method for example. For example, three sheet pieces3A to3C in total each being approximately 100 mm in length and approximately 20 mm in width are arranged in one line in the longitudinal direction and three lines in the width direction so as to partially overlap. Then, the sheet pieces3A to3C are joined together and the adhesive5in a pattern of circles is applied to the overlapping portions.

In addition, the back sheet3(sheet pieces3A to3C) is made of a water-decomposable non-woven fabric or a water-decomposable paper, for example.

Specifically, the back sheet3(the sheet pieces3A to3C) may be made of a material including: (1) a water-decomposable non-woven fabric formed by entangling water-dispersible fibers each having a relatively small fiber length with one another by the flow of water; (2) a water-decomposable paper shaped into a sheet, which is formed by water-dispersible fibers, such as pulp and rayon, blended with a water-soluble binder for binding the fibers; (3) a water-decomposable paper formed by shaping pulp into a sheet by utilizing hydrogen bonding among the constituent pulp fibers; (4) a water-decomposable paper formed by entangling water-dispersible fibers with one another and then by shaping the entangled fibers into a sheet; or the like. In addition, in order to make the back sheet3impermeable to liquid, the surface thereof may be treated with a water repellant finish by applying a biodegradable resin, such as polylactate or polyvinyl alcohol, to the surface.

Specifically, the back sheet3(the sheet pieces3A to3C) may be made of a wet spunlaced non-woven fabric, which may have a fiber length in the 1 mm to 20 mm range formed as follows. Fiber blend containing pulp fibers (for example, 30 to 70 mass %) and rayon fibers (for example, 30 to 70 mass %) is dispersed at an area density in the 20 g/m2to 50 g/m2range. After that, these constituent fibers are entangled with one another by hydro-entanglement and then dried. Lastly, the obtained web is adjusted to have a thickness which is preferably in the range of 0.1 mm to 1.0 mm range.

For example, the back sheet3(the sheet pieces3A to3C) is made of a wet spunlaced non-woven fabric whose mass per unit area is adjusted to 40 g/m2. This non-woven fabric may contain beaten pulp (for example, 30%), unbeaten pulp (for example, 20%), and rayon preferably having a fineness of 1.1 dtex and a fiber length of 7 mm.

Note that, as shown inFIGS. 4 and 5, in each overlapping regions30xand30ywhere adjacent two of the sheet pieces3A to3C overlap each other, the adhesive5is applied so as to be exposed to both the side of the waterproof paper7(that is, the absorber4side) and the side of the peeling paper6. This allows a wearer to bond the absorbent article1to the undergarment with the adhesive5used for joining the sheet pieces3A to3C when he/she attaches the absorbent article1to his/her undergarment.

In addition, the adhesive5is discontinuously applied to each of the overlapping regions30xand30y. Specifically, the adhesive5is applied in a pattern, which is discontinuously arranged at certain intervals; for example, a pattern in which repeated circles as shown inFIG. 3or repeated rectangles are arranged at certain intervals.

In other words, the adhesive5is applied to multiple areas spaced apart from one another in the back sheet3so as to join the sheet piece3A to3C together and to be exposed on the surface of the back sheet3to be in contact with a wearer's undergarment.

The adhesive5may be applied in a pattern as described above by a method such as slot coating, spray coating, porous coating, using a roll coater, and gravure coating. Among these, a coating method using a roll coater is preferable, since it enables a pattern design of adhesive having certain intervals.

A coating amount of the adhesive5for each pattern is preferably within the 10 g/m2to 250 g/m2range, and is most preferably within the 50 g/m2to 150 g/m2range.

If the coating amount of the adhesive5for each pattern is not more than 50 g/m2, adhesion strength between the absorbent article1and a wearer's undergarment tends to be too reduced. Because, most of the adhesive5is absorbed by and retained within the back sheet3(sheet pieces3A to3C) in this case, and thus only a small amount of the adhesive5is exposed on the surface of the back sheet3to be in contact with the undergarment.

On the other hand, if the coating amount of the adhesive5for each pattern is not less than 150 g/m2, adhesion strength between the absorbent article1and a wearer s undergarment tends to be too increased. Because, a large amount of the adhesive5is left unabsorbed by and thus not retained within the back sheet3(sheet pieces3A to3C), and consequently exposed on the surface of the back sheet3to be in contact with the undergarment. The too-increased adhesion strength is likely to cause so-called material breakage, a phenomenon where the back sheet3and the absorber4are broken and thus partly left unpeeled from the undergarment when the absorbent article1is peeled off from the undergarment.

Each shape in the pattern of the adhesive5is smaller than the sheet pieces3A to3C, and should preferably have a size in the order of 1 mm to 10 mm. The shape in the pattern of the adhesive5may be a circle having a diameter from 1 mm to 10 mm, a quadrangle whose side lengths are from 1 mm to 10 mm, or the like. The shape in the pattern of the adhesive5may be a circle, an ellipse, a gourd-like shape, a square, a rectangle, a drop-like shape or the like.

Note that, after the back sheet3is decomposed in water, coated region50aand50b, which are coated with the adhesive5(seeFIGS. 4 and 5), might be connected to one another with the constituent fibers. To try to prevent this, in the back sheet3, the width of a non-coated region50c, which is not coated with the adhesive5, is preferably greater than the length (fiber length) of the fibers forming the non-woven fabric used as the back sheet3(the sheet pieces3A to3C). In the present embodiment, directions of the fibers forming the non-woven fabric are arranged along the longitudinal direction of the absorbent article1. It should be noted, however, the directions of the fibers forming the non-woven fabric are not necessarily arranged along the longitudinal direction of the absorbent article1.

The coated regions50aand50bmay be scattered at random all over the back sheet3. Alternatively, the coated regions50aand50bmay be regularly arranged in the longitudinal and/or width and/or oblique directions.

A pressure-sensitive adhesive or a thermal-sensitive adhesive may be used as the adhesive5. Here, the pressure-sensitive adhesive is mainly based on a synthetic rubber such as a styrene-ethylene-butadiene-styrene block copolymer (SEBS), a styrene-butadiene-styrene block copolymer (SBS) or styrene-isoprene-styrene block copolymer (SIS), while the thermal-sensitive adhesive is mainly based on a synthetic rubber such as EVA. A biodegradable adhesive or a water-soluble adhesive may also be used as adhesive5.

Note that, even when using any of the types of adhesive5described above, the back sheet3can be broken into pieces by the force of the flow of water entering through the non-coated region50cwith which the adhesive5is not coated.

The coated regions50aand50bare provided to continuously extend from one surface3xof the back sheet3(sheet pieces3A to3C) to the other surface3y.

Specifically, as shown inFIGS. 4 and 5, the coated regions50aand50bare provided to penetrate in the thickness direction from the surface3x(one surface) of the back sheet3(the sheet pieces3A to3C) facing the waterproof paper7(the absorber4side) to the surface3y(the other surface) of the back sheet3(the sheet pieces3A to3C) facing the peeling paper6.

In other words, the coated regions50aand50bare formed to penetrate across: the surface3xof the back sheet3(the sheet pieces3A to3C) that faces the waterproof paper7(the absorber4side); the inside of the back sheet3(the sheet pieces3A to3C); and the surface3yof the back sheet3(the sheet pieces3A to3C) that faces the peeling paper6. Note that, when the waterproof paper7is not provided, the coated regions50aand50bare formed to penetrate across: the surface3xof the back sheet3that faces the absorber4; the inside of the back sheet3; and the surface3yof the back sheet3that faces the peeling paper6.

Here, the coated regions50aand50bare formed by causing the adhesive5to penetrate into gaps among the material pieces (into interfiber spaces in a non-woven fabric, for example) of the back sheet3(the sheet pieces3A to3C).

(Method of Manufacturing Absorbent Article According to a Second Embodiment)

Hereinafter, with reference toFIGS. 6 to 8, a method of manufacturing the absorbent article1according to this embodiment will be briefly described.

As shown inFIG. 6, firstly, continua of sheet pieces3A to3C are placed on a continuum of peeling paper sheets6, while these continua are continuously conveyed on a line. Here, the continuum of peeling papers6is fed from a peeling paper roll60, while the continua of sheet pieces3A to3C are fed respectively from multiple back-sheet rolls30A to30C.

Here, the multiple back-sheet rolls30A to30C are deployed along the moving direction of the line and the multiple back-sheet rolls30A to30C are arranged so that the continuum of sheet pieces3A can partially overlap the continuum of sheet pieces3B, and so that the continuum of sheet pieces3B can partially overlap the continuum of sheet pieces3C.

Alternatively, as shown inFIG. 7, a single back-sheet roll having one or more cuts may be prepared, and arranged so that a continuum of sheet pieces fed from the back-sheet roll can partially overlap each other to form one or more of the continua of sheet pieces.

Still alternatively, as shown inFIG. 8, a single back-sheet roll may be prepared to feed a continuum of sheet pieces to be cut by a cutter70into multiple continua of sheet pieces, and arranged so that each of these multiple continua of sheet pieces can partially overlap each other to form one or more of the continua of sheet pieces.

Secondly, the adhesive5is applied in a predetermined pattern described above to each overlapping regions30xand30y(seeFIGS. 4 and 5) where adjacent two of the sheet pieces3A to3C overlap each other. Here, in the absorbent article1according to the first embodiment, the adhesive5is applied to be exposed only at the back side (the peeling paper6side) of the back sheet3. On the other hand, in the absorbent article1according to the present embodiment, the adhesive5is applied to be exposed at the top and back sides of the overlapping regions30xand30y. With the adhesive5, the sheet pieces3A to3C are joined together and the sheet pieces3A to3C are joined to the peeling paper6.

Thirdly, a continuum of waterproof paper sheets7is placed on the continuum of back sheets3, which is thus formed of the continua of sheet pieces3A to3C. The continuum of back sheets3are joined to the continuum of waterproof paper sheets7using the adhesive5exposed at the top side of the overlapping regions30xand30y.

Fourthly, an adhesive10bis applied onto the continuum of waterproof paper7, and then a continuum of absorber4is placed on the continuum of waterproof paper7and joined thereto.

Fifthly, an adhesive10ais applied onto the continuum of absorber4, and then a continuum of top sheets2is placed on the continuum of absorber4and joined thereto.

Sixthly, with a product cutter40, the resultant continuum is cut into shapes each corresponding to the absorbent article1.

In the absorbent article1according to the embodiment, the adhesive5is applied to the back sheet3. Nevertheless, the absorbent article1can be dispersed at a higher speed in a drainage pipe or in a septic tank while having an improved fastening capability to an undergarment.

In the absorbent article1, the back sheet3is formed of the multiple sheet pieces3A to3C. Accordingly, when the used absorbent article1is disposed of in a toilet, the adhesive5which joins the sheet pieces3A to3C together disintegrates in water, so that the back sheet3, a single sheet formed of multiple sheet pieces connected together, is separated back into the multiple sheet pieces3A to3C. Thus, the sheet pieces3A to3C can be made of a material hardly decomposable in water.

In the absorbent article1, the adhesive5which joins the sheet pieces3A to3C together is applied to be exposed at the top and back sides of the back sheet3. Accordingly, the adhesive5can also be used to fasten the absorbent article1to an undergarment.

In the absorbent article1, the adhesive5which joins the sheet pieces3A to3C together is applied in a pattern of shapes arranged at certain intervals. Accordingly, when the absorbent article1is put into water, water enters the inside thereof through the regions not coated with the adhesive5, which facilitates separation of the sheet pieces3A to3C from one another caused by the flow of water.

In particular, the constituent fibers are previously cut at the peripheries of the sheet pieces3A to3C, and the coated region50aand the non-coated region50b, which are coated with the adhesive5, are arranged at certain intervals. Accordingly, compared with a back sheet formed solely of a single sheet consisting of fibers entangled with one another, wherein the back sheet formed of a single sheet is broken as the fibers are untangled, the back sheet3can be broken at a higher speed than the back sheet formed of a single sheet.

In the absorbent article1, the fibers forming non-woven fabric (the back sheet3) are arranged to extend in the longitudinal direction of the absorbent article1. In addition, each overlapping regions30xand30ywhere adjacent two of the sheet pieces3A to3C overlap each other is also arranged to extend in the longitudinal direction of the absorbent article1. In other words, the back sheet3has no cut line extending in the width direction of the absorbent article1. Accordingly, liquid that flows in the extending direction of the fibers is less likely to leak out of the absorbent article1.

In the absorbent article1, the adhesive5is applied so as to penetrate through the multiple sheet pieces3A to3C in the thickness direction of the absorbent article1. Accordingly, the adhesive5can increase interlayer strength among the sheet pieces3A to3C by partially fixing the fibers in each of the sheet pieces3A to3C to the fibers in adjacent one of the sheet pieces3A to3C. In addition, this application of the adhesive5not only can prevent a phenomenon where part of the back sheet3and the adhesive5are left unpeeled from a wearer' s undergarment when the absorbent article1is peeled off from the undergarment, but also makes the sheet pieces3A to3C less likely to separate from one another.

Hereinafter, an absorbent article1according to Modification 1 of the present invention will be described with reference toFIG. 9. The following description of the absorbent article1according to Modification 1 is focused on differences from the absorbent article1according to the embodiment of the present invention.

As shown inFIG. 9, in the absorbent article1according to Modification 1, each overlapping region where adjacent two of the sheet pieces3A to3C overlap each other is provided in the back sheet3so as to extend in the width direction of the absorbent article1.

In the absorbent article1according to Modification 1, it is preferable to apply the adhesive5in a pattern designed to disperse a force applied to the absorbent article1when it is peeled off from a wearer's undergarment.

For example, such an application pattern of the adhesive5, specifically an application pattern formed by multiple coated regions coated with the adhesive5, should preferably be formed of rectangles arranged so that the shorter sides of the rectangles can extend perpendicular to the peeling directions of the absorbent article1.

Hereinafter, an absorbent article1according to Modification 2 of the present invention will be described with reference toFIG. 10. The following description of the absorbent article1according to Modification 2 is focused on differences from the absorbent article1according to the embodiment of the present invention.

As shown inFIG. 10, in the absorbent article1according to Modification2, the overlapping regions where adjacent two of the sheet pieces3A to3D overlap each other are provided in the back sheet3so as to extend both in the width and longitudinal directions of the absorbent article1. Further, each lengths of the sheet pieces3A to3D is shorter than the length of the back sheet3.

In the absorbent article1according to Modification 2, each of the sheet pieces3A to3D has the smallest size in length and width compared to the other embodiments shown in the figures and described herein. This provides the absorbent article1with improved dispersibility in water.

Hereinafter, an absorbent article1according to Modification 3 of the present invention will be described with reference toFIG. 11. The following description of the absorbent article1according to Modification 3 is focused on differences from the absorbent article1according to the embodiment of the present invention.

As shown inFIG. 11, in the absorbent article1according to Modification 3, each overlapping region where adjacent two of the sheet pieces3A to3C overlap each other is provided in the back sheet3so as to extend in a direction oblique to the longitudinal direction of the absorbent article1(at a 45° angle to the longitudinal direction, for example). Further, each lengths of the sheet pieces3A to3D is shorter than the length of the back sheet3.

While the present invention has been described in detail above by using the foregoing embodiment, it should be apparent to those skilled in the art that the present invention is not limited to the embodiment described herein. The present invention may be practiced in the form of modifications and variations without departing from the basic concept and scope of the invention as defined in the appended claims. It is to be therefore understood that the disclosure herein is for purposes of illustration only and is not intended to limit the scope of the present invention.

Note that the entire content of Japanese Patent Application No. 2008-165153 (filed on Jun. 24, 2008) is incorporated by reference into this application.

Industrial Applicability

As described above, the present invention provides an absorbent article that has an improved fastening capability to an undergarment, and that is dispersible at a higher speed in a drainage pipe or in a septic tank, and to provide a method of manufacturing such an absorbent article.