Absorbent article with resilient portion and method for manufacturing the same

Disclosed is an absorbent article including: a liquid-permeable topsheet on its skin surface; a backsheet on its garment surface; and an absorbent layer therebetween. First compressed portions and second compressed portions, in which the absorbent layer is compressed together with at least the topsheet, extend longitudinally of the absorbent article. The first compressed portions are disposed symmetrically about a longitudinal centerline of the absorbent article to define a central absorbent portion having the absorbent layer therebetween. The second compressed portions are disposed symmetrically about the longitudinal centerline and spaced outwardly apart from the first compressed portions. When the central absorbent portion is laterally compressed by an external force, resilient portions each defined between each adjacent pair of first and second compressed portions are permitted to exert a resilience against compression on the central absorbent portion.

This application is a continuation of PCT/JP03/011408 filed Sep. 8, 2003, which claims priority to Japanese Application Nos. 2002-263453 filed Sep. 9, 2002, and 2002-276393 filed Sep. 20, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an absorbent article suitable for absorbing menstrual blood and so on discharged from the female genital organ, more particularly, relates to an absorbent article having resilient portions for restoring the article to its original state even when it is deformed by compression or twisted during wear, and a method for manufacturing the same.

2. Related Art

Absorbent articles intended to absorb menstrual blood discharged from a female genital organ are typically constructed to include an absorbent layer, a liquid-permeable topsheet covering the skin surface of the absorbent layer, and a liquid-impermeable backsheet covering the garment surface of the absorbent layer. Generally, they are worn with the backsheet adhered to an inner side of a groin piece of an undergarment through a pressure-sensitive adhesive layer.

In order to certainly collect liquid discharged from an excretory part of a wearer by the absorbent article, the skin surface is preferably brought into close contact with the wearer's excretory part. If a clearance is caused between the skin surface of the absorbent article and the excretory part when the absorbent article is worn in the crotch, discharged liquid applied to the topsheet may flow along the topsheet to easily cause leakage laterally of the absorbent article or leakage toward the wearer's buttocks, which results in fouling the undergarment or other garments.

As disclosed in the following Patent Publications 1 to 3, therefore, there have been developed absorbent articles in which a portion between grooves formed in the skin surface is raised for close contact with the wearer's excretory part.

Patent Publication 1 discloses an absorbent article, in which a raised portion where an absorbent body is of an increased thickness is provided centrally while a pair of curved top-side grooves is formed on right and left sides of the raised portion. The top-side grooves can serve as a flexible hinge to facilitate folding of the absorbent body, which aims at deforming the raised portion to have an arc cross-section projecting toward the wearer.

Patent Publication 2 discloses an absorbent article, in which a skin contact surface has a longitudinally elongated projection surrounded by a recess. This aims at raising the projection for closely contacting the wearer's excretory part as well as at blocking liquid by the recess surrounding the projection for preventing diffusion to surroundings.

Patent Publication 3 discloses a substantially longitudinally elongated absorbent article, in which arc-shaped folding portions inwardly curved from longitudinal side edges are provided on a region where an absorbent body is present, so that leakage preventing wall forming regions are formed in the portions confined in the folding portions. The leakage preventing wall forming regions intended to rise toward the wearer's crotch at the time of wearing aim at preventing lateral leakage of discharged liquid.

FIG. 15is a sectional view schematically showing a state where such an absorbent article as disclosed in Patent Publications 1 to 3 is worn.

Referring toFIG. 15, the wearer's crotch and thighs are indicated by50and51, a groin piece of an undergarment to be applied to the crotch50is indicated by25, and the conventional absorbent article is indicated by60. This absorbent article60is adhered to and fixed on an inner side of the groin piece25. In the foregoing Patent Publications, a pair of grooves61,61is formed in the skin surface of the absorbent article60so that a central portion62between the grooves61,61can closely contact an excretory part in the crotch50.

When the absorbent article60is worn as attached to the groin piece25, as shown inFIG. 15, a lateral compressive force F is frequently applied to the groin piece25and the absorbent article60from the thighs51,51during walking. The compressive force makes the right and left grooves61,61approach each other, so that the lateral compressive force acts on the central portion62between the grooves61,61.

In the conventional absorbent article60, however, resiliency against the lateral compressive force mainly depends on resiliency of absorbent layer provided in the central portion62. Because the absorbent layer in the central portion62need feel soft to the crotch50and its liquid absorption capacity need be increased, its basis weight is high, whereas its density is low. Accordingly, when compressed and deformed, as shown inFIG. 15, its lateral resiliency is so poor that its width cannot be easily restored from the compressed and deformed state. When the absorbent article is twisted as a whole in accordance with the motion of the crotch, on the other hand, it cannot be easily restored from the twisted state.

Particularly when the absorbent layer is of a high basis weight and a low density, as set forth above, its resiliency decreases after absorption of discharged liquid such as menstrual blood, so that its bulkiness cannot be restored once the central portion62is crushed by pressure from the crotch50and its lateral resiliency against compression due to the compressive force F decreases drastically. Therefore, even after the thighs51,51are spread wide, the absorbent article remains compressed laterally or twisted, decreasing the area of the skin surface of the absorbent article60and easily forming a space between the article and the crotch50, which easily results in causing lateral leakage.

Furthermore, since the conventional ones disclosed in the foregoing Patent Publications are all constructed such that the grooves61are disposed one on each side, side portions63,63outside the grooves61easily contact the central portion62when deformed as shown inFIG. 15. As a result, discharged liquid applied to the central portion62tends to migrate to the side portions63,63and diffuse laterally of the absorbent article60. That is, the effect of diffusing discharged liquid through the grooves61,61cannot be achieved, which easily results in causing lateral leakage of discharged liquid.

In order to prevent lateral leakage of discharged liquid applied to the absorbent article, there have been developed leakage preventing walls extending longitudinally and opposed laterally on the skin surface of the absorbent article. The leakage preventing walls are constructed with elastic members for producing a longitudinal elastic shrinkage force disposed on a liquid-impermeable sheet, so that the sheets rise from the skin surface due to the elastic shrinkage force.

However, the conventional absorbent article is easily deformed or twisted during wear because its shape retention may be deteriorated when the absorbent article is subjected to the compressive force F or absorbs discharged liquid. In this case, front and rear rising points of the leakage preventing walls easily move toward the longitudinal centerline due to deformation of the article or move longitudinally due to twisting of the absorbent article. Accordingly, since the standing position of the leakage preventing walls is unstable, the leakage preventing walls may possibly twist or fall down toward the longitudinal centerline, decreasing the liquid absorption area of the skin surface.

In case where the leakage preventing walls are disposed in such a long absorbent article as disclosed in Patent Publications1and2, the leakage preventing walls become more unstable since the length of the leakage preventing walls need be increased. When a long absorbent article of this type is worn, the leakage preventing walls may move unexpectedly following the motion of the wearer's body, which results in causing twisting or falling down of the leakage preventing walls more easily.

SUMMARY OF THE INVENTION

The present invention has been worked out in view of the shortcomings in the prior art set forth above and has an object to provide an absorbent article, in which resiliency against lateral compression is improved to prevent leakage of discharged liquid, and a method for manufacturing the same.

Another object of the present invention is to provide an absorbent article, in which leakage preventing walls disposed on a skin surface thereof can be certainly kept in a standing position.

According to a first aspect of the present invention, there is provided an absorbent article comprising:

a liquid-permeable topsheet on a skin surface;

a backsheet on a garment surface; and

an absorbent layer between the topsheet and the backsheet, wherein

first compressed portions and second compressed portions, in which the absorbent layer is compressed together with at least the topsheet, extend longitudinally of the absorbent article, the first compressed portions being disposed symmetrically about a longitudinal centerline of the absorbent article to define a central absorbent portion having the absorbent layer therebetween, the second compressed portions being disposed symmetrically about the longitudinal centerline and spaced outwardly apart from the first compressed portions, whereinwhen the central absorbent portion is laterally compressed by an external force, resilient portions each defined between each adjacent pair of first and second compressed portions are permitted to exert a resilience against compression on the central absorbent portion.

In the absorbent article, since the resilient portions are provided between the first and second compressed portions, the absorbent article can be easily restored from a laterally compressed or twisted state to its original state due to resiliency of the resilient portions. Particularly when discharged liquid is absorbed by the central absorbent portion between the first compressed portions, the discharged liquid can be blocked by the first compressed portions to prevent the resilient portions from being wetted. Therefore, even after resiliency of the central absorbent portion is deteriorated by the absorption of discharged liquid, the resilient portions on both sides thereof can always produce sufficient resilience to restore the absorbent article from a laterally compressed or twisted state.

In the individual resilient portions, the absorbent layer may be compressed to have a higher density than in the central absorbent portion.

The resilient portions have a width that is preferably less than one half, more preferably less than one third, of a width of the central absorbent portion.

As the width of the resilient portions is decreased, the resilient portions between the first and second compressed portions may have a narrow higher-density layer, so that large resilience can be easily produced. As the resilient portions are narrowed, moreover, the resilient portions hardly feel uncomfortable against the wearer's skin.

In the individual resilient portions, the absorbent layer may be compressed due to formation of the first and second compressed portions.

In the individual resilient portions, alternatively, the absorbent layer of hydrophilic fibers may be compressed together with a nonwoven fabric of synthetic fibers due to formation of the first and second compressed portions.

In the latter case, preferably, the absorbent layer is compressed together with the nonwoven fabric also in the individual first compressed portions. For example, the nonwoven fabric may be a through-air bonded nonwoven fabric.

When not only the absorbent layer mainly comprised of hydrophilic fibers such as pulp but also the nonwoven fabric of synthetic fibers is disposed in the resilient portions, as set forth above, the resiliency can be improved more. Particularly because the resilient portions contain the synthetic fibers, the resiliency is hardly deteriorated even after the discharged liquid is applied to the resilient portions. When the first compressed portions contain the synthetic fibers, moreover, the synthetic fibers can be melted and solidified therein, so that the compressed state of the first compressed portions can be maintained even after wetted with the discharged liquid.

Between the topsheet and the backsheet, the individual resilient portions may have a resilient reinforcing member alone or in combination with the absorbent layer that is compressed due to formation of the first and second compressed portions.

The reinforcing member may be foamed urethane resin, foamed urethane resin treated to be hydrophilic, or synthetic rubber.

Preferably, the resilient portions approach each other the nearest at a lateral reference line of the absorbent article, and extend gradually away from the centerline as they extend away from the lateral reference line toward longitudinally opposed ends of the absorbent article. For example, the individual resilient portions may be in the shape of a line curved toward the centerline.

Preferably, the individual resilient portions have a portion of constant width, over which the first and second compressed portions are spaced a constant distance apart from each other.

With this construction, a force from the wearer's thighs can be almost uniformly exerted on every part of the resilient portions. In addition, the resilient portions hardly feel uncomfortable against the thighs.

The absorbent article may be constructed such that side portions are each defined between each second compressed portion and a corresponding longitudinally extending side edge of the absorbent article, and an elastic shrinkage force is longitudinally exerted on the side portions.

In this case, the side portions can rise toward the wearer's skin due to the elastic shrinkage force when applied to the wearer's crotch, thereby serving as leakage preventing walls for preventing lateral leakage. Here, since the first compressed portions, the second compressed portions and the resilient portions are disposed between the central absorbent portion and the side portions, the central absorbent portion hardly contact the side portions, so that migration of discharged liquid from the central absorbent portion to the side portions can be prevented to improve the leakage preventing effect of the side portions.

In one embodiment of the absorbent article, longitudinally extending sheets are disposed on the skin surface with the central absorbent portion externally exposed therebetween, the individual sheets being fixed on the skin surface at front and rear portions thereof while being raised from the skin surface at an intermediate portion thereof to form a leakage preventing wall, wherein at least one of front and rear rising points of the leakage preventing wall is in proximity to the second compressed portion.

The rising points may be in proximity to ends of the second compressed portion.

With the rising points of the leakage preventing wall thus provided in proximity to the second compressed portion or ends of the second compressed portion, i.e., the resilient portion, irregular motion of the rising points of the leakage preventing wall can be inhibited, thereby preventing twisting or falling down of the leakage preventing wall even when a pressure is applied from the thighs in a wet state where discharged liquid is absorbed.

In another embodiment of the absorbent article, first rear compressed portions are disposed to gradually approach each other as they extend continuously from the first compressed portions toward a rear edge of the absorbent article, and second rear compressed portions are each disposed between each first rear compressed portion and corresponding one of the side edges and spaced apart from the first rear compressed portions, wherein

longitudinally extending sheets are disposed on the skin surface with the central absorbent portion externally exposed therebetween, the individual sheets being fixed on the skin surface at front and rear portions thereof while being raised from the skin surface at an intermediate portion thereof to form a leakage preventing wall, wherein a front rising point of the leakage preventing wall is in proximity to the first compressed portion while a rear rising point of the leakage preventing wall is in proximity to the second rear compressed portion.

The rear rising point of the leakage preventing wall may be in proximity to a front end of the second rear compressed portion.

Also in this case, since the rear rising point of the leakage preventing wall is subjected to resilience due to a rear resilient portion defined between the first rear compressed portion and the second rear compressed portion, irregular motion can be inhibited, thereby preventing twisting or falling down of the leakage preventing wall.

Here, the proximity preferably means that a distance is 45 mm or less, more preferably 25 mm or less.

The absorbent article of the present invention is suitable for use as a sanitary napkin.

Since sanitary napkins are worn in the crotch even during the daytime activity, they are easily contracted or twisted by a compressive force from the wearer's thighs. However, because the absorbent article of the present invention has the resilient portions, it can be easily restored from such contracted or twisted state.

According to a second aspect of the present invention, there is provided a method for manufacturing an absorbent article comprising: a liquid-permeable topsheet on a skin surface; a backsheet on a garment surface; and an absorbent layer between the topsheet and the backsheet, first compressed portions and second compressed portions, in which the absorbent layer is compressed together with at least the topsheet, extending longitudinally of the absorbent article, the first compressed portions being disposed symmetrically about a longitudinal centerline of the absorbent article, the second compressed portions being disposed symmetrically about the longitudinal centerline and spaced outwardly apart from the first compressed portions, the method comprising

the step of pressing at least the absorbent layer from the skin surface with a pressure member having first projections spaced apart from each other for forming the first compressed portions and second projections disposed outside the first projections for forming the second compressed portions, wherein

the pressure member has: recesses each formed between each adjacent pair of first and second projections to have a first depth from a top of the first projection; a first base formed between the first projections to have a second depth; and a second base formed outside the first projections to have a third depth, wherein the first depth is smaller than the second depth and smaller than the third depth so that the absorbent layer is more highly compressed at locations between the first and second compressed portions with the recesses than at locations confronted by the first and second bases.

In this method, it is preferred that the absorbent article is not substantially pressed with the first and second bases.

However, it is possible to lightly press the absorbent layer with the first and second bases as long as the absorbent layer has a lower density at the locations confronted by the first and second bases than at the locations pressed with the recesses.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the present invention, the absorbent article refers to devices which are intended to be worn in the crotch of a wearer to absorb various exudates discharged from the wearer's body, such as menstrual blood, urine, and vaginal discharge, but in the following embodiments, the absorbent article is shown embodied in a sanitary napkin whose primary object is to absorb menstrual blood discharged from the vaginal opening of a woman. It should be noted that the absorbent article has two major surfaces: of which one surface intended to be worn toward the wearer's crotch is referred to as “skin surface”, while the other surface is referred to as “garment surface” regardless of whether a garment is worn outside the absorbent article or not.

As used herein, the term “compressed portions” refers to portions where an absorbent layer is highly compressed together with at least a topsheet and they remain in such a highly compressed state.

As used herein, the term “resilient portions” refers to portions which can produce a larger resilience (repulsive force) than a central absorbent portion located therebetween when the absorbent article is laterally compressed.

As used herein, the term “longitudinal centerline” refers to a line which extends longitudinally to divide the absorbent article laterally in two. On the other hand, the term “lateral reference line” does not necessarily refer to a line which extends laterally to divide the absorbent article longitudinally in two. In the following embodiments where right and left first compressed portions are not parallel with each other, a line which extends laterally at a location where the right and left first compressed portions approach each other the nearest, is taken as the lateral reference line. If the location where the right and left first compressed portions approach each other the nearest cannot be specified, such as when they are parallel with each other, a line which extends laterally to cross a longitudinal center of a portion intended to be brought into contact with the vaginal opening during wear, is taken as the lateral reference line.

FIG. 1is a top plan view showing a sanitary napkin1as an absorbent article according to a first embodiment of the present invention, wherein the skin surface faces upward;FIG. 2Ais a half sectional view of the sanitary napkin taken along line IIa-IIa ofFIG. 1, andFIG. 2Bis a half sectional view of the sanitary napkin taken along line IIb-IIb ofFIG. 1;FIG. 3is a sectional view showing a state where the sanitary napkin is attached to a groin piece of an undergarment;FIG. 4is a sectional view schematically showing a state where the groin piece and the sanitary napkin are deformed due to a lateral compressive force; andFIG. 5is a top plan view schematically showing the deformed state.

As shown in the top plan view ofFIG. 1, the sanitary napkin1is of an elongated shape, wherein longitudinally extending right and left side edges1aand1bare laterally spaced a constant distance apart from a longitudinal centerline Oy-Oy, while front and rear end edges1cand1din the shape of an outwardly curved line are longitudinally spaced apart from a lateral reference line Ox-Ox. It should be noted that in the case where the sanitary napkin is provided with wings18and18, as shown inFIG. 1, the right and left side edges1aand1bwill be described as inclusive of imaginary cut lines A and A extending along bases of the wings18and18.

As shown in the sectional views ofFIGS. 2 and 3, the sanitary napkin1has a liquid-impermeable backsheet2appearing on the garment surface and a liquid-permeable topsheet3appearing on the skin surface. Between the backsheet2and the topsheet3, disposed is an absorbent layer4. The absorbent layer4is constructed to include: a first absorbent layer4awhose periphery is shown by a dotted line inFIG. 1; a second absorbent layer4bhaving a smaller area than the first absorbent layer4aand laid on the first absorbent layer4a, whose periphery is also shown by a dotted line inFIG. 1; and a third absorbent layer4chaving a smaller area than the second absorbent layer4band laid on the second absorbent layer4bwithin a central absorbent portion5of an hourglass shape.

Here, at least the topsheet3and the absorbent layer4are compressed to form compressed portions10. The compressed portions10are formed by embossing with a pressure member that will be described later, wherein the first absorbent layer4a, the second absorbent layer4b, the third absorbent layer4cand the topsheet3are stacked one upon another and then heated under pressure applied from the side of the topsheet3. As a result, the compressed portions10have high-density compressed portions10a, in which the absorbent layer and the topsheet3are pressed until they get almost filmy, and medium-density compressed portions10b, in which although doesn't get filmy, the absorbent layer is of a higher density than in portions other than the compressed portion10, between adjacent high-density compressed portions10a. With the high-density compressed portions10aand the medium-density compressed portions10balternating with each other, each compressed portion10forms a compressed groove where the skin surface of the sanitary napkin1is recessed toward the backsheet2.

The compressed portions10comprise first compressed portions11,11that are disposed symmetrically about the longitudinal centerline Oy-Oy and second compressed portions12,12that are disposed symmetrically about the longitudinal centerline Oy-Oy and spaced outwardly apart from the first compressed portions11,11. The first compressed portions11,11and the second compressed portions12,12are compressed grooves extending along arcuate lines that are curved toward the longitudinal centerline Oy-Oy, wherein the second compressed portions12,12are spaced a constant distance apart from the first compressed portion11,11, all along the second compressed portions12,12.

The compressed portions10also comprise lateral compressed portions13,13that are connected between the first compressed portions11,11at their front ends and rear ends. The lateral compressed portions13,13are compressed grooves extending along arcuate lines that are curved away from the lateral reference line Ox-Ox. In this embodiment, the region surrounded by the first compressed portions11,11and the lateral compressed portions13,13is the central absorbent portion5, and the second compressed portion12,12are located outside the central absorbent portion.

The compressed portions10further comprise forwardly extending compressed portions14,14that are extended continuously from the first compressed portions11,11to project forwardly beyond the lateral compressed portion13and rearwardly extending compressed portions15,15that are also extended continuously from the first compressed portions11,11to project rearwardly beyond the lateral compressed portion.

The regions between the first compressed portions11,11and the second compressed portions12,12are resilient portions6,6. The resilient portions6,6are arcuate regions with a constant width all along the second compressed portions12,12. On the other hand, the region between the right side edge1aand the right second compressed portion12and the region between the left side edge1band the left second compressed portion12are side portions7,7.

The absorbent layer4is provided to extend over the central absorbent portion5and the resilient portions6,6and further extend outwardly across the second compressed portions12,12halfway through the side portions7,7.

In the central absorbent portion5, the first absorbent layer4a, the second absorbent layer4band the third absorbent layer4care stacked one upon another to provide a high-basis weight, bulky central absorbent layer4A, as shown inFIG. 2A. On the other hand, resilient layers4B provided in the resilient portions6are absorbent layers of a relatively high basis weight, in which the first absorbent layer4aand the second absorbent layer4bare stacked. In the resilient layer4B, furthermore, the absorbent layer is compressed to have an increased density. In the side portions7, then, provided are side absorbent layers4C consisting of the first absorbent layer4a.

The basis weight of the resilient layers4B may be equal to or slightly less than that of the central absorbent layer4A. However, it is preferred that the basis weight of the resilient layers4B is greater than that of the side absorbent layers4C so that the resilient portions6,6can produce sufficient resilience.

Upon formation of the individual resilient portions6, the topsheet3and the absorbent layer are pressed with embossing projections. At this time, while the topsheet3and the absorbent layer are heated under pressure to form the compressed grooves, the topsheet3subjected to the pressure from the projections is stretched laterally between the first and second compressed portions11and12that are laterally spaced only a short distance apart from each other. Between the first and second compressed portions11and12, accordingly, the absorbent layer is held down due to resilience produced by the stretched topsheet3. With the compressed portions11and12being thus formed, the resilient layer4B in the resilient portion6can be made denser than the central absorbent layer4A and the side absorbent layer4C.

In an alternative, the high-density resilient layer4B may be formed such that an absorbent layer that has been compressed in advance to have an increased density is fed at locations corresponding to the resilient portions6prior to the formation of the first and second compressed portions11and12, and then the absorbent layer is compressed more with the formation of the compressed portions11and12.

As shown inFIGS. 2A and 3, since the first compressed portions11,11and the second compressed portions12,12are compressed grooves that are recessed toward the backsheet2, the central absorbent portion5and the resilient portions6,6rise toward the wearer's skin. As will be described later, in the case where the resilient portions6,6rise toward the wearer's skin, the central absorbent portion5can be easily separated from the side portions7,7in a deformed state ofFIG. 4.

Among the compressed portions10, at least the first and second compressed portions11and12have a higher density (in both the high-density compressed portions10aand the medium-density compressed portions10b) than the central absorbent layer4A, the side absorbent layer4C and the resilient layer4B. Accordingly, the first and second compressed portions11and12can serve as flexible hinges along which the sanitary napkin can be easily bent. The lateral compressed portions13,13, the forwardly extending compressed portions14,14and the rearwardly extending compressed portions15,15may also serve as flexible hinges.

As shown inFIGS. 1 and 2A, liquid-impermeable sheets20,20are provided on the skin surface at two sides thereof, and the right and left liquid-impermeable sheets20,20form right and left leakage preventing walls21,21, respectively. Because the right and left liquid-impermeable sheets20,20are of symmetrical configuration and the right and left leakage preventing walls21,21are of symmetrical construction about the longitudinal centerline Oy-Oy, only the right liquid-impermeable sheet20and the right leakage preventing wall21will be described hereinbelow, and the description of the left ones will be omitted, as well as the reference numerals for describing the construction of the left leakage preventing wall will be omitted from the drawings.

As shown inFIGS. 2A and 2B, the liquid-impermeable sheet20is folded in two with longitudinally extending elastic members22, such as rubbers, held therebetween in a stretched state, wherein the confronting surfaces of the folded sheet are bonded together along with the elastic members22. The liquid-impermeable sheet20thus folded in two has a first panel21aand a second panel21cresulting from further folding on a longitudinally extending fold line21b.

The first panel21ais bonded to the skin surface of the sanitary napkin1in a region hatched with dotted lines inFIG. 1. InFIG. 1, the boundary line between the bonded region and the unbonded region in the first panel21aincludes an intermediate boundary line22a, a front boundary line22band a rear boundary line22c. In the region surrounded by the boundary lines22a,22band22c(i.e., the region not hatched with dotted lines), the first panel21ais not bonded to the skin surface.

On the other hand, the second panel21cis laid on and bonded to the first panel21ain a region between a front end24aof the front boundary line22band the front end edge1c, as shown inFIG. 2B. The second panel21cis also laid on and bonded to the first panel21ain a region between a rear end24bof the rear boundary line22cand the rear end edge1d. It should be noted that the second panel21cis not bonded to the first panel21ain the remaining region between the front end24aand the rear end24b.

The elastic members22are provided to extend at least over the region between the front end24aand the rear end24b, so that in a free state where no external force is exerted on the sanitary napkin1, an elastic shrinkage force acts on the second panel21cof the liquid-impermeable sheet20in such a manner as to make the front end24aand the rear end24bapproach each other. Between the front end24aand the rear end24b, accordingly, the first panel21aand the second panel21crise from the intermediate boundary line22ato thereby form the leakage preventing wall21of a length L1.

Here, the front end24aof the front boundary line22bis referred to as front rising point of the leakage preventing wall21, while the rear end24bof the rear boundary line22cis referred to as rear rising point of the leakage preventing wall21.

In the sanitary napkin1, the front rising point24aof the leakage preventing wall21is in proximity to a front end12aof the second compressed portion12, i.e., in proximity to a front end of the resilient portion6. The least straight-line distance between the front rising point24aand the front end12aof the second compressed portion12is 45 mm or less, preferably 40 mm or less.

Likewise, the rear rising point24bof the leakage preventing wall21is in proximity to a rear end12bof the second compressed portion12, i.e., in proximity to a rear end of the resilient portion6. The least straight-line distance between the rear rising point24band the rear end12bof the second compressed portion12is 45 mm or less, preferably 30 mm or less.

Here, the straight-line distance between the rear rising point24band the rear end12bis preferably smaller than the straight-line distance between the front rising point24aand the front end12a. This is because when the sanitary napkin1is worn, the rear rising point24bclose to the wearer's buttocks tends to move more freely. The motion of the rear rising point24bcan be easily inhibited with the rear rising point24bthus located in proximity to the resilient portion6.

As shown inFIG. 1, the sanitary napkin1has the wings18,18projecting outwardly from the right side edge1aand the left side edge1b. The wings18,18are constructed with the backsheet2and the liquid-impermeable sheets20bonded together.

On an exterior surface of the backsheet2, there are provided a pressure-sensitive adhesive layer (not shown) for bonding a central portion of the sanitary napkin1to a groin piece of an undergarment and a pressure-sensitive adhesive layer (not shown) for bonding the wings18,18to an outer side of the groin piece of the undergarment.

FIG. 3shows a state where the sanitary napkin1is attached to a groin piece25of an undergarment.

The sanitary napkin1is centrally bonded to an inner side of the groin piece25through the pressure-sensitive adhesive disposed on the exterior surface of the backsheet2. On the other hand, the wings18,18are folded back against the outer side of the groin piece25so as to be wrapped around two side edges of the groin piece25, whereby the wings18,18are bonded to the outer side of the groin piece25through the pressure-sensitive adhesive.

When the undergarment is worn to bring the sanitary napkin1into contact with the wearer's crotch, the sanitary napkin1tends to deform along the surface of the wearer's crotch. At this time, since the first compressed portions11,11and the second compressed portions12,12can serve as the flexible hinges, the sanitary napkin1can be easily deformed to have its skin surface recessed, as shown in the section ofFIG. 4. In addition, since the sanitary napkin is recessed also in the longitudinally direction to have the front end edge1cand the rear end edge1dapproach each other, the leakage preventing walls21,21subjected to the longitudinal shrinkage force of the elastic members22rise from the skin surface to come into contact with the wearer's crotch, as shown inFIG. 4.

Here, since the longitudinal shrinkage force of the elastic members22also acts on the side portions7,7, the side portions7,7tend to bend inwardly upwardly inFIG. 3with the second compressed portions12,12serving as the flexible hinges. Therefore, the side portions7,7rise slightly slantwise with the right side edge1aand the left side edge1bfacing toward the wearer's body, as shown inFIG. 4, so that lateral leakage of menstrual blood can be easily prevented by the slanted side portions7,7and the leakage preventing walls21,21rising from the side portions7,7.

As shown inFIG. 4, moreover, since the side portions7,7rise toward the wearer's crotch50from the second compressed portions12,12, the leakage preventing walls21,21are supported from below by the side portions7,7containing the side absorbent layers4C,4C, so that the leakage preventing walls21,21can be certainly kept in close contact with the wearer's crotch. At this time, since the side portions7,7are located beneath the leakage preventing walls21,21and halfway through the thickness of the deformed sanitary napkin1and the protruding resilient portions6,6are located inside the side portions7,7, the leakage preventing walls21,21may possibly contact the side portions7,7but hardly contact the resilient portions6,6. Accordingly, even if menstrual blood flowing along the wearer's crotch is adhered to the leakage preventing walls21,21, the menstrual blood can be prevented from contacting the resilient portions6,6. As a result, since the resilient portions6,6are hardly wetted, their resiliency can be prevented from deteriorating.

Furthermore, front and rear portions of the sanitary napkin1can be bent with the lateral compressed portions13,13serving as the flexible hinges, so that the front portion forward from the lateral compressed portion13contacts the mons pubis while the rear potion rearward from the lateral compressed portion13contacts the buttocks. Still furthermore, the front portion can deform to conform to the mons pubis with the forwardly extending compressed portions14,14serving as the flexible hinges, while the rear portion can deform to conform to the buttocks with the rearwardly extending compressed portions15,15serving as the flexible hinges. In the front portion forward from the lateral compressed portion13and the rear potion rearward from the lateral compressed portion13, moreover, since there are present the forwardly extending compressed portions14,14and the rearwardly extending compressed portions15,15, which are arranged in longitudinal pairs, the front and rear portions can be made stiff enough to withstand twisting or distortion, so that the sanitary napkin1can easily be kept flat in the front and rear portions.

When the distance between thighs51,51is narrowed during wear of the sanitary napkin1, a lateral compressive force F acts on the groin piece25and the sanitary napkin1from the thighs51,51. The compressive force F functions to shorten the width of the sanitary napkin1and also acts on the resilient portions6,6as a force toward the longitudinal centerline Oy-Oy.

Here, since the sanitary napkin1is of a constant width, the compressive force F acts particularly strongly along the lateral reference line Ox-Ox to shorten the width. However, the resilient portions6,6between the first and second compressed portions11and12are in the shape of a curved line, and as shown inFIG. 5, the resilient portions6,6are located along the curved surfaces of the inner sides of the thighs51,51to be spaced an almost constant distance apart from the inner sides of the thighs51,51, all along the resilient portions6,6. Therefore, the compressive force F uniformly acts on the entire length of the resilient portions6,6without producing a great difference in force.

Thus, since the compressive force F is uniformly exerted on every part of the stiff resilient portions6,6, the compressive force is not concentrated at the lateral reference line Ox-Ox but distributed longitudinally to act on the central absorbent portion5between the resilient portions6,6. Therefore, the width of the central absorbent portion5can be uniformly shortened without causing extreme partial narrowing.

As the high-density, stiff resilient portions6,6approach each other, moreover, the central absorbent portion5provided therebetween is pushed up toward the wearer's body and pressed against the crotch50. Thus, the central absorbent portion5comes into close contact with the vaginal opening. In this state, the resilient portions6,6function to support the central absorbent portion5from below, thereby keeping the central absorbent portion5in close contact with the vaginal opening.

The resilient layers4B,4B of the resilient portions6,6, in which the absorbent layer is compressed to have an increased density, are highly laterally resilient. Therefore, when the thighs51,51are spread wide, the central absorbent portion5can be easily laterally restored due to the resiliency of the resilient portions6,6. Moreover, even if the sanitary napkin1is twisted during wear, the twisted sanitary napkin can be easily restored due to the resiliency of the resilient portions6,6. Particularly because the resilient portions6,6are of a constant width and curved along the thighs51,51, the compressive force F acting on the resilient portions6,6can be relieved substantially simultaneously and uniformly for every part of the resilient portions6,6when the thighs51,51are spread wide, so that the width can be uniformly restored for every part of the central absorbent portion5.

It should be noted that the first compressed portions11, the second compressed portions12and the resilient portions6are preferably curved as shown in Figures, so as to minimize the variation in distance between respective parts of the individual resilient portions6,6and the thighs51,51so that the compressive force F can be applied to the resilient portions6,6as uniformly as possible and the compression can be relieved as uniformly as possible when the compressive force F is released. However, a similar effect can be obtained as long as the first compressed portions11, the second compressed portions12and the resilient portions6approach each other the nearest at the lateral centerline Ox-Ox and extend away from the longitudinal centerline Oy-Oy as they extend longitudinally away from the lateral centerline Ox-Ox. The compressed portions11,12and the resilient portions6,6may extend in the shape of an arc of a circle or ellipse, a trapezoid or a “V”, for example. The first compressed portions11and the second compressed portions12may extend in the shape of a zigzag line or wavy line, as long as they approach each other the nearest at the lateral centerline Ox-Ox and extend away from the longitudinal centerline Oy-Oy as they extend longitudinally away from the lateral centerline Ox-Ox.

Menstrual blood discharged from the vaginal opening is mainly applied to the central absorbent portion5that is in close contact with the vaginal opening and is passed through the topsheet3and then absorbed by the central absorbent layer4A. Since the central absorbent portion5is surrounded by the first compressed portions11,11and the lateral compressed portions13,13, outward diffusion of menstrual blood can be easily prevented by these compressed portions, so that the menstrual blood can be diffused in and absorbed by the central absorbent portion5, thereby fully exploiting the liquid absorption capacity of the central absorbent layer4A.

When the central absorbent layer4A of a high basis weight and a low density absorbs menstrual blood, its resiliency against compression will be deteriorated. On the other hand, since the resilient layers4B,4B in the resilient portions6,6are highly compressed, their resiliency can be maintained even if the menstrual blood infiltrates them. Accordingly, even in a wet state where the menstrual blood is given thereto, the width of the central absorbent portion5can be restored every time the thighs51,51are spread wide. In addition, since the central absorbent portion5is pressed against the vaginal opening by the resilient portions6,6, it is hardly spaced apart from the vaginal opening even if the menstrual blood given to the central absorbent layer4A deteriorates compression recovery properties.

Furthermore, when the sanitary napkin1is laterally compressed, as shown inFIG. 4, the resilient portions6,6are located at both sides of the central absorbent portion5and the side portions7,7are located outside of them. Therefore, the surfaces of the side portions7,7hardly directly contact the surface of the central absorbent portion5. Accordingly, the menstrual blood absorbed in the central absorbent portion5hardly migrates to the side portions7,7, thereby preventing undesirable diffusion of menstrual blood. In addition, even when the menstrual blood flows laterally along the surface of the central absorbent portion5, it can be received and blocked by the resilient portions6,6, thereby preventing the flow toward the side portions7,7.

With the resilient portions6,6thus provided at right and left sides, the deformed sanitary napkin1can be restored to its original state immediately, especially at portions adjacent to the resilient portions6,6.

The deformed sanitary napkin1can be likewise restored even after absorption of the menstrual blood. As has been described hereinbefore, the front rising point24aand the rear rising point24bof the leakage preventing wall21are both in proximity to the resilient portion6with the straight-line distance being set at 45 mm or less. Therefore, even when the sanitary napkin1is deformed during wear to have the rising points24a,24bapproach the longitudinal centerline Oy-Oy, they can be easily restored to their original positions after the external force is relieved. Accordingly, the leakage preventing walls21can be prevented from undesirably twisting, and in addition, since the positions of the rising points24a,24bare stabilized, the leakage preventing walls21,21can be prevented from falling down to cover the surface of the central absorbent portion5. As a result, the effect of preventing lateral leakage of menstrual blood can be improved by the leakage preventing walls21,21.

Here, since the first compressed portions11, the second compressed portions12and the resilient portions6are curved toward the longitudinal centerline Oy-Oy, the front and rear ends12aand12bof the second compressed portion12easily approach the rising points24aand24b, so that the positions of the rising points24aand24bcan be easily stabilized with the resilient portions6.

In the embodiment shown inFIG. 1, the front rising point24ais located forward of the front end12aof the second compressed portion12, but it should be noted that the rising point24amay be located between the second compressed portion12and the right side edge1aor the rear rising point24bmay be located between the second compressed portion12and the right side edge1a. Here, the least straight-line distance between the rising point24aor24band the second compressed portion12is preferably 45 mm or less, more preferably 25 mm or less.

Hereinbelow, preferred values for the individual components will be described. Also in other embodiments that will be described later, it is preferred that the portions having the same construction as those in the first embodiment are of similar values. Hereinbelow, although the absorbent layer is constructed by wrapping fibers such as pulp in a hydrophilic paper or the like, the density and basis weight of the absorbent layer are measured without the hydrophilic paper or the like.

Preferably, the central absorbent layer4A is of a large liquid absorption capacity so as to be able to absorb menstrual blood sufficiently in the central absorbent portion5. Also preferably, it is soft to the touch and so resilient as to be able to restore its thickness when a pressure exerted thereon from the wearer's body is relieved.

The central absorbent layer4A preferably has a density in the range of 0.05 to 0.15 g/cm3. The central absorbent layer4A preferably has a basis weight from 500 to 1200 g/m2, more preferably, from 500 to 1000 g/m2. If they are set within the above-mentioned ranges, sufficient liquid absorption capacity and sufficient resiliency against vertical compression can be realized.

The central absorbent portion5has a width W1at the lateral reference line Ox-Ox, which is preferably in the range of 15 to 50 mm, more preferably in the range of 20 to 40 mm. The first reason is that the crotch width of average women is about 30 mm. The second reason is that even if the side portions7,7and the leakage preventing walls21,21fall down toward the longitudinal centerline Oy-Oy, a certain area of the surface of the central absorbent portion5can be kept exposed for receiving menstrual blood as long as the width W1is set within the above-mentioned range.

The resilient layers4B provided in the resilient potions6have a higher density than the central absorbent layer4A and the side absorbent layers4C, but the thickness of the resilient portions6is not very small.

More specifically, the resilient portions6are formed such that an absorbent layer having a basis weight from 300 to 800 g/m2, preferably from 350 to 600 g/m2, is compressed and squeezed at locations between the first and second compressed portions11,12having a width W4from 1.5 to 3.5 mm, to thereby increase the density of the absorbent layer to 0.1 to 0.25 g/cm3.

Furthermore, the resilient portions6are shaped to protrude with a width W2of 3 to 10 mm and a thickness of 2 to 6 mm from the exterior surface of the backsheet2to the exteriors surface of the topsheet3.

With this construction, the resilient portions6,6provided between the central absorbent portion5and the side portions7,7can be made firm and highly resilient. In addition, their bulkiness and resiliency can be prevented from decreasing even when wet.

In the central absorbent portion5and the resilient portions6,6, an additional layer such as nonwoven fabric of synthetic fibers may be provided, together with the absorbent layer of hydrophilic fibers, between the topsheet3and the backsheet2, as will be described later. In this case, the preferred density range refers to the density of the absorbent layer exclusive of the nonwoven fabric, while the preferred basis weight refers to that of the absorbent layer inclusive of the nonwoven fabric.

The length (dimension measured in parallel with the longitudinal centerline Oy-Oy) of the resilient portions6,6depends on the length of the second compressed portions12,12. If the length of the resilient portions6,6is too short, the width of the central absorbent portion5cannot be restored sufficiently; if it is too long, the stiffness of the whole sanitary napkin is excessively increased so that it feels uncomfortable against the wearer's crotch. The length of the resilient portions6,6is preferably from 40 mm to 100 mm. However, in case of long-type sanitary napkins for night-time use or heavy menstrual bleeding such as shown inFIG. 10, the length of the resilient portions6,6may be in excess of 100 mm. For example, when the sanitary napkin is the long type having a length of about 380 mm, the upper limit of the length of the resilient portions6,6is about 120 mm. If the length is in excess of 100 mm (in excess of 120 mm in case of the long type), the sanitary napkin1may possibly feel stiff against the wearer's body.

The side absorbent layers4C have a density in the range of 0.05 to 0.15 g/cm3, which is lower than that of the resilient layers4B but preferably almost similar to that of the central absorbent layer4A. On the other hand, the side absorbent layers4C have a basis weight which is lower than that of the resilient layers4B, and for example, preferably about 300 to 450 g/m2. The side absorbent layers4C have a width W3, which is preferably in the range of 10 to 35 mm, more preferably in the range of 10 to 20 mm.

The upper limit of the basis weight should not be limited to the above-mentioned range, but may be 600 g/m2in case of sanitary napkins.

In the first and second compressed portions11,12of the compressed portions10, it is preferred that the density of the most densified portions, i.e., the high-density compressed portions10ais sufficiently higher than those of the central absorbent layer4A, the resilient layers4B and the side absorbent layers4C. In order that the resilient portions6,6can independently produce sufficient resilience, the density of the high-density compressed portions10aneed be at least 0.3 g/cm3and is preferably in the range of 0.5 to 1.5 g/cm3. Here, the density of the medium-density compressed portions10bin the compressed portions10need not be set in the above-mentioned range so as to provide the resilient portions6,6with sufficient resiliency. However, it is also preferred to set the density of the medium-density compressed portions10bin the above-mentioned range so as to keep the density of the resilient portions6,6high and facilitate folding on the first compressed portions11,11and the second compressed portions12,12.

Next, preferred materials for the individual components will be described.

For the topsheet3, a synthetic resin film formed with a large number of liquid passage holes, a synthetic resin film formed in the shape of a net or a through-air bonded nonwoven fabric of chemical fibers may be used. In an alternative, a composite material, in which the synthetic resin film having the liquid passage holes appears on the skin surface and the through-air bonded nonwoven fabric is laid beneath it, may be used. In this case, the synthetic resin film is formed of polyethylene resin containing titanium oxide as a whitening agent, while the through-air bonded nonwoven fabric is formed of sheath/core bicomponent synthetic fibers of which the core component is polyethylene terephthalate (PET) containing titanium oxide and the sheath component is polyethylene (PE), the sheath/core bicomponent synthetic fibers being thermally fusion-bonded together by means of hot air.

It is also possible to use different nonwoven fabrics such as spunlaced nonwoven fabric, spunbonded nonwoven fabric and the like for the topsheet3.

The backsheet2is a liquid-impermeable, breathable sheet such as a polyethylene (PE) or polypropylene (PP) film formed with minute pores. The minute pores may be appropriately distributed over the film for improving breathability such as by adding inorganic filler such as CaCO3and BaSO4to the plastic film, followed by drawing. The film may have a thickness of about 15 to 50 μm. In an alternative, a material in which a thermoplastic resin is laminated to a nonwoven fabric may be used.

The first absorbent layer4a, the second absorbent layer4band the third absorbent layer4care formed by accumulating fluff pulp such as ground pulp, mercerized pulp or crosslinked pulp. After stacked one upon another, the absorbent layers4a,4band4care entirely wrapped in a hydrophilic paper. The pulp may be mixed with synthetic absorbent polymer such as polyacrylate, polyacrylamide and maleic anhydride or natural absorbent polymer such as starch and cellulose. In an alternative, absorbent polymer in the form of sheet may be contained therein.

Particularly in the case where the absorbent polymer, which may be in the form of sheet, is contained in the resilient portions6,6, the bonding strength between pulp can be increased when they are wetted by absorption of menstrual blood, thereby increasing the stiffness of the resilient portions6,6.

For the liquid-impermeable sheets20for forming the leakage preventing walls21, a spunbonded nonwoven fabric, a meltblown nonwoven fabric or a laminate thereof may be used. Preferably, the sheets20are treated to be water-repellent.

In appropriate portions but for the compressed portions10, the backsheet2, the topsheet3, the absorbent layer4and the liquid-impermeable sheets20are bonded to each other through an adhesive.

In the followings, other embodiments of the present invention will be described. Hereinafter, the detailed description of the portions having the same construction as those of the first embodiment will be omitted by designating them by the common reference numerals.

FIG. 6is a half sectional view showing a sanitary napkin1A according to a second embodiment of the present invention.

In this embodiment, a nonwoven fabric8of synthetic fibers is laid on the absorbent layers4A and4B to extend from the central absorbent portion5, beyond the first compressed portions11,11, to the resilient portions. This nonwoven fabric may be a through-air bonded nonwoven fabric, for example.

The through-air bonded nonwoven fabric may be formed such that eccentric sheath/core bicomponent synthetic fibers (e.g., having fineness of 4.4 dtex and length of 50 mm) of which the core component is polypropylene (PP) and the sheath component is polyethylene (PE) are heat treated for one minute with hot air of 135 degrees centigrade, wherein the fibers are coated with a hydrophilic lubricant. The through-air bonded nonwoven fabric has a density which is lower than those of the central absorbent layer4A and the topsheet3and is in the range of 0.005 to 0.3 g/cm3. The through-air bonded nonwoven fabric has a thickness of 0.5 to 2 mm and is folded in two or three for use.

In the central absorbent portion5, since the through-air bonded nonwoven fabric is disposed between the central absorbent layer4A, which is formed of hydrophilic fibers such as pulp or a mixture of hydrophilic fibers and absorbent polymer and wrapped in a hydrophilic paper, and the topsheet3, menstrual blood applied to the topsheet3in the central absorbent portion5can be passed through the topsheet3, passed through the through-air bonded nonwoven fabric due to its own weight via voids between fibers, and then absorbed by the central absorbent layer4A. Accordingly, the absorption rate of repeatedly applied menstrual blood can be increased, and the topsheet3can be easily kept dry. In addition, since the through-air bonded nonwoven fabric is highly resilient, the central absorbent portion5itself can produce some lateral resilience when the central absorbent portion5is compressed laterally to decrease its width as shown inFIGS. 4 and 5.

In the resilient portions6,6, the through-air bonded nonwoven fabric is held between the backsheet2and the topsheet3, while being compressed together with the resilient layers4B, which is formed by wrapping a layer of pulp or a layer of pulp and absorbent polymer in a hydrophilic paper. Accordingly, the resiliency of the resilient portions6,6can be improved more.

In the first compressed portions11, the through-air bonded nonwoven fabric is heated under pressure together with the absorbent layer, so that the synthetic fibers constituting the through-air bonded nonwoven fabric are thermally fused. Therefore, the first compressed portions11can be maintained in the compressed state, without causing the problem of restoration of the first compressed portions11from the compressed and fixed state upon contact with menstrual blood. Accordingly, the density inside the resilient portions6can be kept high at all times.

It is more preferred that the through-air bonded nonwoven fabric is present also in the second compressed portions12.

Here, the nonwoven fabric of synthetic fibers should not construed as limited to the through-air bonded nonwoven fabric, but different nonwoven fabrics such as spunbonded nonwoven fabric, meltblown nonwoven fabric and the like may be provided in the resilient portions6, the first compressed portions11and the second compressed portions12.

FIG. 7is a half sectional view showing a sanitary napkin1B according to a third embodiment of the present invention.

The structure of the sanitary napkin1B is similar to that ofFIG. 1, except that reinforcing members23are provided in the resilient portions6,6together with the resilient layers4B,4B. The reinforcing members23have a higher density and a higher stiffness than the central absorbent layer4A and the side absorbent layers4C, and for example, may be a foamed resin material such as foamed urethane resin, an air-laid nonwoven fabric in which pulp and synthetic fibers are thermally fusion-bonded together or fixed together with a binder, or a natural or synthetic rubber in the shape of a rod or plate. With the reinforcing members23thus provided, resiliency of the resilient portions6can be improved more.

Here, the foamed urethane resin for the reinforcing members23may be treated to be hydrophilic and disposed to extend continuously inside the central absorbent portion5, the first compressed portions11, the second compressed portions12and the resilient portions6.

In the present invention, it is also possible to eliminate the absorbent layer such as pulp from the resilient portions6,6to leave the reinforcing members23alone between the backsheet2and the topsheet3.

FIG. 8Ais a top plan view showing a sanitary napkin1C according to a fourth embodiment of the present invention.

In the sanitary napkin1C, compressed portions10B are formed in a similar pattern to the compressed potions10ofFIG. 1. The compressed portions10B comprise first compressed portion11B,11B, second compressed portions12B,12B, lateral compressed portions13B,13B, forwardly extending compressed portions14B,14B and rearwardly extending compressed portions15B,15B. However, the compressed portions10B are not formed as continuously extending compressed grooves but as compressed dots that are arranged at spaced intervals along the pattern.

The compressed portions10B are formed such that the topsheet3and the absorbent layer4are heated under pressure only at the dots to have a high density. It should be noted that neither heat nor pressure is applied to locations between adjacent compressed dots when these compressed dots are formed with embossing projections of a dot pattern.

In the sanitary napkin1C, high-density resilient portions6B,6B are formed between the first compressed portions11B,11B and the second compressed portions12B,12B that are formed as rows of compressed dots. In the resilient portions6B,6B, since the restricting force due to the compressed portions11B and12B of the compressed dots is weak, there is a limit to compressing the absorbent layer such as pulp to a high density only with the formation of the compressed portions. In this embodiment, therefore, it is desirable to use previously compression-molded pulp or the like for the resilient layers4B in the resilient portions6B,6B. It is also desirable to use the reinforcing members23, as shown inFIG. 7.

The compressed dots may be in a circular shape, as shown inFIGS. 8A and 8B, or the compressed dots may be in the shape of a longitudinally elongated short line, as shown inFIG. 8C. Preferably, the compressed dots constituting the first compressed portions11B and the compressed dots constituting the second compressed portions12B are staggered so that intermediate portions that are left uncompressed and unheated between adjacent compressed dots of the first compressed portions11B do not overlap laterally (in the X-direction) with intermediate portions that are left uncompressed and unheated between adjacent compressed dots of the second compressed portions12B, as shown inFIGS. 8B and 8C.

With the compressed dots being thus staggered, when menstrual blood applied to the central absorbent portion5is laterally diffused along the topsheet3and the absorbent layer, the compressed dots can function as a labyrinth against the lateral migration of the menstrual blood, effectively inhibiting the menstrual blood from migrating to the side portions7,7.

Here, one of the first and second compressed portions may be formed as compressed grooves like the compressed portions10ofFIG. 1, while the other may be formed as rows of compressed dots, as shown in Figs.8A,8B and8C. For example, it is possible that the first compressed portions, the lateral compressed portions, the forwardly extending compressed portions and the rearwardly extending compressed portions are all formed as compressed grooves, while only the second compressed portions are formed as rows of compressed dots. It is also possible that the second compressed portions are formed as compressed grooves, while the first compressed portions are formed as rows of compressed dots wholly or only at regions confronted by the second compressed portions. In these cases, the lateral compressed portions, the forwardly extending compressed portions and the rearwardly extending compressed portions may be formed either as compressed grooves or as rows of compressed dots.

However, it is preferred that the first compressed portions closer to the longitudinal centerline Oy-Oy are formed as compressed grooves while the second compressed portions are formed as rows of compressed dots. In this case, the menstrual blood applied to the central absorbent portion5can be certainly inhibited from migrating to the resilient portions6,6.

In the case where the compressed portions are formed as rows of compressed dots, as set forth above, since uncompressed portions between adjacent compressed dots can easily be bent in the longitudinal direction, the front and rear portions of the sanitary napkin can easily be bent and deformed to conform to the abdomen and buttocks, respectively. Particularly when the compressed dots are staggered, as shown inFIGS. 8B and 8C, the effect of bending can be enhanced without increasing the bending stiffiess of the compressed portions.

In the case where short line-shaped compressed dots are formed, as shown inFIG. 8C, it is preferred that the short line-shaped compressed dots have a length of about 10 to 20 mm and intermediate portions (uncompressed portions) between short line-shaped compressed dots adjacent each other in the longitudinal direction have a length of about 5 to 10 mm. Here, the individual short line-shaped compressed dots may be formed by alternating the high-density compressed portions10awith the medium-density compressed portions10b. The compressed portions shown inFIG. 1may be interrupted at an arbitrary position.

Referring toFIG. 9throughFIG. 13, yet other embodiments will be described hereinbelow. The compressed portions in the first through fourth embodiments are formed in the same or similar pattern, but compressed portions in the embodiments shown inFIG. 9throughFIG. 13are formed in patterns different from that of the first through fourth embodiments.

Regarding the constructions but for the patterns of the compressed portions, however, the constructions shown in the first through fourth embodiments may, of course, be selectively adopted for the embodiments shown inFIG. 9throughFIG. 13. Hereinbelow, therefore, described will be only the difference in pattern of the compressed portions, while the detailed description of the other portions will be omitted by designating them by the reference numerals common to the individual embodiments.

FIG. 9is a top plan view showing a sanitary napkin1E according to a fifth embodiment of the present invention.

Compressed portions10E provided in the sanitary napkin1E ofFIG. 9do not include the lateral compressed portions13,13ofFIG. 1, so that forwardly extending compressed portions14E,14E and rearwardly extending compressed portions15E,15E are continuously extended forwardly and rearwardly from first compressed portions11E,11E in the shape of an arcuate line. The region between the first compressed portions11E,11E is the central absorbent portion5. Second compressed portions12E,12E are disposed outside the central absorbent portion5.

The second compressed portions12E,12E are also formed in the shape of an arcuate line and spaced a constant distance apart from the first compressed portions11E,11E.

Also in this embodiment, the resilient portions6,6can exhibit sufficient resiliency in the deformed state ofFIGS. 4 and 5. In addition, since menstrual blood applied to the absorbent layer can diffuse from the central absorbent portion5between the first compressed portions11E,11E into the portion between the forwardly extending compressed portions14E,14E and the portion between the rearwardly extending compressed portions15E,15E, the length of the sanitary napkin1E can be fully exploited when a large amount of menstrual blood is applied.

FIG. 10is a top plan view showing a sanitary napkin1F according to a sixth embodiment of the present invention.

The sanitary napkin1F is elongated and its width between the right side edge1aand the left side edge1bis increased at its rear portion to provide what is called hip-guard.

In this embodiment, first rear compressed portions15F,15F are extended rearwardly from first compressed portions11F,11F in such a manner that they gradually approach each other toward the rear end edge1dand are connected to each other inside the rear end edge1dthrough a connecting compressed portion17F in the shape of a curved line.

Outside the first rear compressed portions15F,15F, moreover, second rear compressed portions18F,18F are provided and connected to each other inside the rear end edge1dthrough a connecting compressed portion19F in the shape of a curved line. The second rear compressed portions18F,18F are also provided with portions that gradually approach each other toward the rear end edge1d.

In this embodiment, the region surrounded by the first compressed portions11F,11F and lateral compressed portion13F is a central absorbent portion5F, while the region surrounded by the first rear compressed portions15F,15F and the connecting compressed portion17F is a rear central absorbent portion5G. The bulky central absorbent layer4A continuously extends over the central absorbent portion5F and the rear central absorbent portion5G, between the topsheet3and the backsheet2. In the central absorbent portion5F and the rear central absorbent portion5G, the density and basis weight of the central absorbent layer4A are almost uniform.

Between the first rear compressed portions15F,15F and the second rear compressed portions18F,18F, moreover, there are provided rear resilient portions6F,6F, in which the absorbent layer (resilient layer) between the topsheet3and the backsheet2has a higher density than the central absorbent layer4A in the rear central absorbent portion5G. The density of the absorbent layer in the rear resilient portions6F,6F is equal to or slightly lower than that in the resilient portions6,6and higher than that of the central absorbent layer4A.

As shown inFIG. 10, boundary portions between the first rear compressed portions15F,15F and the first compressed portions11F,11F are curved away from the longitudinal centerline Oy-Oy, so that the central absorbent layer4A is widened at these boundary portions. The first rear compressed portions15F,15F gradually approach each other as they extend from the boundary portions toward the rear end edge1d, while the first compressed portions11F,11F also gradually approach each other as they extend from the boundary portions to the lateral reference line Ox-Ox.

On right and left sides of the skin surface of the sanitary napkin1F, the liquid-impermeable sheets20,20and the leakage preventing walls21,21formed of the liquid-impermeable sheets20,20are provided. The leakage preventing walls21,21are of the same construction as those shown inFIG. 1except for dimensions. The boundary line between the bonded region and the unbonded region in the first panel21aincludes the intermediate boundary line22a, the front boundary line22band the rear boundary line22c, wherein24aindicates the front rising point of the leakage preventing wall21, while24bindicates the rear rising point of the leakage preventing wall21.

Also in this embodiment, the front rising point24ais in proximity to the front end of the resilient portion6, and the least straight-line distance between the rising point24aand the front end12aof the second compressed portion12F is 45 mm or less, preferably 40 mm or less, more preferably 25 mm or less.

Likewise, the rear rising point24bis in proximity to the front end of the rear resilient portion6F, and the distance between the rising point24band a front end18G of the second rear compressed portion18F is 45 mm or less. In case of the sanitary napkin1F ofFIG. 10that is long and suitable for night-time use with the first rear compressed portions15F, the second rear compressed portions18F and the hip-guard, however, the hip-guard intended to contact the buttocks is easily twisted or distorted. Accordingly, the least straight-line distance between the rear rising point24bof the leakage preventing wall21and the front end18G of the second rear compressed portion18F is preferably 20 mm or less.

When the long sanitary napkin1F is worn as attached to the inner side of the groin piece25of the undergarment, the lateral reference line Ox-Ox can match the longitudinal nearly center of the vaginal opening.

When the compressive force F is applied to the vicinity of the lateral reference line Ox-Ox from the thighs, therefore, the sanitary napkin1F at this portion can be deformed as shown inFIGS. 4 and 5, and then, when the compressive force F is relieved, the sanitary napkin1F can be restored from the deformed state ofFIGS. 4 and 5to its original state due to the resiliency of the resilient portions6,6.

Here, the rear portion of the sanitary napkin1F is brought into contact with the buttocks so that the rear central absorbent portion5G may fit in the cleft of the buttocks. Since the rear resilient portions6F,6F are provided on both sides of the rear central absorbent portion5G, the rear portion is hardly deformed even if the sanitary napkin1F is subjected to an excessive pressure from the wearer's body or undergarment caused by change of wearer's position (posture) or can be easily restored after deformation, so that the rear central absorbent portion5G can be certainly kept in close contact with the wearer's body.

Moreover, since the front rising point24aof the leakage preventing wall21is in proximity to the resilient portion6and the rear rising point24bis in proximity to the rear resilient portion6F, the positions of the rising points24aand24bcan be stabilized during wear, thereby preventing the leakage preventing wall21from twisting or falling down on the central absorbent portion5F and the rear central absorbent portion5G.

In case where the sanitary napkin1F is worn together with a sanitary panty in which an elastic member is provided from a groin piece to a back body to extend along the cleft of the wearer's buttocks, the rear central absorbent portion5G is pushed into the cleft of the buttocks due to a force of the elastic member. At this time, since the first rear compressed portions15F,15F and the second rear compressed portions18F,18F are provided on two sides of the rear central absorbent portion5G and can individually serve as a flexible hinge, the rear central absorbent portion5G subjected to the pushing force from the undergarment can be easily brought into close contact with the buttocks.

FIG. 11is a top plan view showing a sanitary napkin1G according to a seventh embodiment of the present invention.

Although a hip-guard is provided at its rear portion, the sanitary napkin1G ofFIG. 11is of a slightly shorter longitudinal dimension than the sanitary napkin1F ofFIG. 10.

The sanitary napkin1G has compressed portions10G that are formed in the substantially same pattern as the compressed potions10F ofFIG. 10, except that the second compressed portions12F,12F are continued to the second rear compressed portions18F,18F. Also in this sanitary napkin1G, since the resilient portions6,6are provided on two sides of the central absorbent portion5F, sufficient resilience can be produced against an external deforming force.

Here, the straight-line distance between the front rising point24aof the leakage preventing wall21and the front end12aof the second compressed portion12F is 45 mm or less, preferably 40 mm or less, more preferably 25 mm or less. The least straight-line distance between the rear rising point24band the second rear compressed portion18F is also45mm or less, preferably 25 mm or less. In the embodiment ofFIG. 11where the rising point24bis located between the second rear compressed portion18F and the right side edge1a, however, the straight-line distance may be considerably decreased, for example, to 15 mm or less.

Accordingly, the individual rising points24aand24b, particularly the rear rising point24b, can be certainly reinforced by the rear resilient portion6F, thereby preventing the leakage preventing wall21from twisting or falling down.

FIG. 12is a top plan view showing a sanitary napkin1H according to an eighth embodiment of the present invention.

The structure of the sanitary napkin1H is similar to that of the sanitary napkin1shown inFIG. 1, except that the wings18are eliminated.

The sanitary napkin1H ofFIG. 12has compressed portions10H comprising first compressed portion11H,11H that extend in the shape of an arcuate line and second compressed portions12H,12H that also extend in the shape of an arcuate line outside the former, wherein the first compressed portion11H,1H are spaced a constant distance apart from the second compressed portions12H,12H. The region between the first compressed portion11H,11H is a central absorbent portion5H, while the regions between the first compressed portion11H,11H and the second compressed portions12H,12H are resilient portions6H,6H.

The second compressed portions12H,12H are connected to each other through lateral compressed portions13H,13H provided at front and rear portions. Therefore, the first compressed portion11H,11H and the resilient portions6H,6H are located inside the region surrounded by the second compressed portions12H,12H and the lateral compressed portions13H,13H.

Furthermore, forwardly extending compressed portions14H,14H and rearwardly extending compressed portions15H,15H are formed to extend continuously from the second compressed portions12H,12H.

Also in the sanitary napkin1H, the resilient portions6H,6H can produce sufficient lateral resilience.

In this embodiment, since the region surrounded by the second compressed portions12H,12H and the lateral compressed portions13H,13H has a larger area than the central absorbent portion5H, liquid absorption capacity of the surrounded region can be made large. In addition, since diffusion of menstrual blood applied to the resilient portions6H,6H between the first compressed portion11H,11H and the second compressed portions12H,12H can be limited in the surrounded region, leakage of menstrual blood from the sanitary napkin1H can be prevented easily.

FIG. 13is a top plan view showing a sanitary napkin1J according to a ninth embodiment of the present invention.

The sanitary napkin1J has compressed portions10J whose pattern is slightly changed from that in the sanitary napkin1E ofFIG. 9. In this embodiment, forwardly extending compressed portions14J,14J and rearwardly extending compressed portions15J,15J are continuously extended forwardly and rearwardly from second compressed portions12J,12J. On the other hand, first compressed portions11J,11J are provided in the region between the second compressed portions12J,12J. The region between the first compressed portions11J,11J is a central absorbent portion5J.

Also in this embodiment, sufficient lateral resilience against compression can be produced by the action of resilient portions6J,6J. In addition, since region outside the central absorbent portion5J is positioned between the second compressed portions12J,12J, the forwardly extending compressed portions14J,14J and the rearwardly extending compressed portions15J,15J over a long range in the longitudinal direction, menstrual blood adhered to the resilient portions6J,6J can be diffused in the longitudinal direction of the sanitary napkin1J, thereby improving the effect of preventing lateral leakage.

Next, a method for manufacturing the sanitary napkin will be described.

Hereinafter a method for manufacturing the sanitary napkin1shown inFIG. 1andFIGS. 2A and 2Bwill be described, but the sanitary napkins according to the other embodiments can be manufactured in a similar manner by changing the pattern of the compressed portions or changing the materials to be disposed between the first compressed portion11and the second compressed portion12.

In the manufacturing method of the sanitary napkin1, at first, the absorbent layer4and the topsheet3are stacked one upon another and optionally bonded to each other. Then, the stack is pressed with the pressure member having an embossed pattern from the side of the topsheet3, to thereby form the compressed portions10. Subsequently, the backsheet2is laid on and bonded to the stack. Here, it is possible to emboss only the absorbent layer4and then hold it between the backsheet2and the topsheet3. The embossing may be performed from the side of the exterior surface (garment surface) of the absorbent layer4or from both sides. In the followings, however, the case where the stack of the absorbent layer4and the topsheet3is embossed from the side of the topsheet3will be described.

FIG. 14Ais a plan view showing a portion of a pressure member100from the side of a pressing surface thereof, andFIG. 14Bis a sectional view taken along lone B-B ofFIG. 14A.

The pressure member100has an embossing projection110whose pattern can be transferred to the stack as the compressed portions10shown inFIG. 1. InFIG. 14A, illustrated is only a portion of the embossing projection110that forms the first and second compressed portions11and12in the vicinity of the lateral reference line Ox-Ox ofFIG. 1.

InFIGS. 14A and 14B, a first base115for facing the central absorbent portion5of the sanitary napkin1is provided on the left side of the embossing projection110, while a second base117for facing the side portion7is provided on the right side. Here, the depth from the top of the embossing projection110to the first base115is indicated by D2, while the depth form the top to the second base117is indicated by D3. The depths D2and D3may be equal or the first base115may be made deeper because it is intended to face the central absorbent portion5that is relatively thick.

FIGS. 14A and 14Bshow a first projection111for forming the first compressed portion11and a second projection112for forming the second compressed portion12. Between the first projection111and the second projection112, as shown inFIG. 14B, there is formed a recess116for compressing the absorbent layer at a location between the first compressed portion11and the second compressed portion12. In this embodiment, the resilient portion6is formed by the recess116. The depth D1from the top to the bottom of the recess116is sufficiently smaller than the depths D2and D3.

The first projection111has a pressing portion111aat the tip thereof, and inclined surfaces111b,111bthat are inclined away from the top are formed at both sides thereof Likewise, the second projection112has a pressing portion112aat the tip thereof, and inclined surfaces112b,112bare formed in the same manner. Here, the inclined surfaces111band112bmay be steep slopes continuing to the bottom of the recess116.

Along the pressing portions111aand112a, pressing surfaces110afor forming the high-density compressed portions10aalternate with shallow grooves110bfor forming the medium-density compressed portions10b. The pressing surfaces110aand the shallow grooves110bare formed in the same pattern as the high-density compressed portions10aand the medium-density compressed portions10b.

On the other hand, projections for forming portions of the first compressed portions11that are not confronted by the second compressed portions12inFIG. 1, projections for forming the lateral compressed portions13, projections for forming the forwardly extending compressed portions14and projections for forming the rearwardly extending compressed portions15are formed such that only the first projection111rises from the first and second bases115and117, without having the second projection112alongside of the first projection111as inFIGS. 14A and 14B.

After stacking the absorbent layer4and the topsheet3one upon another and optionally bonding them to each other, the pressure member100ofFIGS. 14A and 14Bis applied to the surface of the topsheet3while another pressure member having a smooth surface is applied to the exterior surface of the absorbent layer4, so that the absorbent layer4and the topsheet3are pressed with the two pressure members. Here, the pressure members may be heated for pressing, if necessary. As a result, the compressed portions10are formed in the stack, as shown inFIG. 1.

At this time, since the absorbent layer4is pressed with the recess116of the depth D1, the absorbent layer is highly compressed at a location between the first compressed portion11and the second compressed portion12. Here, the highly compressed absorbent layer is restricted by the topsheet3between the first compressed portion11and the second compressed portion12.

On the other hand, the central absorbent portion5is not substantially pressed or hardly pressed with the first base115. Likewise, the side portion7is not substantially pressed or hardly pressed with the second base117. Thus, the absorbent layer can be highly compressed at a location between the first compressed portion11and the second compressed portion12to have a density sufficiently higher than those in the central absorbent portion5and the side portions7.

In the foregoing embodiments, the highly compressed absorbent layer is the resilient layer4B. The highly compressed absorbent layer formed between the compressed portions11and12can serve not only as the resilient layer4B but also as a support member for supporting the central absorbent portion5from below and bringing it into close contact with the vaginal opening when the sanitary napkin1is in the deformed state ofFIG. 4.

It should be noted that the pressure member100and the pressure member having a smooth surface may be constructed as surface structures of rolls facing each other or as flat pressure members. With the recess116thus provided, the absorbent layer may be highly compressed at a location between the first compressed portion11B and the second compressed portion12B that are formed of compressed dots, as shown inFIG. 8.

According to the present invention, as has been described hereinabove, the ability to laterally restore the central absorbent portion when a lateral compressive force applied thereto is relieved, can be improved. In addition, the absorbent article can be easily restored from other deformations such as twisting. Accordingly, it can be kept in close contact with the excretory part of the wearer's body at all times, thereby preventing lateral leakage of discharged liquid.

Although the present invention has been illustrated and described with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omission and additions may be made therein and thereto, without departing from the spirit and scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiments set out above but to include all possible embodiments which can be embodied within a scope encompassed and equivalent thereof with respect to the feature set out in the appended claims.