JP7567132B2 - Absorbent articles - Google Patents

Description

The present invention relates to an absorbent article.

In absorbent articles such as sanitary napkins, panty liners, and incontinence pads, various configurations have been considered to prevent side leakage of bodily fluids. For example, Patent Document 1 discloses a sanitary napkin with a pair of three-dimensional gathers formed on both sides along the longitudinal direction of a vertically elongated absorbent body. The three-dimensional gathers include a side sheet provided on the skin-facing side of the side of the absorbent body, and an elastic member fixed in a stretched state to the side sheet.

JP 2013-85829 A

The structure of three-dimensional gathers is relatively complex, and in many cases, a thread-like elastic member such as rubber thread is intermittently bonded to the side sheet with an adhesive or the like. However, depending on the amount of adhesive applied, the application position, etc., the elastic member may not be firmly fixed to the side sheet. In such cases, depending on the wearing conditions, excessive force may be applied in the planar direction of the three-dimensional gathers, causing the elastic member to partially come off the side sheet, and the gathers may not be able to stand up and may not be able to fully prevent side leakage. Therefore, there is a demand for a simpler means of preventing side leakage to replace three-dimensional gathers.

One aspect of the present invention aims to provide an absorbent article equipped with a side leakage prevention means having a simpler and more robust structure.

The first aspect of the present invention is an absorbent article comprising an elongated main body having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body provided between the top sheet and the back sheet, and a non-stretchable side leakage prevention sheet arranged along a front-to-rear direction perpendicular to the width direction on the top sheet side of each end of the width direction of the main body, the side leakage prevention sheet being folded back on the inside in the width direction to form an upper layer and a lower layer, the front joint portion being formed by joining the upper layer and the lower layer at the front, the rear joint portion being joined the upper layer and the lower layer at the rear, and a non-joint portion between the front joint portion and the rear joint portion where the upper layer and the lower layer are not joined.

According to the first aspect, the absorbent article is provided with a non-stretchable side leakage prevention sheet in which the upper and lower layers are formed by folding back the inner side in the width direction, and the upper and lower layers are joined at the front and rear, but not joined in between. Therefore, while the absorbent article is being worn, the upper layer can move away from the lower layer at the non-jointed portion where the upper and lower layers are not joined. In addition, since the upper and lower layers of the side leakage prevention sheet are formed by folding back the sheet, stress is generated in the side leakage prevention sheet to return to the state before it was folded back. Here, since the lower layer is fixed to the main body and the folded back position of the side leakage prevention sheet is on the inner side in the width direction, the upper layer of the side leakage prevention sheet is easily lifted toward the skin from the inner edge in the width direction. As a result, the side leakage prevention sheet can function as a side leakage prevention means that prevents bodily fluids from flowing outward in the width direction.

The non-stretchable side leakage prevention sheet in this embodiment has a simple structure and is robust. Conventional side leakage prevention means, such as three-dimensional gathers, may not stand up if excessive shear force is applied in the planar direction of the sheet, causing the elastic member fixed in a stretched state to break away from the sheet, resulting in a loss of adhesion between the sheet and the three-dimensional gathers, and the side leakage prevention function may be compromised. In contrast, in this embodiment, the side leakage prevention sheet has a simple structure formed by folding the sheet without using elastic or stretchable materials, so that the basic structure is not easily damaged even if excessive force is applied to the side leakage prevention sheet.

In a second aspect of the present invention, the bending resistance of the side leakage prevention sheet is 100 mm or more.

According to the second aspect, since the side leakage prevention sheet has a predetermined bending resistance, the force generated in the folded side leakage prevention sheet to return to the state before being folded is large. Therefore, the action of the upper layer formed by folding and lifting away from the lower layer can be further increased. Therefore, the side leakage prevention function can be improved.

In a third aspect of the present invention, the side leakage prevention sheet includes paper.

According to the third aspect, the side leakage prevention sheet contains paper, which reduces the burden on the environment during the manufacture or disposal of the absorbent article.

In a fourth aspect of the present invention, the side leakage prevention sheet is made of a laminated sheet formed by stacking a plurality of sheets, and the laminated sheet includes a core sheet having a bending resistance of 100 mm or more and a covering sheet that covers the core sheet.

According to the fourth aspect, the side leakage prevention sheet is a laminated sheet, which is a combination of a core sheet with a relatively high bending resistance and a cover sheet that covers the core sheet. Therefore, it is possible to obtain a side leakage prevention sheet that is covered with another material having a function according to the application while ensuring the appropriate bending resistance to exert the side leakage prevention function. For example, by using a soft material that feels good against the skin as the cover sheet, it is possible to obtain an additional pleasant feel against the skin while ensuring the side leakage prevention function.

In the fifth aspect of the present invention, the upper layer has a plurality of upper layer recesses recessed from the top sheet side to the back sheet side.

According to the fifth aspect, by providing a recess in the upper layer of the lateral leakage prevention sheet, when bodily fluids flow over the lateral leakage prevention sheet to the outside in the width direction and reach the surface of the lateral leakage prevention sheet, the recess can capture the bodily fluids. This improves the lateral leakage prevention function of the lateral leakage prevention sheet.

In a sixth aspect of the present invention, the lower layer is formed with a plurality of lower layer convex portions that protrude from the back sheet side to the top sheet side, and the upper layer concave portions and the lower layer convex portions overlap.

According to the sixth aspect, the upper layer recess and the lower layer recess overlap, so that a space is formed between the upper layer and the lower layer, and the upper layer and the lower layer are easily separated. Therefore, the upper layer is easily lifted when the absorbent article is worn, and the side leakage prevention function of the side leakage prevention sheet can be improved.

According to one aspect of the present invention, it is possible to provide an absorbent article equipped with a side leakage prevention means having a simpler and more robust structure.

1 is a plan view of an absorbent article according to one embodiment of the present invention. 2 is a cross-sectional view taken along line II in FIG. 1. 2 is a cross-sectional view taken along line II-II of FIG. 1. FIG. 11 is a plan view of a modified example of the absorbent article. FIG. 5 is a partially enlarged cross-sectional view taken along line III-III in FIG. 4. 13 shows a modified example of the upper layer recess. FIG. 2 is an enlarged cross-sectional view of an example of a lateral leakage prevention sheet which is a laminated sheet. FIG. 13 is a plan view of another modified example of the absorbent article.

The following describes an embodiment of the present invention with reference to the drawings. In each drawing, unless otherwise specified, the same or corresponding configurations may be given the same reference numerals and the description may be omitted. In addition, the drawings are schematic to facilitate understanding of the invention.

(Basic structure of absorbent article)
First, the basic structure of an absorbent article according to an embodiment of the present invention will be described using a sanitary napkin as an example. Fig. 1 shows a plan view of an absorbent article 1. Fig. 2 shows a cross-sectional view taken along line II in Fig. 1, and Fig. 3 shows a cross-sectional view taken along line II-II in Fig. 1.

As shown in Figures 1 to 3, the absorbent article 1 has a flat main body (absorbent article main body) 8 that includes a liquid-impermeable back sheet 2, a liquid-permeable top sheet 3, and an absorbent body 4 disposed between the back sheet 2 and the top sheet 3. When the absorbent article 1 is worn, the top sheet 3 side faces the skin (skin side or front side), and the back sheet 2 side faces the underwear (underwear side or back side). The plan view in Figure 1 is a view of the absorbent article 1 as seen from the skin side.

In addition, in this specification, as shown in Figure 1, the direction corresponding to the front-rear direction of the wearer's body when the absorbent article 1 is worn is defined as the front-rear direction D1 of the absorbent article 1, and the direction perpendicular to this front-rear direction D1 is defined as the width direction D2 of the absorbent article 1. The main body 8 has an elongated shape that is long in the front-rear direction D1 in a plan view, has a predetermined length in the front-rear direction D1, and has a predetermined width D2 perpendicular to the front-rear direction D1.

In the embodiment shown in FIG. 1, the main body 8 has a shape in plan view that is approximately line-symmetrical with respect to a center line (front-rear center line) CL extending in the front-rear direction D1, but the shape of the main body 8 does not have to be line-symmetrical. The shape of the absorbent article 1 may also be approximately line-symmetrical with respect to the front-rear center line CL. Furthermore, the configurations of the absorbent article 1 and the main body 8 other than their shapes (including the thickness and density of the absorbent body 4, the size and position of the compressed grooves, the shape and size of the wings and flaps, etc.) may be approximately symmetrical or asymmetrical with respect to the center line CL as the axis of symmetry.

The absorbent article 1 has an intermediate region M that faces mainly the crotch of the wearer when worn, a front region F adjacent to the front of the intermediate region M, and a rear region R adjacent to the rear of the intermediate region M. The intermediate region M includes a body fluid discharge port facing region Q. The body fluid discharge port facing region Q is a region that faces the body fluid discharge port of the wearer when worn. The center of the body fluid discharge port facing region Q is located on the longitudinal centerline CL, and its length (length in the front-rear direction D1) may be about 10 to 50 mm, and its width (length in the width direction D2) may be about 5 to 40 mm. In FIG. 1, the body fluid discharge port facing region Q is depicted as an ellipse facing the vaginal opening. However, the above-mentioned size and shape of the body fluid discharge port facing region Q are merely examples for explaining the absorbent article 1 according to this embodiment.

The middle region M may have a pair of wings WG, WG that protrude outward in the front-to-rear direction D2. When worn, the wings WG, WG can be folded back and attached to the undergarment, thereby allowing the absorbent article 1 to be securely fixed to the undergarment. The front region F may be the region from approximately the position where the front of the wings WG start to the front edge, and the rear region R may be the region from the position where the rear of the wings WG start to the rear edge. The absorbent article 1 may have a form without the wings WG, WG.

The back sheet 2 may be a sheet having at least water impermeability, for example, a sheet made of an olefin resin such as polyethylene or polypropylene. Alternatively, a laminated nonwoven fabric in which a nonwoven fabric is laminated on a polyethylene sheet or the like, or a laminated sheet of nonwoven fabric in which a waterproof film is interposed to ensure substantial liquid impermeability, may be used. Furthermore, it is more preferable to use a sheet having moisture permeability from the viewpoint of preventing stuffiness. As such a water impermeable/moisture permeable sheet material, a microporous sheet obtained by melt-kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene to form a sheet and then stretching the sheet in a uniaxial or biaxial direction may be used. The back sheet 2 may be a sheet having the same outer shape as the outer shape of the absorbent article 1.

The top sheet 3 can be a liquid-permeable sheet that allows bodily fluids such as menstrual blood, vaginal discharge, and urine to pass through quickly. As the top sheet 3, a nonwoven fabric with or without holes, a porous plastic sheet, or the like is preferably used. As the material fibers constituting the nonwoven fabric, for example, olefins such as polyethylene and polypropylene, synthetic fibers such as polyester and polyamide, regenerated fibers such as rayon and cupra, and blended fibers thereof, and natural fibers such as cotton can be used alone or in combination of two or more kinds. In addition, examples of processing methods for nonwoven fabric include the spunlace method, the spunbond method, the thermal bond method, the meltblown method, and the needle punch method. Among these processing methods, the spunlace method is preferred in that it can produce a nonwoven fabric that is flexible, and the spunbond method is preferred in that it can produce a nonwoven fabric that is rich in drapeability, and the thermal bond method is preferred in that it can produce a nonwoven fabric that is bulky and soft. In addition, composite fibers such as core-sheath type fibers, side-by-side type fibers, and split type fibers, which have a fiber with a high melting point as the core and a fiber with a low melting point as the sheath, can also be used.

The absorbent body 4 is not limited to any material that can absorb and retain bodily fluids, but preferably contains cotton-like pulp and a water-absorbing polymer. As the water-absorbing polymer, superabsorbent polymer granular powder (superabsorbent polymer (SAP)), superabsorbent polymer fiber (superabsorbent fiber (SAF)), and combinations thereof can be used. As the pulp, chemical pulp obtained from wood, cellulose fibers such as dissolving pulp, and artificial cellulose fibers such as rayon and acetate can be used. As the raw material for chemical pulp, broadleaf wood and softwood are used, but softwood is preferably used because of its long fiber length.

Synthetic fibers may also be mixed into the absorbent 4. Synthetic fibers include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon, and copolymers thereof. Two of these may also be mixed and used. Composite fibers such as core-sheath fibers with a high melting point fiber as the core and a low melting point fiber as the sheath, side-by-side fibers, and split fibers may also be used. Hydrophobic fibers may also be surface-treated with a hydrophilizing agent to give them affinity for body fluids. The absorbent 4 is preferably manufactured by stacking or air-laid methods.

The absorbent body 4 may have a shape and size such that it does not protrude from the back sheet 2 and the top sheet 3 in the front-rear direction D1. At both ends in the front-rear direction D1, the edges of the back sheet 2 and the edges of the top sheet 3 may be joined by adhesive, heat sealing, or the like. The absorbent body 4 may also have a shape and size such that it does not protrude from at least the back sheet 2 in the width direction D2.

The absorbent article 1 shown in Figures 1 to 3 may additionally have a pair of side nonwoven fabrics arranged along the front-rear direction D1 on the top sheet 3 side of both ends of the main body 8 in the width direction D2. The side nonwoven fabrics may protrude outward in the width direction D2 in the middle region M and be joined to the back sheet 2 that also protrudes in the width direction D2 in the middle region M to form the wings WG, WG described above. The side nonwoven fabrics may be provided under the side leakage prevention sheet 10 described below.

(Side leakage prevention sheet)
In the absorbent article 1 according to this embodiment, non-stretchable side leakage prevention sheets 10, 10 extending along the front-rear direction D1 are disposed on both sides of the main body 8, i.e., on the top sheet side of both ends in the width direction D2. In this specification, "non-stretchable" refers to the property of not stretching or barely stretching when the sheet is pulled by hand by a user of the absorbent article.

As shown in FIG. 1, the side leakage prevention sheets 10, 10 preferably extend from the front end to the rear end of the absorbent article 1 or main body 8, i.e., over the entire front-rear direction D1. As long as the side leakage prevention function is not impaired, the sheets may extend in the front-rear direction D1 over a portion of the absorbent article 1 or main body 8, for example, over an area including at least the middle region M, and preferably over a range including the middle region M and a portion of the rear region R.

The side leakage prevention sheet 10 may be joined to the top sheet 3, or, if the top sheet 3 does not cover the ends of the absorbent body 4 in the width direction D2, it may be joined to the top sheet 3 and the top sheet side of the absorbent body 4. If side nonwoven fabrics are provided on both sides of the main body 8 (both ends in the width direction D2), the side leakage prevention sheets 10, 10 may be joined entirely or partially to the side nonwoven fabrics.

2 and 3, the side leakage prevention sheet 10 is formed by folding back a single sheet at a fold line 15 on the inside in the width direction D2. By folding back at this fold line 15, the side leakage prevention sheet 10 has a two-layer structure consisting of an upper layer 13 and a lower layer 14. The lower layer 14 is joined and fixed to the main body 8 in the front-to-rear direction D1. On the other hand, the upper layer 13 is joined to the lower layer 14 only at the front and rear. More specifically, as shown in FIG. 1, the side leakage prevention sheet 10 has a front joint portion 11f where the upper layer 13 and the lower layer 14 are joined at the front, a rear joint portion 11r where the upper layer 13 and the lower layer 14 are joined at the rear, and a non-joint portion 12 between the front joint portion 11f and the rear joint portion 11r where the upper layer 13 and the lower layer 14 are not joined. At the front joint 11f and the rear joint 11r, the upper layer 13 and the lower layer 14 may be joined, for example, with an adhesive AD (Figure 2).

The non-jointed portion 12 is preferably formed at a position and length in the front-rear direction D1 that includes at least the range of the bodily fluid outlet facing portion Q, and is preferably formed to straddle the middle region M in the front-rear direction D1. For example, the length of the non-jointed portion 12 in the front-rear direction D1 may be 100 to 250 mm.

In the non-jointed portion 12 of the side leakage prevention sheet 10, the upper layer 13 is not joined to the lower layer 14, so the upper layer 13 has some freedom of movement. In addition, the two-layer structure of the upper layer 13 and the lower layer 14 is not formed by overlapping two separate layers, but is formed by folding back at the fold line 15, so that the side leakage prevention sheet 10 generates stress that tries to return to the state before it was folded back, that is, the unfolded single-layer state. Therefore, the upper layer 13, which has some freedom of movement, has a tendency to lift upward from the fold line 15, which is the inner edge in the width direction D2, as a base point (arrow in Figure 3). Such a lifted upper layer 13 can block bodily fluids that flow toward the outside in the width direction D2, thereby effectively preventing side leakage.

When wings WG, WG are formed on the absorbent article 1 as shown in Figures 1 to 3, when worn, the main body 8 tends to be pulled toward the back sheet 2 at both ends in the width direction D2, that is, in a direction away from the skin. In contrast, by providing a side leakage prevention sheet 10 in which the upper layer 13 can be lifted toward the skin, as in this embodiment, even if the lower layer 14 is pulled in a direction away from the skin, the upper layer 13 can be lifted closer to the skin without following the lower layer 14. Therefore, this embodiment is suitable for use in absorbent articles with wings WG, WG.

In addition, the side leakage prevention sheet 10 in this embodiment is non-stretchable and does not include an elastic member or a stretchable member. Since elastic members or stretchable members often include synthetic polymers, it is preferable that the side leakage prevention sheet 10 does not include an elastic member or a stretchable member, for example, in consideration of the burden on the environment when the absorbent article 1 is disposed of.

The upper layer 13 does not include an elastic or stretchable member, and is joined to the lower layer 14 at the front joint 11f and the rear joint 11r, so that the degree to which the upper layer 13 is lifted is limited. For example, at the non-jointed portion 12, the upper layer 13 can be lifted to form an angle of 10° to 60° with respect to the lower layer 14. Since the upper layer 13 does not lift significantly with respect to the lower layer 14, the upper layer 13 can make surface contact with the skin near the base of the wearer's foot when the absorbent article 1 is worn. That is, in this embodiment, the outer end 13a of the upper layer 13 in the width direction D2 is unlikely to come into contact with the wearer's skin, and the possibility of the upper layer 13 being crushed by force applied from the outer end 13a of the upper layer 13 in the width direction D2 is reduced.

The side leakage prevention sheet 10 in this embodiment has a simple structure obtained by the simple process of folding as described above. Therefore, manufacturing is not complicated and manufacturing costs can be reduced. Furthermore, if excessive force is applied to the side leakage prevention sheet 10, for example, if a shear force is applied along the surface direction of the side leakage prevention sheet 10, the side leakage prevention function will not be impaired even if the upper layer 13 and the lower layer 14 are slightly misaligned relative to each other in the surface direction. In this way, the side leakage prevention sheet 10 has a simpler and more robust structure than conventional side leakage prevention means.

In addition, it is preferable that the side leakage prevention sheet 10 has a certain degree of rigidity. For example, the bending resistance of the side leakage prevention sheet 10 measured in accordance with the 45° cantilever method described in JIS L1096:2010, 8.21 is preferably 100 mm or more, and more preferably 105 mm or more. When the side leakage prevention sheet 10 has the above bending resistance, the stress of the side leakage prevention sheet 10, which is folded back and arranged, to return to the state before being folded back becomes greater. Therefore, the action of the upper layer 13 formed by folding back and lifting it away from the lower layer 14 becomes greater, and the side leakage prevention function of the side leakage prevention sheet 10 can be improved.

The material constituting the side leakage prevention sheet 10 is not particularly limited, but it is preferable that the side leakage prevention sheet 10 contains a fiber-containing sheet such as paper, nonwoven fabric, woven fabric, knitted fabric, etc. as a main material, and is preferably made of a fiber-containing sheet. In addition, from the viewpoint of reducing the burden on the environment during production and/or disposal, it is preferable that the side leakage prevention sheet 10 contains paper as a main material, and is preferably made of paper. In this specification, paper can refer to a sheet made by gluing plant fibers and other fibers with an adhesive to form a flat plate. In particular, it can refer to a sheet made of plant fibers (pulp) as a main raw material, for example, a sheet containing plant fibers at 50% or more, preferably 80% or more. The type of pulp contained in the paper may include wood pulp, non-wood pulp, and recycled paper pulp, and these may be either mechanical pulp or chemical pulp. Additives may be added to the paper. Furthermore, specific examples of paper used in the side leakage prevention sheet 10 include various types of paper such as Western paper, Japanese paper, processed paper, and synthetic paper. In addition, paper that has traditionally been used for other purposes, such as newsprint, printing paper (including fine paper), writing paper, drawing paper, wrapping paper, tissue paper, miscellaneous paper, etc., can also be used either unprocessed or processed.

The paper used as the material for the lateral leakage prevention sheet 10 may be processed after papermaking. Examples of the above-mentioned processes include embossing, creping, calendaring, water-repellent, plying, printing, etc.

When paper is used as the material for the lateral leakage prevention sheet 10, the basis weight may be 30 to 50 g/m ^2. The thickness of the paper may be 30 to 70 μm.

The side leakage prevention sheet 10 may be a laminated sheet formed by laminating multiple sheets of different materials. In that case, it is preferable that at least one of the sheets has a bending resistance of 100 mm or more, and at least one of the sheets may be paper. For example, the side leakage prevention sheet 10 may be a laminated sheet formed by laminating a core sheet having a bending resistance of 100 mm or more and a covering sheet having different properties from the core sheet, which covers the core sheet. Alternatively, the side leakage prevention sheet 10 may be a laminated sheet formed by laminating three sheets, and the laminated sheet may have a core sheet having a bending resistance of 100 mm or more arranged in the center and covering sheets having different properties from the core sheet arranged on both sides of the core sheet. For example, paper may be used as the core sheet, and a highly flexible nonwoven fabric may be used as the covering sheet. If the covering sheet is arranged on the top sheet side, the core sheet can be prevented from being exposed. This allows the side leakage prevention sheet 10 to maintain its side leakage prevention function while adding the property of being pleasant to the touch to the side leakage prevention sheet 10.

In the embodiment shown in FIG. 1, the width of the upper layer 13 and the width of the lower layer 14 of the side leakage prevention sheet 10 are the same, but they may be different. The width w of the upper layer 13 may be constant in the front-rear direction D1, or may vary depending on the position in the front-rear direction D1. For example, the width w may be different between the front joint portion 11f and the rear joint portion 11r of the side leakage prevention sheet 10 and the non-joint portion 12. The width w of the upper layer 13 (the average width when the width w varies depending on the position in the front-rear direction D1) is preferably 10 to 25 mm at least in the non-joint portion 12. By setting the width as described above, it is possible to ensure sufficient side leakage prevention function and prevent the area of the upper layer 13 in contact with the skin from becoming excessively large, causing discomfort.

(Modification)
Fig. 4 shows a plan view of a modified absorbent article 1A as viewed from the top sheet 3 side. The basic configuration of the absorbent article 1A is the same as that of the absorbent article 1 (Figs. 1 to 3), and is also the same as that of the side leakage prevention sheet 10. However, the absorbent article 1A differs from the absorbent article 1 (Figs. 1 to 3) in that the side leakage prevention sheet 10 of the absorbent article 1A is not flat, and at least the upper layer 13 has irregularities formed thereon. More specifically, the side leakage prevention sheet 10 of the absorbent article 1A has a plurality of recesses 21 formed at least in the upper layer 13. The plurality of recesses 21 may be formed over the entire upper layer 13 as shown in Fig. 4. In the side leakage prevention sheet 10, irregularities may also be formed in the lower layer 14.

Figure 5 shows a partially enlarged view of the cross section taken along line III-III in Figure 4. In the example shown in Figure 5, both the upper layer 13 and the lower layer 14 have concaves and convexes. More specifically, the upper layer 13 has concaves 21 recessed from the top sheet 3 side to the back sheet 2 side, and the lower layer 14 has convex parts 22 protruding from the back sheet 2 side to the top sheet 3 side. Such a side leakage prevention sheet 10 can be formed by forming a single sheet having multiple concaves or convex parts, and folding it back at the fold lines 15 so that the upper layer 13 has concaves 21 recessed from the top sheet 3 side to the back sheet 2 side.

By forming the recesses 21 in the upper layer 13, bodily fluids that have flowed outward in the lateral direction D2 can be captured in the recesses 21 when they reach the surface of the lateral leakage prevention sheet 10. This makes it possible to prevent bodily fluids migrating outward in the width direction D2 in the recesses 21, or to slow down the speed at which the bodily fluids migrate. When the recesses 21 are formed by the above-mentioned embossing process, the recesses 21 are formed by squeezing in the thickness direction, so that the density of the recesses 21 is high, and liquids tend to collect in the recesses 21 due to capillary action. This makes it possible to improve the bodily fluid capture effect.

The depth of the recess 21, i.e., the length d (Figure 5) in the thickness direction from the edge of the recess 21 to the bottom of the recess 21, is preferably 0.5 to 3 mm.

In addition, when the upper layer 13 has an upper layer concave portion 21 recessed from the top sheet 3 side toward the back sheet 2 side, and the lower layer 14 has a lower layer convex portion 22 protruding from the back sheet 2 side toward the top sheet 3 side, the upper layer concave portion 21 and the lower layer convex portion 22 may overlap in a planar view (Fig. 5). In that case, a space is likely to be formed between the upper layer 13 and the lower layer 14, and the upper layer 13 and the lower layer 14 are likely to separate. Therefore, the upper layer 13 is likely to be lifted in the direction shown by the arrow in Fig. 3, and the side leakage prevention function of the side leakage prevention sheet 10 can be improved.

In the example of FIG. 4, the upper layer recess 21 of the upper layer 13 has an elliptical shape in plan view, but the plan view shape of the upper layer recess 21 is not limited to that shown. The plan view shape of the upper layer recess 21 may be, for example, a circle, a triangle, a rectangle, etc., as shown in FIGS. 6(a) to (c). In addition to those shown in FIG. 6, the upper layer recess 21 may have other shapes such as a polygon other than a rectangle or triangle, a star, a heart, a teardrop, etc. In addition, the multiple recesses 21 may be arranged in a staggered pattern as shown in FIGS. 4 and 6(b), or may be arranged in a lattice pattern as shown in FIGS. 6(a) and (c).

The area of one recess 21 is preferably 1 to 25 ^mm2 , and more preferably 5 to 15 ^mm2 . The area ratio of the recesses 21, i.e., the ratio of the total area of the multiple recesses 21 to the entire area of the upper layer 13 in the region where the recesses 21 are provided, is preferably 20 to 60%. However, when there is a range in the front-rear direction D1 in the lateral leakage prevention sheet 10 where the recesses 21 are not provided, the area of the upper layer 13 used in calculating the above area ratio excludes such a range where the recesses 21 are not provided.

The shape, arrangement, and area of each recess 21 may be uniform throughout the upper layer 13, or may vary depending on the location. For example, recesses of different shapes in plan view may be combined, or recesses of different areas may be combined.

The planar shape of the lower layer convex portion 22 of the lower layer 14 that protrudes from the back sheet 2 side to the top sheet 3 side may be the same as the shape of the upper layer concave portion 21 described above. In addition, the area of one lower layer convex portion 22, as well as the arrangement and area ratio of the lower layer convex portions 22, may also be the same as the upper layer concave portion 21 described above.

The unevenness (recesses 21 and protrusions 22) formed on the lateral leakage prevention sheet 10 can be formed by embossing using a pair of rolls, a press machine, or the like. For example, the unevenness can be formed by passing a sheet between a roll having a convex or concave surface corresponding to the portion where the recess or protrusion is to be formed, and a flat roll with no unevenness on the surface. Alternatively, the unevenness can be formed by passing a sheet between a roll having a convex or concave surface corresponding to the portion where the recess or protrusion is to be formed, and a roll having a surface shape that is the inverse of the unevenness of the roll. Then, by folding back the sheet at a predetermined position after forming the unevenness on the sheet, the lateral leakage prevention sheet 10 in which the upper layer 13 has the recesses 21 and the lower layer 14 has the protrusions 22 can be obtained. By folding back the sheet after forming the unevenness in this way, it is not necessary to form the recesses 21 on the upper layer 13 and the protrusions 22 on the lower layer 14 in separate steps.

In the absorbent article 1A, the side leakage prevention sheet 10 can be configured as a laminated sheet formed by stacking multiple sheets with different characteristics. FIG. 7 shows an enlarged cross-sectional view of the side leakage prevention sheet 10, cut in the width direction D2, configured as a laminated sheet formed by stacking three sheets, in which a recess 21 is formed in the upper layer 13 and a protrusion 22 is formed in the lower layer 14. The side leakage prevention sheet 10 shown in FIG. 7 is a laminated sheet in which a first covering sheet 131 and a second covering sheet 132 are arranged on both sides of a core sheet 130. In the example shown in FIG. 7, the recess 21 of the upper layer 13 and the protrusion 22 of the lower layer 14 overlap in a plan view, as in the case of a single-layer sheet (FIG. 5). Therefore, in this example, the upper layer 13 is also easily lifted away from the lower layer 14.

Figure 8 shows a plan view of another modified absorbent article 1B as seen from the top sheet 3 side. The basic configuration of the absorbent article 1B is the same as that of the absorbent article 1 (Figures 1 to 3) and the absorbent article 1A (Figure 4), and the basic configuration of the side leakage prevention sheet 10 of the absorbent article 1B shown in Figure 8 is the same as that of the side leakage prevention sheet 10 of the absorbent article 1A (Figure 4). The side leakage prevention sheet 10 of the absorbent article 1B shown in Figure 8 also has unevenness formed at least in the upper layer 13. However, in the absorbent article 1B, the recess 21 formed in the upper layer 13 is formed only in the non-jointed portion 12. That is, in the absorbent article 1B shown in Figure 8, the recess 21 is not formed in the upper layer 13 at the front joint portion 11f and the rear joint portion 11r. This increases the area of contact between the upper layer 13 and the lower layer 14, and increases the adhesive strength between the upper layer 13 and the lower layer 14 at the front joint 11f and the rear joint 11r, so that the upper layer 13 can be reliably fixed in place before and after the non-jointed portion 12. This allows the upper layer 13 to rise at an appropriate angle so that it can make surface contact with the wearer's skin, more reliably forming a robust side leakage prevention means that is less likely to be crushed.

Furthermore, it is preferable that the lower layer 14 of the lateral leakage prevention sheet 10 does not have a protrusion 22 at the front joint 11f and the rear joint 11r. This increases the contact area between the upper layer 13 and the lower layer 14 and increases the adhesive strength between the two layers, thereby improving the effect of forming the robust lateral leakage prevention means described above.

1 Absorbent article 2 Back sheet 3 Top sheet 4 Absorbent body 10 Side leakage prevention sheet 11f Front joint portion 11r Rear joint portion 12 Non-joint portion 13 Upper layer 13a Outer end of upper layer 130 Core sheet 131 First covering sheet 132 Second covering sheet 14 Lower layer 15 Fold line 21 Upper layer recess 22 Lower layer protrusion AD Adhesive CL Front-rear center line D1 First direction D2 Second direction Q Region facing bodily fluid discharge port WG Wing w Width of side leakage prevention sheet

Claims (6)

An absorbent article having an elongated main body having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body provided between the top sheet and the back sheet,
A non-elastic side leakage prevention sheet is provided on the top sheet side of each end of the width direction of the main body, the non-elastic side leakage prevention sheet being arranged along the front-rear direction perpendicular to the width direction,
The side leakage prevention sheet is folded back at a fold line on the inside in the width direction to form an upper layer and a lower layer, and has a front joint portion where the upper layer and the lower layer are joined at the front, a rear joint portion where the upper layer and the lower layer are joined at the rear, and a non-joint portion between the front joint portion and the rear joint portion where the upper layer is not joined to the lower layer over the entire width direction of the upper layer ,
The lower layer is joined and fixed to the main body in the front-to-rear direction,
An absorbent article , wherein the upper layer at the non-jointed portion is capable of being lifted away from the lower layer using the fold line as a base point . The absorbent article according to claim 1, wherein the bending resistance of the side leakage prevention sheet is 100 mm or more. The absorbent article according to claim 1 or 2, wherein the side leakage prevention sheet comprises paper. The side leakage prevention sheet is a laminated sheet formed by laminating a plurality of sheets,
4. The absorbent article according to claim 2, wherein the laminated sheet comprises a core sheet having a bending resistance of 100 mm or more, and a covering sheet that covers the core sheet. The absorbent article according to any one of claims 1 to 4, wherein the upper layer has a plurality of upper layer recesses recessed from the top sheet side to the back sheet side. The absorbent article according to claim 5, wherein the lower layer has a plurality of lower layer convex portions formed thereon that protrude from the back sheet side to the top sheet side, and the upper layer concave portions and the lower layer convex portions overlap each other.

Images