Absorbent article

Abstract

To provide an absorbent article which is excellent in fitness and is equipped with an absorbent core that is hardly broken in use.SOLUTION: An absorbent core 5 which an absorbent article 1 is provided with has, at least in a crotch part C, openings 6 which pass through the absorbent core 5 in a thickness direction and extend in a lengthwise direction X. In each of the openings 6, there exist: a contact area 8 between a skin side sheet 7A in contact with a skin non-facing surface of the absorbent core 5 and a non-skin side sheet 7B in contact with a non-skin facing surface of the absorbent core 5 and a non-contact area 9 where both of the sheets 7A, 7B do not contact with each other. The non-contact area 9 includes a front non-contact area 9A located on a longitudinal front end 6a side of the opening 6 and a rear non-contact area 9B located on a longitudinal rear end 6b side of the opening 6. The front side non-contact area 9A is smaller than the rear side non-contact area 9B.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an absorbent article having an absorbent core that absorbs and retains body fluids such as urine. [Background technology]

[0002] In absorbent articles such as disposable diapers, an opening penetrating the absorbent core in the thickness direction may be provided in the absorbent core for the purpose of improving the fit to the wearer's body and improving leakproofness by controlling liquid permeability or liquid diffusibility. For example, Patent Documents 1 and 2 describe that the absorbent core of the absorbent article has a plurality of openings (non-stacking portions in Patent Document 1, channels in Patent Document 2) extending in the vertical direction (the direction corresponding to the front and rear direction of the wearer) intermittently arranged in the horizontal direction (the direction perpendicular to the vertical direction). On the other hand, when such openings are provided in the absorbent core, the shape retention of the absorbent core in a wet state decreases, and when the absorbent material (water-absorbent fiber, water-absorbent polymer, etc.) constituting the absorbent core absorbs body fluid and swells, the absorbent core breaks and loses its shape mainly around the opening, and the absorbent core is divided into multiple regions by the openings, which may cause inconveniences. Therefore, in the absorbent articles described in Patent Documents 1 and 2, two sheets arranged on either side of the absorbent core in the thickness direction are joined together at an opening provided in the absorbent core, thereby improving the shape retention of the absorbent core in a wet state and preventing breakage of the absorbent core due to the opening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-112404 A [Patent Document 2] Special Publication No. 2014-515981 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, in order to prevent breakage of the absorbent core due to openings, it is effective to join two sheets arranged on both sides of the absorbent core in the thickness direction at the openings, but as a result of various studies by the present inventors, it was found that the fit of the absorbent core to the body of a wearer of an absorbent article decreases depending on the joining method of the two sheets at the openings. No technology has yet been provided that achieves both fit and breakage prevention in an absorbent core with openings.

[0005] An object of the present invention is to provide an absorbent article having an absorbent core that has excellent fit and is not easily broken during use. [Means for solving the problem]

[0006] The present invention provides a garment having a vertical direction corresponding to the front-to-back direction of a wearer and a horizontal direction perpendicular thereto, and also having a ventral side portion disposed on the ventral side of the wearer when worn, a dorsal side portion disposed on the dorsal side of the wearer, and a crotch portion disposed between the ventral side portion and the dorsal side portion, This absorbent article comprises an absorbent core that absorbs and retains bodily fluids, and a longitudinally stretchable portion that extends in the longitudinal direction along the absorbent core and has a portion that is positioned along the wearer's legs when worn. In one embodiment of the absorbent article of the present invention, the absorbent core has an opening, at least in the crotch portion, penetrating the absorbent core in a thickness direction and extending in the longitudinal direction. In one embodiment of the absorbent article of the present invention, the opening has a bonded area between the skin-side sheet that contacts the skin-facing surface of the absorbent core and the non-skin-side sheet that contacts the non-skin-facing surface of the absorbent core, and a non-bonded area where the two sheets are not bonded to each other. In one embodiment of the absorbent article of the present invention, the non-bonded region includes a front non-bonded region located on the longitudinal front end side of the opening, and a rear non-bonded region located on the longitudinal rear end side of the opening. In one embodiment of the absorbent article of the present invention, the front non-bonded region has an area smaller than that of the rear non-bonded region. Other features, advantages and embodiments of the present invention are described below. Effect of the Invention

[0007] According to the present invention, an absorbent article is provided that has an absorbent core that has excellent fit and is not easily broken during use. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a developed plan view of the skin-facing surface side of a pants-type disposable diaper, which is one embodiment of the absorbent article of the present invention, in an unfolded and maximally stretched state. [Diagram 2] FIG. 2 is a cross-sectional view of the diaper shown in FIG. 1 taken along line II. [Diagram 3] FIG. 3 is a cross-sectional view of the diaper shown in FIG. 1 taken along line II-II. [Figure 4] FIG. 4 is a diagram showing a schematic view of the absorbent core when the diaper shown in FIG. 1 is worn, and is a cross-sectional view taken along the longitudinal direction of a region that is located at the same longitudinal position as the opening in the absorbent core. [Diagram 5] FIG. 5 is a developed plan view of the skin-facing side of a pants-type disposable diaper, which is another embodiment of the absorbent article of the present invention, in the developed and maximally stretched state. [Figure 6] 6 is a cross-sectional view of the diaper shown in FIG. 5 taken along line III-III. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below based on preferred embodiments with reference to the drawings. Note that common reference numerals are used to designate the same parts in the drawings. The drawings are basically schematic, and the dimensions and dimensional ratios of certain parts to other parts may differ from the actual ones.

[0010] 1 to 3 show a pants-type disposable diaper 1, which is one embodiment of the absorbent article of the present invention. The diaper 1 has a longitudinal direction X corresponding to the front-to-rear direction of a wearer and a transverse direction Y perpendicular thereto, and also has a ventral side portion A arranged on the ventral side of the wearer when worn, a dorsal side portion B arranged on the dorsal side of the wearer, and a crotch portion C located between the ventral side portion A and the dorsal side portion B. The longitudinal direction X is a direction extending from the ventral side portion A through the crotch portion C to the dorsal side portion B. The diaper 1 also comprises an absorbent core 5 that absorbs and retains bodily fluids, and longitudinally stretchable portions, namely, leakproof cuffs 10 (first longitudinally stretchable portions) and leg cuffs 13 (second longitudinally stretchable portions), which extend in the longitudinal direction X along the absorbent core 5 and have portions that are positioned around the legs of the wearer when worn.

[0011] The crotch portion C extends in the longitudinal direction X across a longitudinal centerline CLx of the diaper 1. The longitudinal centerline CLx is an imaginary straight line extending in the transverse direction Y, dividing the diaper 1 in the fully stretched and unfolded state as shown in FIG. The crotch portion C includes an excretory part facing portion (not shown) that faces the wearer's excretory part such as the penis, and typically includes a portion of the diaper 1 whose length (width) in the lateral direction Y is the shortest. In the present invention, the abdominal portion A, the crotch portion C and the back portion B may be each of the regions obtained by dividing the absorbent article in an unfolded and maximally stretched state into three equal parts in the longitudinal direction X.

[0012] In this specification, the term "unfolded and maximally stretched state" refers to a state in which the absorbent article is spread out flat to an unfolded state, and the elastic members of each part of the absorbent article in the unfolded state are stretched to their maximum extent until the absorbent article is expanded to the same dimensions as the design dimensions, i.e., the dimensions when the absorbent article is unfolded flat in a state in which the influence of the elastic members is completely eliminated. In the case of an absorbent article having side seals, the absorbent article is cut at the side seals and spread out flat to the unfolded state.

[0013] In this embodiment, the diaper 1 is formed symmetrically on one side and the other side with respect to a lateral centerline CLy in the unfolded and maximally stretched state as shown in Fig. 1. The lateral centerline CLy is an imaginary straight line extending in the longitudinal direction X and dividing the diaper 1 in the unfolded and maximally stretched state into two equal parts in the lateral direction Y. The diaper 1 comprises an absorbent body 2 including an absorbent core 5, and an exterior body 20 disposed on the non-skin-facing side of the absorbent body 2. The absorbent body 2 and the exterior body 20 are joined together by a known joining means such as an adhesive.

[0014] In this specification, the "skin-facing side" refers to the side of the absorbent article or its constituent members (e.g., absorbent core) that faces the wearer's skin when the absorbent article is worn, i.e., the side relatively close to the wearer's skin, and the "non-skin-facing side" refers to the side of the absorbent article or its constituent members that faces the opposite side to the skin when the absorbent article is worn, i.e., the side relatively far from the wearer's skin. Note that "when worn" here refers to the normal, proper wearing position, i.e., a state in which the absorbent article is maintained in the correct wearing position.

[0015] In this embodiment, the exterior body 20 includes a ventral exterior body 20A constituting the ventral portion A and a rear exterior body 20B constituting the rear portion B. Both exterior bodies 20A, 20B are independent members and are arranged at a predetermined interval in the vertical direction X. On the other hand, the absorbent body 2 has a rectangular shape in a plan view and is bridged between both exterior bodies 20A, 20B with its longitudinal direction aligned with the vertical direction X of the diaper 1. The diaper 1 is thus a so-called split-type pants-type disposable diaper in which the exterior body 20 is divided into a member 20A arranged on the ventral side and a member 20B arranged on the rear side. Although not shown, when the diaper 1 is worn, the ventral exterior body 20A and the rear exterior body 20B are connected at both side portions S, S along the vertical direction X, and the exterior body 20 is annular. The diaper 1 including this annular exterior body 20 has a waist opening through which the wearer's torso passes, and a pair of leg openings through which the wearer's lower legs pass.

[0016] Each of the exterior bodies 20A and 20B includes an outer layer sheet (not shown) forming the outer surface of the diaper 1, an inner layer sheet 21 forming the inner surface of the diaper 1, and a waist-line elastic member 22 interposed between the two sheets. The waist-line elastic member 22 extends in the horizontal direction Y and is intermittently arranged in the vertical direction X. Each of the exterior bodies 20A and 20B is produced by fixing the waist-line elastic member 22 between the outer layer sheet and the inner layer sheet 21 in a state in which the waist-line elastic member 22 is stretched in the horizontal direction Y, and then releasing the waist-line elastic member 22 from the stretched state, thereby providing stretchability in the horizontal direction Y. As the outer layer sheet and the inner layer sheet 21, any sheet used as an exterior body in this type of absorbent article can be used without any particular limitation, and for example, nonwoven fabrics produced by various methods can be used.

[0017] The absorbent body 2 is composed of a liquid-permeable top sheet 3 arranged relatively close to the wearer's skin, a liquid-impermeable or poorly liquid-permeable or water-repellent back sheet 4 arranged relatively far from the wearer's skin, an absorbent core 5 interposed between the two sheets 3, 4, and a core wrap sheet 7 covering the absorbent core 5. These components constituting the absorbent body 2 are integrated together by known joining means such as adhesives. The component consisting of the absorbent core 5 and the core wrap sheets 7 (7A, 7B) is also called the "absorbent body."

[0018] The top sheet 3, the back sheet 4, and the core wrap sheet 7 may be any sheet that is commonly used in this type of absorbent article, without any particular restrictions. The top sheet 3 and the core wrap sheet 7 may be any liquid-permeable sheet, such as nonwoven fabric, woven fabric, or paper. The back sheet 4 may be a leak-proof sheet, specifically a liquid-impermeable sheet (no liquid permeable property) or a liquid-difficult-to-permeable sheet (not liquid-impermeable, but difficult to pass liquid through), such as a moisture-permeable resin film or a laminate of the resin film and a nonwoven fabric.

[0019] The core wrap sheet 7 includes a skin side sheet 7A that contacts the skin facing surface of the absorbent core 5, and a non-skin side sheet 7B that contacts the non-skin facing surface of the absorbent core 5. In this embodiment, the core wrap sheet 7 is a single sheet, and the skin side sheet 7A and the non-skin side sheet 7B are each part of the single sheet, but in the present invention, the form of the core wrap sheet is not limited to this, and the skin side sheet 7A and the non-skin side sheet 7B may be separate sheets. In other words, the core wrap sheet 7 may be composed of multiple sheets 7A, 7B.

[0020] In this embodiment, as shown in Fig. 1, a pair of leakage preventing cuffs 10 (first longitudinally stretchable portions) are arranged on both sides of the absorbent core 5 in the lateral direction Y on the skin-facing side of the diaper 1. The leakage preventing cuffs 10 include a side sheet 11 which forms the main part of the leakage preventing cuffs 10, and a leakage preventing cuff-forming elastic member 12 which is fixed to the side sheet 11 and is stretchable in the longitudinal direction X. The side sheet 11, together with the top sheet 3, forms the skin-facing surface of the diaper 1 and extends in the longitudinal direction X of the absorbent body 2 over substantially the entire length of the absorbent body 2. The side sheet 11 has, on the skin-facing side of the diaper 1, an outer edge located on the outer side in the lateral direction Y (relatively farther from the lateral centerline CLy) and an inner edge located on the inner side in the lateral direction Y (relatively closer to the lateral centerline CLy), the outer edge being fixed to another member (the back sheet 4 in this embodiment), and the inner edge being a free edge not fixed to another member. In addition, a portion of the side sheet 11 adjacent to the outer edge in the lateral direction Y and located on the opposite side to the inner edge is folded back to the non-skin-facing side of the back sheet 4 and is fixed between the back sheet 4 and an outer layer nonwoven fabric 40 arranged on the non-skin-facing side thereof, as shown in Figs. 2 and 3. In addition, both ends of the side sheet 11 in the longitudinal direction X are fixed to other members (the top sheet 3 and the back sheet 4 in this embodiment) over the entire length in the transverse direction Y. In other words, the parts of the side sheet 11 other than the inner edge are fixed to other members. Meanwhile, the elastic member 12 is disposed on the inner edge (free edge) of the side sheet 11. More specifically, the inner edge of the side sheet 11 is made of a two-layer structure of the side sheet 11 that is formed by folding the side sheet 11, and the elastic member 12 extending in the longitudinal direction X is fixed in a stretched state between the opposing side sheets 11, 11 that constitute the two-layer structure. The portions of the leakproof cuffs 10 where the elastic members 12 are fixed in a stretched state are the stretchable regions of the leakproof cuffs 10, i.e., the first longitudinally stretchable portions. In this embodiment, the portions where the elastic members 12 are present, as shown by dotted lines in Fig. 1, are the stretchable regions of the leakproof cuffs 10 (first longitudinally stretchable portions), which extend over the entire length of the crotch portion C in the longitudinal direction X and further into the abdominal portion A and the dorsal portion B. When the diaper 1 is worn or in its natural state (when no external force is acting), the stretchable regions of the leakproof cuffs 10 rise up toward the wearer's skin, thereby effectively preventing excreted body fluids, such as urine, from leaking outward in the lateral direction Y from the diaper 1 (so-called lateral leakage). As the side sheet 11, any material used as a leakproof cuff in this type of absorbent article can be used without any particular limitation, such as a single-layer or multi-layer water-repellent nonwoven fabric, a laminate of a resin film and a nonwoven fabric, etc. Furthermore, the number of leakproof cuff-forming elastic members 12 arranged in the leakproof cuff 10 is not particularly limited, and may be one, or may be three or more.

[0021] 1, a pair of leg cuffs 13 (second longitudinally stretchable portions) are disposed on both sides of the absorbent core 5 in the lateral direction Y and further outward in the lateral direction Y than the leakage preventing cuffs 10. The leg cuffs 13 are disposed in the portions of the diaper 1 that correspond to the legs of the wearer (leg portions), and include a leg cuff-forming sheet and leg cuff-forming elastic members 14 that are fixed to the sheet and can stretch along the legs of the wearer. In this embodiment, the leg edge forming sheets are the back sheet 4 and the side sheet 11, as shown in Figures 2 and 3. The elastic member 14 is fixed between the sheets 4 and 11 in a stretched state in the longitudinal direction X, and is arranged to be stretchable in the longitudinal direction X. The portion of the leg cuff 13 where the elastic members 14 are fixed in a stretched state is the stretchable region of the leg cuff 13, i.e., the second longitudinally stretchable portion. In this embodiment, the portion where the elastic members 14 are present, as shown by dotted lines in Fig. 1, is the stretchable region of the leg cuff 13 (second longitudinally stretchable portion), which extends over the entire length of the crotch portion C in the longitudinal direction X and further into the abdominal portion A and the dorsal portion B. When the diaper 1 is worn or in its natural state, contraction of the elastic members 14 forms leg gathers (wrinkles) in the leg edge forming sheet, which are continuous in the extension direction of the elastic members 14. In this embodiment, the stretchable area of ​​the leg cuff 13 (second vertically stretchable portion) is located at the same position in the vertical direction X as the stretchable area of ​​the leakage preventing cuff 10 (first vertically stretchable portion), i.e., the projection image of the former in the horizontal direction Y coincides with that of the latter.

[0022] The absorbent core 5, which is one of the main characteristic parts of the diaper 1, will now be described. The absorbent core 5 is mainly composed of a water-absorbing material. Examples of the water-absorbing material include hydrophilic fibers and water-absorbing polymers, and these can be used alone or in combination of two or more. Examples of the hydrophilic fibers include natural fibers such as wood pulp, and hydrophilic synthetic fibers. Examples of the water-absorbing polymers include those that have been conventionally used in this type of absorbent without any particular restrictions, and examples of such polymers include polymers or copolymers of acrylic acid or alkali metal salts of acrylic acid.

[0023] 1, the absorbent core 5 has a shape that is long in one direction (specifically, a rectangular shape) in a plan view, and extends from the abdominal portion A through the crotch portion C to the back portion B with its longitudinal direction coinciding with the longitudinal direction X of the diaper 1. Since the crotch portion C is a region where bodily fluids excreted from the wearer's excretory area are concentrated, it is preferable that the absorbent core 5 having the ability to absorb and retain bodily fluids is disposed at least in the crotch portion C.

[0024] The absorbent core 5 has an opening 6 at least in the crotch portion C, which penetrates the absorbent core 5 in the thickness direction and extends in the longitudinal direction X. The opening 6 is a through-hole having a long shape in the longitudinal direction X in a plan view of the diaper 1 as shown in Fig. 1, and has openings on both the skin-facing surface and the non-skin-facing surface of the absorbent core 5. The opening 6 is a space in which the material forming the absorbent core 5 is substantially absent.

[0025] In this embodiment, as shown in Fig. 1, a pair of openings 6 are arranged on one side and the other side of a horizontal centerline CLy, which is an imaginary straight line extending in the vertical direction while dividing the diaper 1 in half in the horizontal direction Y. Each of the pair of openings 6, 6 has a rectangular shape that is long in the vertical direction X in a plan view of the absorbent core 5 as shown in Fig. 1, and extends over the entire length of the crotch portion C in the vertical direction X and further into the abdominal portion A and the dorsal portion B.

[0026] The openings 6 can be formed by not depositing the forming material (water-absorbent material) of the absorbent core 5 in the area where the openings 6 are to be formed during the manufacturing process of the absorbent core 5. Another method for forming the openings 6 includes a method in which a precursor of the absorbent core 5 having a uniform amount of deposited forming material is manufactured, and the forming material is removed from the area where the openings 6 are to be formed in the precursor. The central opening 6C can also be formed in the same manner as the openings 6.

[0027] As shown in FIG. 1, the opening 6 has a bonded region 8 between the skin-side sheet 7A that contacts the skin-facing surface of the absorbent core 5 and the non-skin-side sheet 7B that contacts the non-skin-facing surface of the absorbent core 5, and a non-bonded region 9 where the two sheets 7A, 7B are not bonded to each other. The non-bonded region 9 includes a front non-bonded region 9A located on the front end 6a side of the opening 6 in the longitudinal direction, and a rear non-bonded region 9B located on the rear end 6b side of the opening 6 in the longitudinal direction. The longitudinal front end 6a of the opening 6 refers to the end of the opening 6 in the longitudinal direction X that is closer to the ventral part A, and the longitudinal rear end 6b of the opening 6 refers to the end of the opening 6 in the longitudinal direction X that is closer to the dorsal part B. The front non-bonded region 9A is a continuous region extending from the longitudinal front end 6a of the opening 6 to a position spaced a predetermined distance inward in the longitudinal direction X, and the rear non-bonded region 9B is a continuous region extending from the longitudinal rear end 6b of the opening 6 to a position spaced a predetermined distance inward in the longitudinal direction X.

[0028] In the bonding region 8, the means for bonding the skin side sheet 7A and the non-skin side sheet 7B is not particularly limited, and may be, for example, an adhesive, fusion, or a combination of two or more bonding means. When bonding the sheets 7A and 7B by fusion, the sheets 7A and 7B may be fused by heating, or may be fused by applying ultrasonic waves to the sheets 7A and 7B.

[0029] The bonding area 8 may be in a form in which the entire area is a bonding portion of both sheets 7A, 7B (hereinafter also referred to as "first form"), or in a form including a non-bonded portion of both sheets 7A, 7B (hereinafter also referred to as "second form"). For example, when an adhesive is used as a means for bonding both sheets 7A, 7B, if the adhesive is applied (so-called solid application) to the entire area where the bonding area 8 is to be formed, the bonding area 8 of the first form is obtained, and if the adhesive is applied intermittently to the area where the bonding area 8 is to be formed, the bonding area 8 of the second form is obtained. The boundary between the joint region 8 and the front non-joined region 9A in the second form is the outer end in the longitudinal direction X of the joint between the sheets 7A, 7B that is closest to the longitudinal front end 6a of the opening 6 (the end in the longitudinal direction X closer to the longitudinal front end 6a). The boundary between the joint region 8 and the rear non-joined region 9B in the second form is the outer end in the longitudinal direction X of the joint between the sheets 7A, 7B that is closest to the longitudinal rear end 6b of the opening 6 (the end in the longitudinal direction X closer to the longitudinal rear end 6b).

[0030] 1, the central opening 6C also has a bonded region 8 and a non-bonded region 9 (a front non-bonded region 9A and a rear non-bonded region 9B). Like the opening 6, the central opening 6C also has a longitudinal front end 6a and a longitudinal rear end 6b. Unless otherwise specified, the same description of the opening 6 applies to the central opening 6C as appropriate.

[0031] One of the main features of the absorbent article of the present invention, typified by the diaper 1, is that the front non-bonded region 9A has a smaller area than the rear non-bonded region 9B. As described above, by forming the opening 6 in the absorbent core 5, the flexibility (ease of deformation) of the absorbent core 5 is improved, and the fit of the absorbent core 5 can be improved, but the shape retention of the absorbent core 5 in a wet state is reduced, and the absorbent core 5 becomes more likely to break after absorbing body fluids. This problem of breakage of the absorbent core 5 can be prevented by bonding two sheets 7A and 7B arranged on both sides of the absorbent core 5 in the thickness direction at the opening 6, and in this embodiment, the bonding region 8 plays this role. However, the inventor's study has revealed that there is a problem to be improved in the bonding portion between sheets at the opening of the absorbent core, such as the bonding region 8. That is, the bonding region 8 is mainly composed of the part where the two sheets 7A and 7B are bonded by adhesive or fusion, and therefore has higher rigidity than other regions in the absorbent core 5, such as the non-bonded region 9. Therefore, if the ratio of the area of ​​the bonding region 8 to the total area of ​​the opening 6 (area ratio of the bonding region) is high, the rigidity of the absorbent core 5 is increased, and the fit of the absorbent core 5 is reduced. For example, if the entire opening 6 is a bonding region 8, it will be difficult for the front longitudinal end 6a and the rear longitudinal end 6b of the opening 6 to conform to the wearer's body, and the fit of the portions that are a certain distance away in the longitudinal direction X from the longitudinal center line CLx of the diaper 1, such as the front longitudinal end 6a and the rear longitudinal end 6b, will be reduced. In contrast, in the diaper 1, the entire opening 6 is not made into a bonded region 8, but the side of the longitudinal front end 6a of the opening 6 is made into a front non-bonded region 9A, and the side of the longitudinal rear end 6b of the opening 6 is made into a rear non-bonded region 9B, and the areas of the non-bonded regions 9A, 9B are set to satisfy the above-mentioned relationship "area of ​​the front non-bonded region 9A < area of ​​the rear non-bonded region 9B", so that the portion of the absorbent core 5 extending from the longitudinal front end 6a to the longitudinal rear end 6b of the opening 6 and the portion at the same position in the longitudinal direction X can closely fit the body of the wearer 100, as shown in Fig. 4. In this way, the diaper 1 makes use of the merit of the bonded region 8 (prevention of breakage of the absorbent core 5 while the diaper 1 is being worn) while reducing the demerit of the bonded region 8 (reduction in the fit of the absorbent core 5), and is thus an absorbent article equipped with an absorbent core that is excellent in fit and does not easily break during use.

[0032] Thus, the establishment of the size relationship allows the absorbent core to improve its fit while preventing breakage at the same time, which is related to "longitudinal stretchable parts that extend longitudinally along the absorbent core and have parts that are arranged along the legs of the wearer when worn." That is, for example, in the diaper 1, the longitudinal stretchable parts include the leakage preventing cuffs 10 (first longitudinal stretchable parts) and the leg cuffs 13 (second longitudinal stretchable parts), and in order for the absorbent core 5 to deform into a boat-like shape concave toward the body of the wearer 100 as shown in Fig. 4 and to closely follow the body of the wearer 100, it is important that the elasticity of the leakage preventing cuffs 10 and the leg cuffs 13 arranged on both sides of the absorbent core 5 in the lateral direction Y is expressed when the diaper 1 is worn, and that the boat-like deformation of the absorbent core 5 is promoted. Here, if the entire opening 6 were the bonding region 8, the stretchability of the leakproof cuffs 10 and leg cuffs 13 would be hindered, which may make it difficult for the absorbent core 5 to deform into a boat shape. In contrast, in the diaper 1, the above-mentioned size relationship is established, so that the inhibition of the stretchability of the leakproof cuffs 10 and leg cuffs 13 by the bonding region 8 is reduced, and therefore, even though the diaper 1 has the bonding region 8, the absorbent core 5 deforms into a boat shape when worn, and the absorbent core 5 fits the wearer's body as shown in Figure 4.

[0033] In the present invention, when an absorbent core has a plurality of openings, the above-mentioned relationship "area of ​​front non-bonded region < area of ​​rear non-bonded region" preferably holds for all of the plurality of openings. The diaper 1 is a preferred embodiment, in which the above-mentioned relationship holds for each of a pair of openings 6, 6. In addition, unless otherwise specified, it is preferred that each of the plurality of openings in the absorbent core has the configurations of the opening 6, bonded region 8, and non-bonded region 9 described below.

[0034] In order to more reliably achieve the effect of the above-mentioned relationship "area of ​​the front non-bonded region 9A < area of ​​the rear non-bonded region 9B", when the diaper 1 is unfolded and fully extended as shown in Figure 1, the ratio of the area of ​​the front non-bonded region 9A to the area of ​​the rear non-bonded region 9B, (former / latter), is preferably 0.3 or more, more preferably 0.4 or more, and preferably 0.9 or less, more preferably 0.8 or less. The area of ​​the front non-bonded region 9A is preferably 75 mm 2 on the assumption that it is smaller than the area of ​​the rear non-bonded region 9B. 2 More than 80mm, preferably 80mm 2 More than 110mm, preferably 2 Less than or equal to 105mm, preferably 2 The following is the result. The area of ​​the rear non-bonded region 9B is preferably 115 mm 2 , provided that the area is larger than the area of ​​the front non-bonded region 9A. 2 More than 120mm, preferably 2 More than 175mm, preferably 2 Less than or equal to 170mm, more preferably 2 The following is the result.

[0035] The areas of the bonded region 8 and the non-bonded region 9 (9A, 9B) in the opening 6 can be measured by a standard method. Specifically, for example, a mold of the opening 6 is taken by pressing a piece of paper against the opening 6 and copying the shape of the opening 6 (the outline of the opening 6, the boundary between the bonded region 8 and the non-bonded region 9, etc.) onto the paper, and the area of ​​a desired region of the opening 6 (e.g., the non-bonded regions 9A, 9B) is calculated based on the mold taken.

[0036] In this embodiment, the vertical length of the opening 6 is longer than its horizontal length, as shown in Fig. 1. The "vertical length" here refers to the entire length of the opening 6 in the vertical direction X, and the "horizontal length" refers to the length (width) of the opening 6 in the horizontal direction Y. In this embodiment, the horizontal length of the opening 6 is constant over the entire length of the opening 6 in the vertical direction X, but when the horizontal length of the opening 6 varies partially, it is preferable that the vertical length of the opening 6 is longer than the maximum horizontal length (maximum width) of the opening 6. By satisfying the above-mentioned size relationship "vertical length of opening 6>horizontal length of opening 6", it is possible to improve the fit of the absorbent core 5 and prevent breakage at the same time, and the desired effect of the present invention (providing an absorbent article having an absorbent core that has excellent fit and is not easily broken during use) can be more reliably achieved. Furthermore, since the opening 6 functions as a flow path for bodily fluids such as urine excreted by the wearer of the diaper 1, an absorbent core 5 having a vertically long opening 6 that satisfies the above-mentioned size relationship has excellent liquid diffusibility in the vertical direction X and can be used entirely for liquid absorption, so that the diaper 1 having such an absorbent core 5 has excellent liquid absorbency. In order to more reliably obtain the effect of the above-mentioned relationship "vertical length of opening 6>horizontal length of opening 6", when diaper 1 is in an unfolded and maximally stretched state as shown in FIG. 1, the ratio of the vertical length of opening 6 to the horizontal length of opening 6, as the former / the latter, is preferably 5 or more, more preferably 7 or more, and is preferably 26 or less, more preferably 24 or less.

[0037] The lateral length of the opening 6 is not particularly limited, but from the viewpoint of preventing breakage of the absorbent core 5, it is preferably 20 mm or less, more preferably 15 mm or less, when the diaper 1 is in an unfolded and maximum stretched state as shown in Fig. 1. Moreover, from the viewpoint of improving the fit and liquid absorbency of the absorbent core 5, the lower limit of the lateral length of the opening 6 is preferably 5 mm or more, more preferably 10 mm or more, when the diaper 1 is in an unfolded and maximum stretched state. When the lateral length of the opening 6 varies partially, the "lateral length" referred to here refers to the maximum lateral length.

[0038] The vertical length of the opening 6 is not particularly limited, but from the viewpoint of preventing breakage of the absorbent core 5, it is preferably 2 / 3 or less, and more preferably 7 / 12 or less, of the vertical length (total length in the vertical direction X) of the absorbent core 5 when the diaper 1 is unfolded and maximally stretched as shown in Fig. 1. Moreover, from the viewpoint of improving the fit and liquid absorbency of the absorbent core 5, the lower limit of the vertical length of the opening 6 is preferably 1 / 4 or more, and more preferably 2 / 5 or more, of the vertical length (total length in the vertical direction X) of the absorbent core 5 when the diaper 1 is unfolded and maximally stretched.

[0039] The vertical length of the opening 6 is, on the premise that it is longer than the horizontal length of the opening 6 and is 2 / 3 or less of the vertical length of the absorbent core 5, preferably 80 mm or more, more preferably 100 mm or more, and preferably 250 mm or less, more preferably 240 mm or less, when the diaper 1 is in the unfolded and maximum extended state as shown in FIG. 1.

[0040] From the viewpoint of improving the fit of the absorbent core 5, the ratio of the area of ​​each of the front non-bonded region 9A and the rear non-bonded region 9B to the total area of ​​the opening 6 (area ratio of the non-bonded regions) is preferably 3% or more, and more preferably 4% or more, when the diaper 1 is unfolded and fully stretched as shown in Fig. 1. Moreover, from the viewpoint of preventing breakage of the absorbent core 5, the upper limit of the area ratio of the non-bonded regions is preferably 30% or less, and more preferably 26% or less, when the diaper 1 is unfolded and fully stretched.

[0041] From the viewpoint of improving the fit of the absorbent core 5, when the diaper 1 is in an unfolded and maximum stretched state as shown in Fig. 1, the longitudinal length of the bonded region 8 is preferably at least 1.5 times, and more preferably at least 1.8 times, the longitudinal length of the non-bonded region 9. The "longitudinal length of the non-bonded region 9" referred to here means the sum of the longitudinal lengths of the front non-bonded region 9A and the rear non-bonded region 9B. From the viewpoint of preventing breakage of the absorbent core 5, when the diaper 1 is in an unfolded and maximum stretched state, the longitudinal length of the bonded region 8 is preferably at most 3.2 times, and more preferably at most 3.0 times, the longitudinal length of the non-bonded region 9.

[0042] From the viewpoint of improving the fit of the absorbent core 5, in the unfolded and maximum stretched state of the diaper 1 as shown in Fig. 1, the longitudinal length from the longitudinal centerline CLx (a virtual straight line extending in the transverse direction Y by dividing the diaper 1 in half in the longitudinal direction X) to the longitudinal rear end of the joining region 8 (the boundary between the joining region 8 and the rear non-joined region 9B) (hereinafter also referred to as the "longitudinal rear length of the joining region") is preferably 80% or less, more preferably 78% or less, of the longitudinal length from the longitudinal centerline CLx to the longitudinal front end of the joining region 8 (the boundary between the joining region 8 and the front non-joined region 9A) (hereinafter also referred to as the "longitudinal front length of the joining region"). From the viewpoint of preventing breakage of the absorbent core 5, in the unfolded and maximum stretched state of the diaper 1, the longitudinal rear length of the joining region 8 is preferably 40% or more, more preferably 45% or more, of the longitudinal front length of the joining region 8.

[0043] From the viewpoint of improving the fit of the absorbent core 5, the longitudinal length of the overlapping portion in the longitudinal direction X between the opening 6 and the longitudinally stretchable portions (leakproof cuffs 10, leg cuffs 13) is preferably at least 50%, more preferably at least 55%, of the longitudinal length of the stretchable region of the longitudinally stretchable portion when the diaper 1 is unfolded and at its maximum stretched state as shown in Fig. 1. The "overlapping portion" refers to the overlapping portion between the projected images of the opening 6 and the longitudinally stretchable portions when they are projected in the lateral direction Y when the diaper 1 is unfolded and at its maximum stretched state. In this embodiment, there are two types of longitudinally stretchable parts, namely, the leakage preventing cuffs 10 and the leg cuffs 13. When an absorbent article has a plurality of types of longitudinally stretchable parts, it is preferable that the ratio of the longitudinal length of the overlapping part to the longitudinal length of the stretched region of each longitudinally stretchable part is 50% or more. This embodiment is such a preferable form, in which the ratio of the longitudinal length of the overlapping part to the length in the longitudinal direction X of the stretched region of the leakage preventing cuffs 10 (the region where the leakage preventing cuff-forming elastic member 12 is fixed in a stretched state) (the length of the dotted line showing the elastic member 12 in FIG. 1) is 50% or more, and the ratio of the longitudinal length of the overlapping part to the length in the longitudinal direction X of the stretched region of the leg cuffs 13 (the region where the leg cuff-forming elastic member 14 is fixed in a stretched state) (the length of the dotted line showing the elastic member 14 in FIG. 1) is 50% or more. In order to prevent tightness, when the diaper 1 is unfolded and fully stretched, the longitudinal length of the overlapping portion in the longitudinal direction X between the opening 6 and the longitudinally stretchable portion (leakproof cuffs 10, leg cuffs 13) is preferably 67% or less, and more preferably 65% ​​or less, of the longitudinal length of the stretchable region of the longitudinally stretchable portion.

[0044] 1, the non-bonded regions 9 (9A, 9B) overlap with the stretchable regions of the longitudinally stretchable parts (leakproof cuffs 10, leg cuffs 13) or are located inward of the stretchable regions in the longitudinal direction X and inward of the stretchable regions in the lateral direction Y. This, combined with the effect of achieving the relationship "area of ​​front non-bonded region 9A < area of ​​rear non-bonded region 9B", can further improve the fit of the absorbent core 5. In the embodiment shown in FIG. 1, the non-bonded regions 9 (9A, 9B) overlap with the stretchable regions of the leakage preventing cuffs 10 (regions where the leakage preventing cuff-forming elastic members 12 are fixed in a stretched state) and are located inward in the vertical direction X and inward in the horizontal direction Y of the stretchable regions of the leg cuffs 13 (regions where the leg cuff-forming elastic members 14 are fixed in a stretched state).

[0045] 1 to 3, the absorbent core 5 has a central opening 6C penetrating the absorbent core 5 in the thickness direction and extending in the longitudinal direction X at a position overlapping with the horizontal centerline CLy between the pair of openings 6, 6. In this way, the presence of the central opening 6C in the absorbent core 5 in addition to the pair of openings 6, 6, coupled with the effect of establishing the size relationship "area of ​​the front non-bonded region 9A<area of ​​the rear non-bonded region 9B", can further improve the fit of the absorbent core 5. In the illustrated embodiment, the central opening 6C has the same shape and dimensions as the opening 6 in a plan view and is located at the same position in the vertical direction X as each of the pair of openings 6, 6; however, the shape and dimensions of the central opening 6C in a plan view are not particularly limited and can be set arbitrarily. In the illustrated embodiment, the central opening 6C does not have a bonded region 8, and the two sheets 7A, 7B arranged on both sides of the absorbent core 5 in the thickness direction are not bonded to each other at the central opening 6C, but the sheets 7A, 7B may be bonded to each other at the central opening 6C. In that case, the central opening 6C may have a front non-bonded region 9A and a rear non-bonded region 9B, as in the opening 6, and further the above-mentioned relationship in size may be established between the areas of the bonded regions 9A, 9B.

[0046] 5 and 6 show a pants-type disposable diaper 1A which is another embodiment of the absorbent article of the present invention. In the embodiment described later, the configurations different from the diaper 1 described above will be mainly described, and the same configurations as those of the diaper 1 in the embodiment described later will be denoted by the same reference numerals and will not be described. For the configurations not specifically described in the embodiment described later, the description of the diaper 1 described above will be applied as appropriate.

[0047] In the diaper 1A, the opening 6 is disposed so as to overlap with the horizontal centerline CLy (an imaginary straight line that bisects the diaper 1 in the horizontal direction Y and extends in the vertical direction X). The absorbent core 5 of the diaper 1A has only one opening 6 that overlaps with the horizontal centerline CLy. The diaper 1A basically achieves the same effects as the diaper 1.

[0048] The present invention can be applied to absorbent articles in general. The term "absorbent article" as used herein broadly includes articles used to absorb body fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body, and includes, in addition to the pants-type disposable diaper of the above embodiment, for example, flat-type disposable diapers, sanitary shorts, incontinence pads, etc. The flat-type disposable diaper is a disposable diaper in which the abdominal side part and the back side part are not connected in an unused state, and the waist part placed around the wearer's waist is not annular, and typically has a fastening tape on the back side part, and when in use, the fastening tape is attached to the non-skin-facing surface of the abdominal side part and worn on the body.

[0049] While the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments and can be modified as appropriate within the scope that does not impair the intended effects of the present invention. For example, in the above embodiment, the shape of the opening 6 in plan view is rectangular, but in the present invention, the shape of the opening in plan view can be selected arbitrarily, and may be, for example, an ellipse elongated in the vertical direction. In addition, in the above embodiment, the planar shape of the absorbent core 5 was rectangular (a shape with a constant horizontal length), but in the present invention, the planar shape of the absorbent core can be selected arbitrarily, for example, it may be a shape in which the horizontal length varies in parts, a specific example of which is an hourglass shape with a narrowed portion in the crotch area. In the above embodiment, the diaper 1 includes the leakage preventing cuffs 10 and the leg cuffs 13 as longitudinally stretchable portions, but may include only one of them. In addition, in the above embodiment, the outer casing 20 was a split-type outer casing divided into a member 20A arranged on the ventral side and a member 20B arranged on the dorsal side, but it may also be an outer casing of a type that is continuous from the ventral portion A through the crotch portion C to the dorsal portion B. [Explanation of symbols]

[0050] 1,1A Disposable diapers (absorbent articles) 5 Absorbent Core 6 Openings 6C center opening 7 Core wrap sheet 7A Skin side sheet 7B Non-skin side sheet 8 Joint area 9 Non-bonded area 9A Anterior nonunion area 9B Posterior nonunion area 10 Leak-proof cuff (first vertically stretchable portion) 13 Leg cuff (second vertical stretch section) A Ventral part B Dorsal part C Inseam X vertical direction Y Horizontal CLx Vertical center line (imaginary line) CLy Horizontal center line (imaginary line)

Claims

1. It has a longitudinal direction corresponding to the front-to-back direction of the wearer and a transverse direction perpendicular thereto, and has an abdominal portion that is positioned on the wearer's abdominal side when worn, a dorsal portion that is positioned on the wearer's back side, and an inseam portion located between the abdominal portion and the dorsal portion. An absorbent article comprising an absorbent core that absorbs and retains bodily fluids, and a longitudinally stretchable portion that extends along the absorbent core in the longitudinal direction and is positioned around the wearer's legs when worn, The absorbent core has at least an opening in the crotch area that penetrates the absorbent core in the thickness direction and extends in the longitudinal direction, In the aforementioned opening, there is a bonding region between the skin-side sheet in contact with the skin-facing surface of the absorbent core and the non-skin-side sheet in contact with the non-skin-facing surface of the absorbent core, and a non-bonding region where the two sheets are not bonded to each other. The non-jointed region includes a front non-jointed region located on the longitudinal front end side of the opening and a rear non-jointed region located on the longitudinal rear end side of the opening. The aforementioned front non-jointed region is smaller in area than the aforementioned rear non-jointed region of the absorbent article.

2. The absorbent article according to claim 1, wherein the opening has a vertical length that is longer than its horizontal length.

3. The absorbent article according to claim 1 or 2, wherein, when the absorbent article is unfolded and in its maximum extended state, the lateral length of the opening is 20 mm or less.

4. The absorbent article according to claim 1 or 2, wherein, in the unfolded and fully extended state of the absorbent article, the vertical length of the opening is 2 / 3 or less of the vertical length of the absorbent core.

5. The absorbent article according to claim 1 or 2, wherein, in the unfolded and fully extended state of the absorbent article, the ratio of the area of ​​the front non-jointed region and the rear non-jointed region to the total area of ​​the opening is 3% or more.

6. The absorbent article according to claim 1 or 2, wherein, in the unfolded and fully extended state of the absorbent article, the longitudinal length of the bonded region is 1.5 times or more the longitudinal length of the non-bonded region.

7. The absorbent article according to claim 1 or 2, wherein, in the unfolded and fully extended state of the absorbent article, when the absorbent article is divided in two in the longitudinal direction and a virtual straight line extending in the transverse direction is drawn, the longitudinal length from the virtual straight line to the longitudinal rear end of the joining region is 80% or less of the longitudinal length from the virtual straight line to the longitudinal front end of the joining region.

8. The absorbent article according to claim 1 or 2, wherein, in the unfolded and fully extended state of the absorbent article, the vertical length of the overlapping portion in the vertical direction between the opening and the vertically expandable portion is 50% or more of the vertical length of the expandable region of the vertically expandable portion.

9. The absorbent article according to claim 1 or 2, wherein, in the unfolded and fully extended state of the absorbent article, the non-jointed region overlaps with the stretched region of the longitudinal stretchable portion, or is located further inward in the longitudinal and transverse directions than the stretched region.

10. The absorbent article according to claim 1 or 2, wherein the opening is positioned to align with a virtual straight line extending in the vertical direction, which bisects the absorbent article in the horizontal direction.

11. The absorbent article according to claim 1 or 2, wherein the openings are arranged in pairs on one side and the other side with respect to a virtual straight line that divides the absorbent article in the horizontal direction and extends in the vertical direction.

12. The absorbent article according to claim 11, wherein the absorbent core has a central opening that penetrates the absorbent core in the thickness direction and extends in the longitudinal direction at a position that coincides with the imaginary straight line between the pair of openings.

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