Absorbent articles

Abstract

To provide an absorbent article which does not block expansion of an absorbent core by a core wrap sheet.SOLUTION: An absorbent article has length along a longitudinal direction and length along a width direction orthogonal to the longitudinal direction, and includes: an absorber; a cover sheet arranged on a skin surface side of the absorber or outside in the width direction; a liquid-impermeable back sheet arranged on a non-skin surface side of the absorber; a joint part joining the cover sheet and the back sheet outside an end part in the width direction of the absorber; and a non-joint part to be a space formed between the end part in the width direction of the absorber and the joint part. The absorber has an absorbent core having SAP particles to be high absorbent polymer and a core wrap sheet composed integrally or separately and covering an external surface of the absorbent core. The core wrap sheet covering a side surface part of the absorbent core is formed by pulp fiber sheet, and rate of elongation of the core wrap sheet covering the skin surface side of the absorbent core is higher than rate of elongation of the core wrap sheet covering the side surface part of the absorbent core.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to an absorbent article. [[Background Art]]

[0002] Absorbent articles such as disposable diapers, absorbent pads and sanitary products have been developed. For example, an absorbent pad including a core wrap sheet covering an absorbent core has been proposed (Patent Document 1). [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2019-141118 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] Covering the absorbent core with the core wrap sheet can suppress deformation of the absorbent core. While the absorbent core covered with the core wrap sheet is easy to maintain its shape, its expansion after water absorption is suppressed. In a usage mode of an absorbent article in which discharged liquid repeatedly flows into the absorbent core, even though the absorbent core still has residual absorption capacity, expansion is inhibited by the core wrap sheet, so that the absorbent core cannot exhibit sufficient absorption capacity, and reversion of the unabsorbed liquid may occur, resulting in deterioration of wearing comfort.

[0005] An object of the present invention is to provide an absorbent article in which the core wrap sheet does not inhibit expansion of the absorbent core. [[Means for Solving the Problem]]

[0006] An absorbent article according to one aspect of the present invention is an absorbent article having a length along the longitudinal direction and a length along the width direction perpendicular to the longitudinal direction, comprising: an absorbent body; a covering sheet disposed on the skin side or the widthwise outer side of the absorbent body; a liquid-impermeable back sheet disposed on the non-skin side of the absorbent body; a joining portion that joins the covering sheet and the back sheet to each other on the outside of the widthwise end of the absorbent body; and a non-joint portion which is a space formed between the widthwise end of the absorbent body and the joining portion, wherein the absorbent body comprises an absorbent core having particles of SAP, which is a highly absorbent polymer, and a core wrap sheet which is integrally or separately formed and covers the outer surface of the absorbent core, wherein the core wrap sheet covering the side portion of the absorbent core is formed from a pulp fiber sheet, and the elongation rate of the core wrap sheet covering the skin side of the absorbent core is higher than the elongation rate of the core wrap sheet covering the side portion of the absorbent core. [Effects of the Invention]

[0007] According to the present invention, an absorbent article can be provided in which the core wrap sheet does not inhibit the expansion of the absorbent core. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an external perspective view of an absorbent pad according to the first embodiment. [Figure 2] Figure 2 is a plan view of the absorbent pad according to the first embodiment. [Figure 3] Figure 3 is a cross-sectional view of an absorbent pad according to the first embodiment. [Figure 4] Figure 4 is a cross-sectional view of an absorbent pad according to the second embodiment. [Figure 5] Figure 5 is a cross-sectional view of an absorbent pad according to the first application embodiment. [Figure 6] Figure 6 is a plan view of an absorbent pad according to a second application embodiment. [Figure 7] Figure 7 is a cross-sectional view of an absorbent pad according to a second application embodiment. [Figure 8]Figure 8 is a cross-sectional view of an absorbent pad according to a third application embodiment. [Figure 9] Figure 9 is a cross-sectional view of an absorbent pad according to a fourth application embodiment. [Modes for carrying out the invention]

[0009] The following describes an absorbent article according to an embodiment of the present invention with reference to the drawings. Note that the configurations of the following embodiments are illustrative, and the present invention is not limited to these embodiments.

[0010] <First Embodiment> In this embodiment, for a disposable absorbent pad (an example of an "absorbent article" as referred to in this application), the longitudinal direction is defined as the direction connecting the front panel, which is positioned opposite the wearer's abdomen, and the back panel, which is positioned opposite the wearer's back. Between these front panel (one side in the longitudinal direction) and back panel (the other side in the longitudinal direction) (in the center in the longitudinal direction), the inseam section, which is positioned between the wearer's legs (opposite the crotch), is connected. Furthermore, when the absorbent pad is worn by the wearer (hereinafter abbreviated as "wearing state"), the side facing the wearer's skin (inside in the wearing state) is defined as the skin side, and the side opposite the skin side (outside in the wearing state) is defined as the non-skin side. In addition, the direction connecting the skin side and the non-skin side is defined as the thickness direction, and the direction perpendicular to both the longitudinal direction and the thickness direction is defined as the width direction. Moreover, viewing from the thickness direction is defined as a plan view. The absorbent pad has a length along the longitudinal direction and a width along the width direction perpendicular to the longitudinal direction, and is attached between the wearer's legs. Furthermore, the terms relating to direction used in this application shall mean directions that coincide with the front, back, left, and right of the wearer when the absorbent pad 1 is worn by the wearer. For example, when the term "left and right direction" is used in this application, it means directions that coincide with the left and right of the wearer when the absorbent pad is worn by the wearer.

[0011] Figure 1 is an external perspective view of an absorbent pad according to the first embodiment. The absorbent pad 1 is used to absorb and retain liquids such as urine, and can be used alone by placing it on the skin-facing side of lower garments, or it can be used layered inside tape-type or pant-type disposable diapers. The absorbent pad 1 has a crotch area 1B that covers the wearer's genitals when worn, a front body area 1F located in front of the crotch area 1B and corresponding to the wearer's front body, and a back body area 1R located behind the crotch area 1B and corresponding to the wearer's back body. In plan view, the absorbent pad 1 according to this embodiment has a gourd shape in which the crotch area 1B is narrower on the front body area 1F and back body area 1R sides than the crotch area 1B. Also, comparing the width of the front body area 1F and the back body area 1R, the back body area 1R side is wider. This shape allows the absorbent pad 1 to conform more easily to the wearer's abdomen and buttocks when worn. The shape of the absorbent pad is not limited to a roughly gourd shape; for example, it may be roughly rectangular. Alternatively, it may have a paddle shape with a wider back section.

[0012] Figure 2 is a plan view of an absorbent pad according to the first embodiment. The absorbent pad 1 includes a top sheet 8 positioned on the skin-facing side when worn. The top sheet 8 is the part of the absorbent pad 1 that comes into contact with the wearer's skin (skin-facing surface) when worn, and is a water-permeable sheet made of a liquid-permeable material that allows liquids such as urine to pass through. Woven fabric, nonwoven fabric, porous film, etc. can be used for the top sheet 8. For the nonwoven fabric, a hydrophilic treatment of thermoplastic resin fibers such as polypropylene, polyethylene, polyester, and nylon may be used, or an air-through nonwoven fabric, point-bonded nonwoven fabric, spunbond nonwoven fabric, melt-blown nonwoven fabric, etc. may be used. The top sheet 8 is an example of a covering sheet in this disclosure.

[0013] The absorbent pad 1 includes an absorbent body 6 that absorbs liquids such as urine. The absorbent body 6 is positioned to include a crotch area 1B to absorb liquids discharged by the wearer. In this embodiment, The absorbent body 6 has an upper absorbent mat 6A positioned on the top sheet 8 side and a lower absorbent mat 6B positioned on the non-skin side as an absorbent core. In plan view, the upper absorbent mat 6A has a gourd shape, similar to the absorbent pad 1. The lower absorbent mat 6B is positioned below the upper absorbent mat 6A when viewed from the top sheet 8 side, and in plan view, it has a rectangular shape with the longitudinal direction of the absorbent pad 1 as its longer side. The upper absorbent mat 6A and the lower absorbent mat 6B are stacked in the thickness direction such that their respective width centers coincide approximately. Also, in plan view, the upper absorbent mat 6A is formed to be larger than the lower absorbent mat 6B. The longitudinal direction of the absorbent body 6 coincides with the longitudinal directions of the upper absorbent mat 6A and the lower absorbent mat 6B and the longitudinal direction of the absorbent pad 1. Note that the absorbent core may be composed of a single mat without the upper absorbent mat 6A and the lower absorbent mat 6B.

[0014] A back sheet 5 is provided on the non-skin side of the absorbent body 6. The back sheet 5 is a sheet formed from a thermoplastic, liquid-impermeable resin such as polyethylene film to suppress leakage of discharged liquid that flows into the absorbent body 6. The back sheet 5 may also be made of a material that has moisture permeability to suppress stuffiness when worn. In this embodiment, the width of the back sheet 5 is wider than the width of the absorbent body 6 and has substantially the same shape as the top sheet 8. The back sheet 5 and the top sheet 8 are joined at the widthwise ends. It is also possible to consider a configuration in which the width of the top sheet 8 is narrower than that of the back sheet 5, and the side sheets 9L and 9R, which will be described later, are joined to the back sheet 5.

[0015] An intermediate sheet (second sheet), not shown separately, may be provided between the top sheet 8 and the absorbent 6. If an intermediate sheet is provided, the same material as the top sheet 8 can be used for the intermediate sheet. Alternatively, materials such as pulp fibers or nonwoven fabrics that have liquid permeability and hydrophilicity may be used.

[0016] A cover sheet 4 is provided further on the non-skin side of the back sheet 5. The cover sheet 4 forms the exterior surface of the absorbent pad 1, and has rigidity capable of withstanding friction with diapers, underwear and the like used in combination. The cover sheet 4 generally uses a nonwoven fabric composed of synthetic fibers such as polypropylene, polyethylene, polyethylene terephthalate. The cover sheet 4 is liquid-impermeable, but may be liquid-permeable. When the back sheet 5 has moisture permeability, it is desirable that the cover sheet 4 also has moisture permeability.

[0017] A fastening tape may be provided on a part of the further non-skin side of the cover sheet 4. The fastening tape is an adhesive tape, which is adhered to underwear or disposable diapers, and prevents displacement between the absorbent pad 1 and the diaper, underwear or the like. Alternatively, without providing a fastening tape, a member having a large friction coefficient on the non-skin side may be adopted as the cover sheet 4 to suppress displacement relative to the diaper or the like. Furthermore, an anti-slip process such as applying a hot melt adhesive may be performed on the non-skin side of the cover sheet 4.

[0018] It is also conceivable to adopt a configuration in which the cover sheet 4 is not provided, and the back sheet 5 serves as the non-skin side surface. An absorbent pad is an absorbent article that needs to be replaced frequently. By not providing the cover sheet 4, the amount of materials can be reduced, and a low-priced absorbent pad can be provided.

[0019] Further, the absorbent pad 1 is provided with a pair of water-impermeable side sheets 9L, 9R arranged on the skin side on both sides in the width direction of the absorbent pad 1 and extending along the longitudinal direction. The side sheets 9L, 9R are arranged such that their longitudinal ends align with the longitudinal ends of the top sheet 8. The side sheets 9L, 9R have adhesive parts 9LA, 9RA arranged on the outer side in the width direction. The adhesive parts 9LA, 9RA are adhered to the top sheet 8, the absorbent body 6, and the back sheet 5, which are members arranged on the non-skin side (lower layer) thereof, by an adhesive such as hot melt. The top sheet 8 does not extend to the widthwise end of the absorbent pad 1, and the side shee The adhesive parts 9LA and 9RA of 9L and 9R are bonded to the back sheet 5 or the cover sheet 4.

[0020] Furthermore, the side sheets 9L and 9R each have free ends 9LB and 9RB located at one end on the inside in the width direction. Thread-like elastic members, thread rubber 3BL and 3BR, are attached to the free ends 9LB and 9RB in a stretched state along the longitudinal direction of the absorbent pad 1. Near the longitudinal ends, the free ends 9LB and 9RB are bonded to the top sheet 8 side, but on the longitudinal inside, the free ends 9LB and 9RB are not bonded to any part of the absorbent pad 1 and can stand upright on the skin side. As the thread rubber 3BL and 3BR contract, the free ends 9LB and 9RB stand upright on the skin side, using the upright lines 3LL and 3LR provided at the widthwise inside ends of the bonded parts 9LA and 9RA as the upright ends, forming three-dimensional gathers 3L and 3R. The upright three-dimensional gathers 3L and 3R obstruct the movement of discharged liquid outward in the width direction of the three-dimensional gathers 3L and 3R, suppressing lateral leakage of liquid. Side sheets 9L and 9R are also examples of covering sheets in this disclosure.

[0021] Figure 3 is a cross-sectional view of an absorbent pad according to the first embodiment. More specifically, it is a cross-sectional view of the absorbent pad when the central part is cut along the width direction. In the cross-sectional views shown below, each structure is shown as thicker than it actually is in order to make the internal structure of the absorbent pad 1 easier to understand, but in reality the absorbent pad 1 is very thin. The absorbent body 6 has an absorbent core 6C and a core wrap sheet 7 that covers the absorbent core 6C. The absorbent core 6C has a structure in which granular absorbent resin (super absorbent polymer) such as SAP (Super Absorbent Polymer), which is a hydrophilic polymer with a cross-linked structure that can absorb and retain water, is held in the gaps between short fibers of cellulosic fibers such as pulp fibers, rayon fibers, or cotton fibers, or short fibers of synthetic fibers such as polyethylene, polypropylene, or polyethylene terephthalate that have been treated to be hydrophilic.

[0022] In this embodiment, SAP particles refer to a resin composition containing SAP that has been made into granules. The term "resin composition containing SAP" here is a concept that encompasses both compositions consisting solely of SAP and compositions in which SAP is the main component and other substances are added to an extent that does not adversely affect water absorption. Examples of "other substances" include additives (such as surface modifiers added to hydrophobicize the particle surface) and unreacted monomers remaining after the synthesis of SAP. SAP particles can absorb liquids approximately 10 to 100 times their own weight (for example, 60 times in this embodiment). For example, granular SAP particles with a diameter of approximately 0.1 to 0.5 mm before liquid absorption may be used.

[0023] While SAP particles can gel and retain moisture, it takes a certain amount of time for them to absorb it. Therefore, while the SAP particles are absorbing the moisture, the short fibers slow down the discharged liquid and diffuse it within the absorption core 6C, allowing the discharged liquid to be absorbed by a wide area of ​​SAP particles, thereby suppressing backflow.

[0024] In this embodiment, the absorbent core 6C has a two-layer structure consisting of an upper absorbent mat 6A and a lower absorbent mat 6B. The upper absorbent mat 6A may be wider than the lower absorbent mat 6B throughout its entire extension region. In this case, when observed from the skin side, the lower absorbent mat 6B is contained within the width of the upper absorbent mat 6A. The upper absorbent mat 6A has a roughly gourd-shaped outer form and extends outward in the width direction of the vertical lines 3LL and 3RL in the front body region 1F and back body region 1R. Therefore, in the front body region 1F and back body region 1R, the upper absorbent mat 6A extends outward in the width direction of the three-dimensional gathers 3L and 3R. On the other hand, in the crotch region 1B, the upper absorbent mat 6A is narrowed in the width direction, and its end is contained within the vertical lines 3LL and 3LR of the three-dimensional gathers 3L and 3R.

[0025] The width of the lower absorbent mat 6B is less than or equal to that of the upper absorbent mat 6A throughout its entire extent. As a result, a space is created inside the absorbent core 6C where the upper absorbent mat 6A extends but the lower absorbent mat 6B does not. This space functions as a flow path for the discharged liquid absorbed by the absorbent core 6C. The discharged liquid can easily move longitudinally along this flow path. This configuration makes it possible to disperse the discharged liquid inside the absorbent core 6C, allowing for more efficient use of the absorbent core 6C's absorption capacity.

[0026] SAP particles may be predominantly arranged on either the upper absorbent mat 6A or the lower absorbent mat 6B. For example, SAP particles may be arranged only on the upper absorbent mat 6A and not on the lower absorbent mat 6B. In this case, the lower absorbent mat 6B consists only of short fibers and plays a role in holding, diffusing, and suppressing backflow of the inflowing wastewater until it is absorbed by the SAP particles contained in the upper absorbent mat 6A. The lower absorbent mat 6B also plays a role in moving excess wastewater to the flow channels at the widthwise ends and dispersing it in the longitudinal direction. In this embodiment, SAP particles are arranged between the upper absorbent mat 6A and the lower absorbent mat 6B, forming an SAP layer 6S with a very high SAP particle content. The SAP layer 6S is formed by fixing the SAP particles between the upper absorbent mat 6A and the lower absorbent mat 6B with a hot melt adhesive or the like. The SAP layer 6S has an SAP particle content of 80% or more, and efficiently captures and absorbs the discharged fluid moving between the upper absorbent mat 6A and the lower absorbent mat 6B. The SAP layer 6S may be placed in a location where a relatively large amount of discharged fluid is likely to be absorbed, such as near the wearer's urethral opening.

[0027] The absorbent body 6 according to this embodiment includes a core wrap sheet 7. The core wrap sheet 7 is a water-permeable sheet that covers the outer surface of the absorbent body 6, and more specifically, it covers the skin-facing side, non-skin-facing side, and side of the absorbent body 6. The core wrap sheet 7 is a sheet made of thin fibers, and as an example, a melt-through nonwoven fabric or a pulp fiber sheet such as tissue paper can be used. The core wrap sheet 7 protects the shape of the absorbent core 6C, which is composed of multiple absorbent mats, when it is not in contact with the discharged liquid, preventing deformation and preventing the escape of SAP particles contained in the absorbent mats. The SAP particles are arranged so that the absorbent pad 1 can properly perform its function, and if they deviate from their position, the absorbent pad 1 will not be able to properly perform its function. In addition, SAP particles that have not absorbed moisture are hard, sand-like particles, and if these escaped, unabsorbed SAP particles come into direct contact with the wearer's skin, they may cause discomfort to the wearer. For this reason, the absorbent core 6C is wrapped in the core wrap sheet 7 to prevent deformation of the absorbent core 6C and to prevent the escape of SAP particles. The core wrap sheet 7 may be configured as a single sheet that encloses the absorbent core 6C as a whole. However, since the roles that the core wrap sheet 7 should play differ on the skin-facing side, non-skin-facing side, and side of the absorbent core 6C, it is also possible to form it as a combination of separate sheet materials arranged according to the required functions.

[0028] On the other hand, SAP particles that have absorbed moisture expand to more than several tens of times their original size, so when they absorb wastewater, the absorbent core 6C expands significantly. However, since the absorbent core is covered by a core wrap sheet, the expansion of the absorbent core is suppressed by the core wrap sheet. If the SAP particles cannot expand, the absorption capacity of the absorbent core decreases, and there is a risk that it will not be able to absorb wastewater.

[0029] Therefore, in this embodiment, the top sheet 8 and the back sheet 5 are configured to be wider than the absorbent 6. Then, at the widthwise ends, the top sheet 8 or the side sheets 9L, 9R are joined to the back sheet 5 as covering sheets to form joints 6EL, 6ER. In the example shown in Figure 3, the top sheet 8 and the back sheet 5 are joined to each other to form joints 6EL, 6ER. For forming joints 6EL, 6ER, bonding with adhesives such as hot melt adhesive or heat welding can be used. The joints 6EL, 6ER are in the widthwise direction of the absorbent 6. The sheets covering the absorbent 6 are positioned at a distance of 2.5 mm to 10 mm from the edges. Between the widthwise edges of the absorbent 6 and the joints 6EL and 6ER, the sheets covering the absorbent 6 are not joined together, creating a space in which the contents of the expanded absorbent 6 can move in the width direction. In Figure 3, this space is shown as the non-jointed parts 6L and 6R.

[0030] When the top sheet 8 and the back sheet 5 are joined to each other to form joints 6EL and 6ER, the unjointed sections 6L and 6R are formed in the crotch area 1B. When the side sheets 9L and 9R and the back sheet 5 are joined to each other to form joints 6EL and 6ER, the joints 6EL and 6ER extend along the longitudinal direction of the absorber 6, and similarly, the unjointed sections 6L and 6R also extend along the longitudinal direction of the absorber 6. Even when the top sheet 8 is used as a covering sheet in the crotch area 1B and the back sheet 5 is joined to each other to form joints 6EL and 6ER, in the front body area 1F and the back body area 1R, the top sheet 8 and the back sheet 5 may not be joined, and the side sheets 9L and 9R may be used as covering sheets and joined to each other to form joints 6EL and 6ER. Such a complex configuration can also realize unjointed sections 6L and 6R that extend along the longitudinal direction of the absorber 6.

[0031] Non-joint portions 6L and 6R are provided further outside the widthwise ends of the absorbent body 6, and the core wrap sheet 7 is constructed with separate sheets at least on the skin-facing side and the non-skin-facing side of the absorbent core 6C, with the sheet covering the non-skin-facing side and the sides of the absorbent core 6C being a pulp fiber sheet such as tissue paper. With this configuration, the absorbent core 6C, upon receiving body pressure or absorbing excretory fluid, expands in the widthwise direction, causing the sides of the core wrap sheet 7 to break and reach the non-joint portions 6L and 6R. By providing the non-joint portions 6L and 6R, a region in which the absorbent core 6C can expand is secured, thereby further increasing the absorption capacity of the absorbent body 6.

[0032] In this embodiment, the absorbent core 6C is covered by four separate core wrap sheets 7. Each core wrap sheet is made of a different material. For example, the upper core wrap sheet 7T, which covers the skin-facing side of the absorbent core 6C, is made of an air-through nonwoven fabric. The air-through nonwoven fabric has a pleasant feel against the skin, excellent water permeability, and allows discharged liquids to pass through easily. Furthermore, because the air-through nonwoven fabric is made of resin, it stretches under tension and does not break. Due to this characteristic, the upper core wrap sheet 7T can easily follow the stretching of the skin-facing side of the absorbent core 6C in the width direction, such as when body pressure is applied to the absorbent pad 1. The upper core wrap sheet 7T protects the skin-facing side of the absorbent core 6C and does not break under tension, thus effectively suppressing leakage of SAP particles to the skin side.

[0033] Of the core wrap sheets 7, the lower core wrap sheet 7B covering the non-skin side of the absorbent core 6C may be made of an air-through nonwoven fabric, but it may also be made of a pulp fiber sheet such as tissue paper that has a certain tensile strength and stretches to a certain extent under tension. Since the non-skin side of the absorbent pad 1 has a back sheet 5, which is a non-permeable film, and a cover sheet 4 that improves the feel against the skin laminated on it, the need to prevent leakage of SAP particles is lower compared to the skin side. For this reason, tissue paper that stretches to a certain extent under tension may be used instead of expensive air-through nonwoven fabric. The lower core wrap sheet 7B is intermittently joined to the back sheet 5 with an adhesive such as a hot melt adhesive.

[0034] Of the core wrap sheets 7, the side core wrap sheets 7S cover both sides of the absorbent core 6C. The side core wrap sheets 7S have a roughly U-shaped cross-section that extends to the widthwise ends of the absorbent body 6 on both the skin-facing and non-skin-facing sides. The side core wrap sheets 7S are joined to the upper core wrap sheet 7T at both widthwise ends on the skin-facing side of the absorbent body 6 using an adhesive such as a hot melt adhesive. In addition, the side core wrap sheets 7S are joined to the lower core wrap sheet at both widthwise ends on the non-skin-facing side of the absorbent body 6 using an adhesive such as a hot melt adhesive. It is joined to 7B. The side core wrap sheet 7S is made of a material with low strength and low elongation, such as tissue paper, and easily breaks as the absorbing core 6C expands outward in the width direction.

[0035] Based on measurements according to JIS L1096 (Method A), the side core wrap sheet 7S has a lower tensile elongation rate (%) compared to the upper core wrap sheet 7T. When body pressure is applied to the absorbing core 6C, the absorbing core 6C expands in the width direction, and the side core wrap sheet 7S, which has a lower elongation rate than the core wrap sheets 7 in other parts and breaks easily, breaks under load due to the expansion of the absorbing core 6C. As already explained, on the outer side in the width direction of the side core wrap sheet 7S, the top sheet 8 or side sheets 9L,9R are joined to the back sheet 5 as covering sheets to form joints 6EL,6ER, and in the gap of 2.5 mm to 10 mm in the width direction between these joints 6EL,6ER and the absorbing core 6C, non-jointed sections 6L,6R are provided, which are spaces formed between the covering sheet and the back sheet 5. The absorbing core 6C can distribute body pressure by breaking the side core wrap sheet 7S and entering the non-jointed sections 6L,6R. Furthermore, the non-jointed sections 6L and 6R provide room for expansion when they absorb discharged fluid. Side sheets 9L and 9R are positioned on the skin-facing side of the non-jointed sections 6L and 6R, and the back sheet 5 is positioned on the non-skin-facing side. Therefore, even if the side core wrap sheet 7S ruptures, SAP particles will not leak out onto the skin side.

[0036] Furthermore, the side core wrap sheet 7S can also be made from tissue paper without added paper strength enhancers. Paper, being an aggregate of plant fibers, easily unravels when it comes into contact with liquid, returning to its original loose fibrous state. However, by adding a paper strength enhancer during the papermaking process, the fibers become less likely to unravel when in contact with liquid, making it more resistant to breakage. When the discharged liquid reaches the widthwise edge of the absorbent core 6C, the side core wrap sheet 7S will come into contact with the liquid. In this case, if a paper strength enhancer has not been added to the side core wrap sheet 7S, the fibers of the side core wrap sheet 7S will unravel and it will easily break.

[0037] As mentioned above, the absorbent core 6C holds the wastewater by trapping the incoming effluent with SAP particles contained within, and the SAP particles themselves expand to several tens of times their original size. In this process, the absorbent core 6C itself also expands significantly. If the absorbent core does not expand enough to rupture the core wrap sheet, even if the SAP particles themselves have remaining absorption capacity, there will be no area to expand further, and the core will be unable to absorb any more wastewater.

[0038] By using a material that easily ruptures upon contact with liquid for the side core wrap sheet 7S, the side core wrap sheet 7S becomes more prone to rupture upon contact with the discharged liquid. The aforementioned non-joint portions 6L and 6R are provided on the outer side in the width direction of the side core wrap sheet 7S. When the side core wrap sheet 7S ruptures, the absorbent core 6C can continue to expand toward the non-joint portions 6L and 6R, enabling it to absorb more discharged liquid.

[0039] In this embodiment, an SAP layer 6S with a very high SAP particle content is placed between the upper absorbent mat 6A and the lower absorbent mat 6B. The SAP particle content of the SAP layer 6S is 80% or more. The wastewater that has permeated over the upper absorbent mat 6A is captured by the SAP layer, and a portion of it moves to the lower absorbent mat 6B side, while another portion moves outward in the width direction along the SAP layer 6S, causing the SAP particles contained in the SAP layer 6S to expand. In addition, the SAP particles that have absorbed the wastewater and expanded sufficiently in the SAP layer 6S move outward in the width direction along the gap between the upper absorbent mat 6A and the lower absorbent mat 6B. In this way, by providing the SAP layer 6S between the upper absorbent mat 6A and the lower absorbent mat 6B, the absorbent core 6C becomes more likely to expand outward in the width direction, making it easier to rupture the side core wrap sheet 7S.

[0040] As described above, in the first embodiment, the absorbent core 6C is structured to easily expand outward in the width direction when it absorbs wastewater, and the core wrap sheet 7 covering the absorbent core 6C is composed of four separate sheets, of which the side core wrap sheet 7S covering the side of the absorbent core 6C is configured to easily break due to the pressure caused by the expansion of the absorbent core 6C. The top sheet 8 or side sheets 9L, 9R are joined to the back sheet 5 as covering sheets to form joints 6EL, 6ER, and non-jointed portions 6L, 6R, which are spaces formed between the covering sheet and the back sheet 5, are provided in the gap of 2.5 mm to 10 mm in the width direction between the joints 6EL, 6ER and the absorbent core 6C. When the absorbent core 6C expands in the width direction and the side core wrap sheet 7S breaks, the absorbent core 6C can further expand toward the non-jointed portions 6L, 6R. The absorbent pad 1 according to the first embodiment is suitable because it can exhibit the absorption performance of the absorbent core 6C itself without being hindered by the core wrap sheet 7.

[0041] <Second Embodiment> Figure 4 is a cross-sectional view of an absorbent pad according to the second embodiment. In the following description, components having substantially the same function as those in the first embodiment are denoted by the same reference numerals in each figure, and their descriptions are omitted. In the second embodiment, the core wrap sheet 7 is composed of two separate sheets: an upper core wrap sheet 7T that covers the skin-facing side of the absorbent core 6C, and a lower core wrap sheet 7B that covers the side and non-skin-facing sides of the absorbent core 6C. That is, unlike the first embodiment, the side core wrap sheet 7S and the lower core wrap sheet 7B are integrally formed from a single sheet.

[0042] The upper core wrap sheet 7T and the lower core wrap sheet 7B may be made of different materials. For example, as in the first embodiment, the upper core wrap sheet 7T is made of an air-through nonwoven fabric and has a higher elongation rate than the lower core wrap sheet 7B. This elongation rate was measured based on JIS L1096 (Method A), as in the first embodiment. On the other hand, the lower core wrap sheet 7B is made of tissue paper. As in the first embodiment, a paper strength enhancer may not be added to the lower core wrap sheet 7B. The lower core wrap sheet 7B covers the absorbent core 6C in a roughly C-shape from the non-skin side, covering both sides of the absorbent core 6C, and is further superimposed on the upper core wrap sheet 7T on the skin side of the absorbent core 6C, and is joined with an adhesive such as a hot melt adhesive.

[0043] In the second embodiment, unlike the first embodiment, there is no side core wrap sheet 7S designed to withstand rupture. On the other hand, as in the first embodiment, non-joint portions 6L and 6R are provided on the sides of the absorbent core 6C. The lower core wrap sheet 7B is more prone to rupture than the upper core wrap sheet 7T. When the lower core wrap sheet 7B ruptures on the side of the absorbent core 6C, the absorbent core 6C can expand to the non-joint portions 6L and 6R without being restricted in its expansion, thus effectively absorbing the discharged liquid. Furthermore, in the second embodiment, since the lower core wrap sheet 7B is made of the same material as the sides of the absorbent core 6C, it is also prone to rupture on the non-skin side. When the lower core wrap sheet 7B ruptures, the absorbent core 6C can expand not only on the sides but also between itself and the back sheet 5 on the non-skin side. Therefore, the absorbent pad 1 according to the second embodiment has a greater degree of freedom in expansion and can fully demonstrate its absorption performance.

[0044] As shown in Figure 4, the lower core wrap sheet 7B is joined to the back sheet 5 by an adhesive such as a hot melt adhesive. The hot melt adhesive is arranged in a dotted line pattern in the longitudinal direction. Therefore, in the absorbent pad 1 according to the second embodiment, even the areas where the hot melt adhesive is not applied can function as a flow path for the discharged liquid, which is preferable. Furthermore, there is no need to prepare a material to form the side core wrap sheet 7S, and the side core wrap sheet 7S is joined to the upper core wrap sheet 7T and the lower core wrap sheet 7B. Since the process is eliminated, manufacturing costs can be reduced.

[0045] <First Application Embodiment> Figure 5 is a cross-sectional view of an absorbent pad according to the first application embodiment. The application embodiments described below illustrate the application of the second embodiment described above. Of course, the matters disclosed in the following application embodiments are also applicable to the first embodiment. In this application embodiment, the absorbent core 6C has a two-layer structure consisting of an upper absorbent mat 6A and a lower absorbent mat 6B, but no SAP layer 6S is placed between the upper absorbent mat 6A and the lower absorbent mat 6B. When SAP particles come into contact with liquid, they expand and gel, which can cause a so-called gel-blocking phenomenon that inhibits the movement of the liquid that subsequently permeates through. When the gel-blocking phenomenon occurs, the movement of the discharged liquid between the upper absorbent mat 6A and the lower absorbent mat 6B is suppressed, and the function of the absorbent core 6C may be inhibited. Therefore, in this first application embodiment, the SAP layer 6S is not placed, and the absorbent core 6C is formed so that the discharged liquid can permeate through the entire core and expand.

[0046] In this first application embodiment, the core wrap sheet 7 is configured to be most easily broken at the widthwise end of the absorbent core 6C. In this embodiment as well, non-joint portions 6L and 6R are formed on the widthwise outer side of the absorbent core 6C, similar to the first embodiment. The expanded absorbent core 6C can break the core wrap sheet 7 at the side portion of the absorbent core 6C and expand further toward the non-joint portions 6L and 6R. In this way, the absorbent pad 1 according to the first application embodiment can also ensure the fluidity of the discharged liquid inside the absorbent core 6C by not providing an SAP layer 6S, while still exhibiting absorption performance without being hindered by the breaking of the core wrap sheet 7.

[0047] <Second Application Embodiment> Figure 6 is a plan view of an absorbent pad according to a second application embodiment. A groove 6H is provided in the center of the width direction of the absorbent pad on the skin side, extending in the longitudinal direction of the absorbent pad 1. The groove 6H corresponds to the midline of the human body. Discharged fluids such as urine flow into the groove 6H, move along the groove 6H in the longitudinal direction, and are rapidly absorbed over a wide area in the longitudinal direction of the absorbent pad 6. Therefore, the absorbent pad 1 according to this embodiment can rapidly diffuse discharged fluids by having a groove 6H. As shown in the figure, the groove 6H does not reach the longitudinal end of the absorbent pad 6. Therefore, discharged fluids that move outward in the longitudinal direction do not reach the longitudinal end of the absorbent pad 6, but remain inside the groove 6H and are absorbed sequentially.

[0048] The upper absorbent mat 6A is provided with grooves 6H. The shape of the grooves 6H can be arbitrary, but in this embodiment, in a plan view, the grooves 6H have a rectangular shape with both the front and rear ends formed in an arc shape. The front end of the grooves 6H is located in the middle of the front body area 1F, and the rear end of the grooves 6H is located at the front of the back body area 1R. The grooves 6H also have a certain width. For example, the width is 20 mm to 35 mm. The length of the grooves 6H is 245 mm to 355 mm. An absorbent pad 1 with grooves 6H of this size is suitable for adults. Note that in a plan view, the grooves 6H may be formed in a shape other than a rectangle, such as a polygon or an ellipse.

[0049] Furthermore, the extension of the groove 6H in the absorbent pad 1 includes the area corresponding to the wearer's urethral opening where urination occurs. The groove 6H is formed to include this area in order to facilitate the flow of urine generated by the wearer. When the absorbent pad 1 is viewed from above, this area is defined, for example, at a position 60% of the longitudinal length of the upper absorbent mat 6A, extending forward from the rear end of the upper absorbent mat 6A. For example, if the longitudinal length of the upper absorbent mat 6A is 500 mm, the area near 300 mm forward from the rear end of the upper absorbent mat 6A corresponds to the urethral opening.

[0050] Liquids such as urine released from the wearer flow through the groove 6H and diffuse longitudinally. Furthermore, because the extent of the groove 6H corresponds to the urethral opening, the area near the wearer's urethra becomes moist quickly when discharge occurs. As a result, the wearer is less likely to experience discomfort.

[0051] Figure 7 is a cross-sectional view of an absorbent pad according to a second application embodiment. In this application embodiment, the groove 6H is a compression groove that does not penetrate the upper absorbent mat 6A. The discharge fluid generated from the urethral opening first falls into the groove 6H, which is a slit, and moves longitudinally within the slit, being absorbed over a wide area in the longitudinal direction of the upper absorbent mat 6A. By providing the groove 6H, the discharge fluid is absorbed in a specific area, preventing the SAP particles from becoming saturated, and at the same time, the absorbent capacity of the absorbent core 6C can be accurately exercised even at a position away from the urethral opening.

[0052] In this diagram, the top sheet 8 is configured not to fall into the groove 6H. Similarly, the upper core wrap sheet 7T is configured not to fall into the groove 6H. However, the configuration of the sheets constituting the skin-facing side of the absorbent core 6C is not necessarily limited to this, and configurations in which the upper core wrap sheet 7T, or both the top sheet 8 and the upper core wrap sheet 7T, fall into the groove 6H are also conceivable. By allowing the sheets constituting the skin-facing side of the absorbent core 6C to fall into the groove 6H, the drained liquid can flow into the groove 6H more effectively. When the sheets fall into the groove 6H, the fallen portion may be the entire groove 6H, or only a part of it may fall into the groove 6H.

[0053] In this application embodiment, liquids such as urine excreted on the upper absorbent mat 6A can be guided to the lower absorbent mat 6B through the thinned portion of the groove 6H. In this way, the absorbent pad 1 according to this application embodiment can effectively absorb liquids such as excreted fluids with an absorbent core 6C having an upper absorbent mat 6A and a lower absorbent mat 6B.

[0054] <Third Application Embodiment> Figure 8 is a cross-sectional view of the absorbent pad according to the third application embodiment. In the second application embodiment, the groove 6H was a compression groove formed by compressing the upper absorbent mat 6A, but in the third application embodiment, the groove 6H is a through groove that penetrates the upper absorbent mat 6A. That is, in the longitudinal center of the absorbent pad 1, the upper absorbent mat 6A is divided into left and right sections in the width direction by the groove 6H. In the third application embodiment, the discharged liquid that flows into the groove 6H is absorbed by the upper absorbent mats 6A on both sides as it falls, but reaches the lower absorbent mat 6B directly and is held there. In addition, a portion of the discharged liquid spreads around the surface of the lower absorbent mat 6B and is also absorbed by the SAP layer 6S. As already mentioned, the lower absorbent mat 6B contains almost no SAP particles, and the lower absorbent mat 6B has the function of temporarily holding the discharged liquid, slowing it down, and diffusing it. Furthermore, it is possible to move the discharged liquid that has reached the widthwise end of the lower absorbent mat through the channel formed between the upper absorbent mat 6A and the core wrap sheet 7 to a position where absorption capacity remains. As in the second application embodiment, the upper core wrap sheet 7T, or the top sheet 8 and the upper core wrap sheet 7T, may fall into the groove 6H.

[0055] <Fourth Application Embodiment> Figure 9 is a cross-sectional view of an absorbent pad according to the fourth application embodiment. In the fourth application embodiment, the groove 6H penetrates not only the upper absorbent mat 6A but also the lower absorbent mat 6B. That is, the groove 6H is a through groove that penetrates the entire absorbent core 6C. The groove 6H provided in the lower absorbent mat 6B is provided so as to overlap the groove 6H provided in the upper absorbent mat 6A in the thickness direction, but its width may be narrower than the groove 6H provided in the upper absorbent mat 6A. In this application embodiment, the discharged liquid that flows into the groove 6H is absorbed by the upper absorbent mat 6A and the lower absorbent mat 6B on both sides as it falls down. Furthermore, while being absorbed by the SAP layer 6S provided at the boundary between the upper absorbent mat 6A and the lower absorbent mat 6B, it reaches the boundary region with the back sheet 5, which is the non-skin side end of the absorbent body 6. Between the absorbent body 6 and the back sheet 5, an adhesive such as a hot melt adhesive is arranged in a scattered manner in the longitudinal direction. The discharged liquid that reaches this region moves longitudinally through a channel between the absorbent body 6 and the back sheet 5, and is reabsorbed into the absorbent core 6C at a position where the absorption capacity is still high. In this way, in the fourth application embodiment, the absorbent body 6 can diffuse and absorb the discharged liquid by utilizing the overall structure of the absorbent pad 1. As with the second and third application embodiments, the upper core wrap sheet 7T, or the top sheet 8 and the upper core wrap sheet 7T, may fall into the groove 6H.

[0056] Although various embodiments and application embodiments have been described above, the present invention is not limited to the embodiments described above. For example, multiple grooves 6H may be provided parallel to the longitudinal direction. Also, the tip of the groove 6H may be bent. If the tip of the groove 6H is bent, the bend can slow down the discharged liquid when it flows vigorously in the longitudinal direction along the groove 6H, thereby reducing the possibility of leakage from the stomach or back.

[0057] This invention is applicable not only to absorbent pads, but also to pull-up diapers and tape-type diapers for infants or adults.

[0058] The features included in each embodiment and its modified form disclosed above can be combined in any way. [Explanation of symbols]

[0059] 1. Absorbent pad 1F ··Front bodice area 1B...Inseam area 1R · Back panel area 3BL, 3BR... elastic thread 3LL,3RL··Rise line 3L, 3R... 3D Gathered 4. Cover Sheet 5. Back seat 6. Absorbent 6C Absorption Core 6A ··Upper layer absorbent mat 6B ·· Lower layer absorption mat 6S··SAP layer 6H·Groove 6L,6R··Non-joint part 6EL,6ER··Joint part 7. Core Wrap Sheet 7T... Upper core wrap sheet 7B · Lower core wrap sheet 7S ·· Side core wrap sheet 8. Top sheet 9L, 9R... Side seats 9LA,9RA·Adhesive part 9LB,9RB··Free end

Claims

1. An absorbent article having a length along its longitudinal direction and a length along its width direction perpendicular to the longitudinal direction, absorbent material, A covering sheet disposed on the skin-facing side or the outer side in the width direction of the absorbent body, A liquid-impermeable backsheet is placed on the non-skin side of the absorbent, A joint portion is provided on the outer side of the widthwise end of the absorbent, which joins the covering sheet and the back sheet together. The non-joint portion is a space formed between the end of the absorber in the width direction and the joint portion, Equipped with, The absorbent body is An absorption core having particles of SAP, a highly absorbent polymer, Composed as an integral or separate unit, the core wrap sheet covers the outer surface of the absorption core, It has, The core wrap sheet covering the side portion of the absorbent core is formed from a pulp fiber sheet. The elongation rate of the core wrap sheet covering the skin-facing side of the absorbent core is higher than the elongation rate of the core wrap sheet covering the side portion of the absorbent core. At least a portion of the core wrap sheet is rupturable by the pressure caused by the expansion of the absorbing core. Absorbent material.

2. The absorption core is provided with grooves extending in the longitudinal direction. The absorbent article according to claim 1.

3. The core wrap sheet comprises an upper core wrap sheet covering the skin-facing side of the absorbent core, a side core wrap sheet covering the side portion of the absorbent core, and a lower core wrap sheet covering the non-skin-facing side of the absorbent core. At least the upper core wrap sheet and the lower core wrap sheet are separate components. The lower core wrap sheet and the side core wrap sheet are composed of pulp fiber sheets. At the widthwise end of the upper core wrap sheet, the upper core wrap sheet and the side core wrap sheet are joined together. The absorbent article according to claim 1.

4. The aforementioned upper core wrap sheet is formed from an air-through nonwoven fabric. The absorbent article according to claim 3.

5. The elongation rates of the upper core wrap sheet and the lower core wrap sheet are higher than the elongation rate of the side core wrap sheet. The absorbent article according to claim 3.

6. The side core wrap sheet and the lower core wrap sheet are formed from a single sheet. The absorbent article according to claim 3.

7. The absorbent core is laminated in the thickness direction and comprises at least an upper absorbent mat positioned on the skin side and a lower absorbent mat positioned on the non-skin side. The aforementioned lower absorbent mat contains pulp fibers. The absorbent article according to any one of claims 1 to 6.

8. A layer having a particle content of 80% or more of the SAP is disposed between the upper absorbent mat and the lower absorbent mat. The absorbent article according to claim 7.

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