Absorbent article
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KAO CORP
- Filing Date
- 2023-08-29
- Publication Date
- 2026-06-19
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to an absorbent article. [Background technology]
[0002] In general, pants-type disposable diapers are provided with an absorbent body including an absorbent core that serves as a main liquid absorbing portion. It is also known that the absorbent core is provided with slits in consideration of wearing comfort, etc. For example, Patent Document 1 describes an absorbent article in which a central slit is formed in the center of the absorbent core in the width direction and side slits are formed on both sides of the central slit. The document also describes that the absorbent core has a two-layer structure consisting of a first layer and a second layer disposed on the non-skin-facing side of the first layer. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] JP 2012-187152 A Summary of the Invention [Problem to be solved by the invention]
[0004] Patent Document 1 describes that when the disposable diaper of the same document is worn, the central slit portion deforms so as to become convex toward the wearer and form a top surface, while the side slit portions deform so as to become convex toward the non-skin facing surface, so that the cross section of the absorbent body along the width direction becomes W-shaped. The disposable diaper of the same document deforms at the side slit portions so as to become convex toward the non-skin facing surface. However, the disposable diaper in Cited Document 1 fits the absorbent body around the buttocks of the wearer in the vicinity of the buttocks to reduce the wearing comfort and the occurrence of leakage. Even if the cross section of the absorbent body along the width direction has a portion that deforms into a W-shape, there is still room for improvement in terms of the wearing comfort in the crotch area. Furthermore, in order to improve the fit in the crotch area, it is possible to provide the absorbent body with multiple vertical slits. However, simply increasing the number of slits may result in a decrease in the absorption capacity in the crotch area, making leakage more likely to occur.
[0005] An object of the present invention is to provide an absorbent article having excellent absorption performance and a comfortable fit in the crotch area. [Means for solving the problem]
[0006] The present invention relates to an absorbent article comprising an absorbent body having an absorbent core, a top sheet arranged on the skin-facing side of the absorbent body, and a back sheet arranged on the non-skin-facing side of the absorbent body. In one embodiment, the absorbent article comprises a ventral portion arranged on the ventral side of the wearer, a dorsal portion arranged on the dorsal side of the wearer, and a crotch portion located between the ventral portion and the dorsal portion, and preferably has a vertical direction corresponding to the direction extending from the ventral portion through the crotch portion to the dorsal portion, and a horizontal direction perpendicular to the vertical direction. In one embodiment, the absorbent core preferably has a two-layer structure including an upper absorbent core and a lower absorbent core located on the non-skin-facing side of the upper absorbent core. In one embodiment, the absorbent core has a central fold guide portion in the center in the horizontal direction, and side fold guide portions on either side of the central fold guide portion, and it is preferable that the central fold guide portion and the side fold guide portions each extend in the vertical direction. In one embodiment, it is preferable that the central fold guide portion has an upper central through hole that penetrates the upper absorbent core in the thickness direction but does not penetrate the lower absorbent core, and the side fold guide portion has a lower through hole that penetrates the lower absorbent core in the thickness direction. In one embodiment, it is preferable that a particulate water-absorbing polymer is disposed in the upper central through-hole and the lower through-hole. In one embodiment, the basis weight of the water-absorbent polymer in the upper central through-hole is preferably higher than the basis weight of the water-absorbent polymer in the lower through-hole. Effect of the Invention
[0007] According to the present invention, an absorbent article having excellent absorption performance and a comfortable fit in the crotch area is provided. [Brief description of the drawings]
[0008] [Figure 1] FIG. 1 is a schematic perspective view showing a pants-type disposable diaper according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic partially cutaway plan view of the underpants-type disposable diaper shown in FIG. 1 in an unfolded and extended state, as viewed from the skin-facing surface side. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a schematic diagram showing a lateral cross section of an absorbent core of the disposable diaper in a worn state taken at a position P1 in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. A disposable diaper 1 (hereinafter, also referred to as diaper 1) according to one embodiment of the present invention is a so-called pants-type diaper, and as shown in Figures 1 to 3, comprises an absorbent body 5 having a liquid-permeable top sheet 2, a liquid-impermeable or water-repellent back sheet 3, and a vertically elongated absorbent body 4 disposed between these sheets 2, 3, and an outer packaging material 10 positioned on the non-skin-facing side of the absorbent body 5 and fixing the absorbent body 5. The absorbent body 4 contains an absorbent core 40 that is elongated in the same direction as the absorbent body 4. 1 and 2, the diaper 1 has a ventral portion A arranged on the ventral side of a wearer when worn, a crotch portion C arranged in the crotch portion, and a dorsal portion B arranged on the dorsal side. The diaper 1 has a longitudinal direction X corresponding to the front-to-rear direction of the wearer, i.e., the direction extending from the ventral portion A through the crotch portion C to the dorsal portion B, and a lateral direction Y perpendicular to the longitudinal direction X. The longitudinal direction X coincides with the longitudinal direction of an absorbent main body 5, which will be described later. The outer packaging material 10 has both side edges of the abdominal portion A and both side edges of the dorsal portion B joined together, thereby forming a pair of side seal portions S,S, a waist opening 7, and a pair of leg openings 8,8 in the diaper 1. The absorbent article of the present invention is preferably a pants-type article, and pants-type absorbent articles include pants-type diapers, as well as pants-type incontinence pads and sanitary napkins.
[0010] In this specification, the "skin-facing side" refers to the side of the disposable diaper or its constituent members (e.g., the topsheet 2) that faces the wearer's skin when the disposable diaper is worn, i.e., the side relatively closer to the wearer's skin, and the "non-skin-facing side" refers to the side of the disposable diaper or its constituent members that faces the side opposite the skin side when the disposable diaper is worn, i.e., the side relatively farther from the wearer's skin. Note that "when worn" or "worn state" refers to the normal, proper wearing position, i.e., the state in which the disposable diaper is maintained in the correct wearing position.
[0011] 2, the diaper 1 is formed symmetrically with respect to a vertical centerline CLy that extends in the vertical direction X and bisects the diaper 1 in the horizontal direction Y in an unfolded and stretched state. The horizontal centerline CLx is an imaginary straight line that bisects the diaper 1 in the vertical direction X in an unfolded and stretched state and extends in the horizontal direction Y. The "unfolded and stretched state" of the diaper 1 refers to a state in which the diaper 1 is unfolded by separating it at the side seal portions S, S described below, and the diaper 1 in the unfolded state is stretched to the design dimensions (the same dimensions as when the diaper 1 is unfolded flat with all the influence of the elastic members completely eliminated). In this specification, each dimension of each part of the diaper 1, such as the length in the vertical direction X or the horizontal direction Y, refers to the dimension (design dimension) when the elastic members in each part are stretched and each member is stretched, unless otherwise specified.
[0012] The absorbent core 40 in the diaper 1 is configured to include a two-layer structure consisting of an upper absorbent core 411 and a lower absorbent core 412 disposed on the non-skin-facing side of the upper absorbent core 411. The upper absorbent core 411 is generally T-shaped in plan view with a ventral portion A in the longitudinal direction X being wider in the lateral direction Y than the other portions, and is shorter in the longitudinal direction X than the lower absorbent core 412 and shorter in the lateral direction Y than the lower absorbent core 412. The lower absorbent core 412 has a larger area in plan view than the upper absorbent core 411. The upper absorbent core 411 entirely overlaps the lower absorbent core 412 in plan view, and the lower absorbent core 412 forms the contour of the absorbent core 40. The upper absorbent core 411 is disposed from the crotch portion C to the abdominal portion A of the diaper 1, and the width of the upper absorbent core 411 gradually increases from near the center of the crotch portion C in the longitudinal direction X of the diaper toward the abdominal portion A. The lower absorbent core 412 extends vertically through the crotch portion C to the abdominal portion A and the back portion B.
[0013] The absorbent core 40 has an upper central through-hole 47 and a lower through-hole 48. The upper central through-hole 47 is a through-hole that passes through the upper absorbent core 411 in the thickness direction Z but does not pass through the lower absorbent core 412, and is located at the center of the upper absorbent core 411 in the lateral direction Y. The upper central through-hole 47 does not pass through the lower absorbent core 412, and more preferably does not extend into the lower absorbent core 412. In other words, it is preferable that the portion of the lower absorbent core 412 that overlaps with the upper central through-hole 47 and the portions located on both sides of the upper central through-hole 47 form a flat surface. The lower through-holes 48 are through-holes that penetrate the lower absorbent core 412 in the thickness direction Z, and are located on both sides of the upper central through-hole 47. The upper central through-hole 47 and the lower through-hole 48 are each formed to extend in the vertical direction X. The length of each of these through-holes 47, 48 in the vertical direction X is longer than the length in the horizontal direction Y, and the length in the vertical direction X is usually 3 to 100 times, and preferably 5 to 50 times, the length in the horizontal direction Y. The planar shapes of the upper central through-hole 47 and the lower through-hole 48 may be any shape extending in the vertical direction X, and may each be a vertically elongated band or an ellipse extending in the vertical direction X. In this embodiment, the upper central through-hole 47 has a rectangular shape in the planar view, and the lower through-holes 48 each have an isosceles trapezoid shape with its lower base (a side longer than its upper base) located outward in the horizontal direction Y in the planar view.
[0014] As shown in Fig. 3, the absorbent core 40 has a central fold guide portion 43 at a position overlapping with the upper central through-hole 47 in a plan view of the diaper 1. Also, on both sides of the central fold guide portion 43, the absorbent core 40 has side fold guide portions 44 at positions overlapping with the lower through-holes 48 in a plan view of the diaper 1. The central fold guide portion 43 and the side fold guide portions 44 each extend in the vertical direction X. The central fold guide portion 43 and the side fold guide portions 44 of the present invention enhance the flexibility of the absorbent core 40 in the horizontal direction Y. The side fold guide portions 44 are disposed at positions not overlapping with the upper absorbent core 411 in a plan view.
[0015] In the diaper 1 of this embodiment, as shown in Fig. 3, the water-absorbent polymers 17, 18 are disposed in the upper central through-hole 47 and the lower through-hole 48. The water-absorbent polymers 17, 18 are disposed by dispersing particulate water-absorbent polymers in the upper central through-hole 47 and the lower through-hole 48. The method of disposing the water-absorbent polymers 17, 18 in the upper central through-hole 47 and the lower through-hole 48 is preferably, but not limited to, dispersing after the through-holes are formed. The water-absorbent polymer is preferably disposed in the through-holes with a sheet such as a core wrap sheet disposed so as to cover one side of the opening of the through-hole.
[0016] The water-absorbing polymers 17 and 18 may generally be hydrogel materials capable of absorbing and retaining water, such as polymers or copolymers of acrylic acid or alkali metal salts of acrylic acid. Examples of such polymers include polyacrylic acid and its salts, and polymethacrylic acid and its salts, specifically, partial sodium salts of acrylic acid polymers. The shape of the water-absorbing polymers 17 and 18 is not particularly limited, and may be, for example, spherical, tufted, lumpy, bale-shaped, fibrous, irregular, or particles of a combination thereof.
[0017] In addition, it is preferable that the basis weight of the water-absorbent polymer 17 in the upper central through-hole 47 is higher than the basis weight of the water-absorbent polymer 18 in the lower through-hole 48. In other words, it is preferable that the basis weights of the water-absorbent polymers 17 and 18 in the through-holes satisfy the magnitude relationship represented by the following formula. Upper center through hole 47>lower through hole 48 The basis weight of the water-absorbing polymer 17 in the upper central through hole 47 is preferably 70 g / m 2 More than 250g / m 2 Less than 80 g / m 2 More than 240g / m 2 The basis weight of the water-absorbing polymer 18 in the lower through-hole 48 is preferably 10 g / m 2 More than 150g / m 2 Less than 20 g / m 2 More than 100g / m 2 The following is the result. Furthermore, the basis weight of the absorbent polymer 18 in the lower through hole 48 is preferably 20% or more, more preferably 30% or more, and also preferably 80% or less, more preferably 70% or less, and also preferably 20% or more and 80% or less, more preferably 30% or more and 70% or less, relative to the basis weight of the absorbent polymer 17 in the upper central through hole 47. It is preferable that the basis weight of the water-absorbent polymer 18 in each of the lower through-holes 48 located on both sides of the upper central through-hole 47 is lower than the basis weight of the water-absorbent polymer 17 in the upper central through-hole 47 .
[0018] The basis weight of the water-absorbent polymers 17, 18 in the upper central through-hole 47 and the lower through-hole 48 can be measured as follows. <Method of Measuring Basis Weight of Water-Absorbent Polymer 17 in Upper Central Through-Hole 47> First, the absorbent body 4 is taken out by removing the members other than the absorbent body 4, such as the top sheet 2. Next, the core wrap sheet 45 on the skin-facing side is cut out from the portion where the upper central through hole 47 and the core wrap sheet 45 overlap when the absorbent body 4 is viewed in a plan view, and the water-absorbent polymer 17 is taken out from the upper central through hole 47 by, for example, turning the absorbent body 4 upside down. If the water-absorbent polymer 17 is attached to the cut-out core wrap sheet 45, the core wrap sheet 45 is immersed in a solvent, for example, to dissolve the adhesive, and the water-absorbent polymer 17 is separated from the core wrap sheet 45. The mass of the water-absorbent polymer 17 taken out from the entire area of the upper central through hole 47, including the water-absorbent polymer 17 separated in this way, is measured. Then, the basis weight of the water-absorbent polymer 17 in the upper central through hole 47 is calculated by dividing the mass of the water-absorbent polymer 17 by the area of the upper central through hole 47 in a plan view. <Method of Measuring Basis Weight of Water-Absorbent Polymer 18 in Lower Through-Hole 48> First, the absorbent body 4 is taken out by removing the members other than the absorbent body 4, such as the top sheet 2. Next, the core wrap sheet 45 on the skin-facing side and the non-skin-facing side is cut out from the portion where the lower through-hole 48 and the core wrap sheet 45 overlap when the absorbent body 4 is viewed in a plane, and the water-absorbent polymer 18 is taken out from the lower through-hole 48. If the water-absorbent polymer 18 is attached to the cut-out core wrap sheet 45, the core wrap sheet 45 is immersed in a solvent or the like to dissolve the adhesive, and the water-absorbent polymer 18 is separated from the core wrap sheet 45. The mass of the water-absorbent polymer 18 taken out from the entire area of the lower through-hole 48, including the water-absorbent polymer 18 separated in this way, is measured. Then, the basis weight of the water-absorbent polymer 18 in the lower through-hole 48 is calculated by dividing the mass of the water-absorbent polymer 18 by the area of the lower through-hole 48 in a plane view.
[0019] In the absorbent core 40 in this embodiment, the upper absorbent core 411 and the lower absorbent core 412 are each made of a fiber aggregate made of a fiber material such as defibrated pulp and a functional material such as particles of water-absorbing polymer. The absorbent body 4 is made by covering the upper absorbent core 411 and the lower absorbent core 412 having such a configuration entirely with a core wrap sheet 45. As the core wrap sheet 45, various known materials can be used, and for example, thin paper such as tissue paper or water-permeable nonwoven fabric is preferably used. The absorbent body 4 may be made by covering the upper absorbent core 411 and the lower absorbent core 412 with core wrap sheets separately and then laminating them. In this case, the core wrap sheet covering the upper absorbent core 411 and the core wrap sheet covering the lower absorbent core 412 may or may not be bonded to each other. Furthermore, after one of the upper absorbent core 411 and the lower absorbent core 412 is covered with a core wrap sheet, the entirety of the covered and uncovered sides can be further covered with a core wrap sheet. It is preferable for the absorbent polymer 17 in the upper central through hole 47 to be arranged under a sheet such as the core wrap sheet 45 arranged on the skin-facing side of the upper central through hole 47, in order to ensure the absorption capacity of the crotch area.
[0020] The upper central through hole 47 in the central fold guide section 43 and the lower through hole 48 in the side fold guide section 44 form a through hole that penetrates the upper absorbent core 411 and a through hole that penetrates the lower absorbent core 412, as shown in Figures 2 and 3. The absorbent core 40 is formed by manufacturing the upper absorbent core 411 and the lower absorbent core 412 each having a through hole, spraying the water-absorbent polymers 17, 18 into the upper central through hole 47 and the lower through hole 48, and laminating both absorbent layers. Alternatively, the upper absorbent core 411 and the lower absorbent core 412 may be manufactured each without a through hole, forming a through hole in each of them, spraying the water-absorbent polymers 17, 18 into the upper central through hole 47 and the lower through hole 48, and laminating both absorbent layers.
[0021] As shown in FIG. 2, the absorbent body 4 in the diaper 1 of this embodiment has a region R1 (hereinafter also referred to as the parallel region R1) in the absorbent core 40 in the crotch portion C, in which a central fold guide portion 43 and a pair of side fold guide portions 44, 44 are parallel to each other in the longitudinal direction X of the absorbent core 40.
[0022] As shown in FIG. 4, when the diaper 1 of this embodiment is worn, the absorbent core 40 in the parallel region R1 is bent into a W shape such that the central fold guide portion 43 becomes a peak and the side fold guide portions 44, 44 become valleys. By bending the absorbent core 40 into a W-shape in the crotch portion C, the absorbent core 40 flexibly deforms in response to pressure applied by the wearer's legs E, reducing the pressure applied to the legs and the resulting resistance and discomfort. In addition, the side portions 46 outward of the side fold guide portions 44 in the lateral direction Y of the absorbent core 40 stand up, and their ends are positioned along the wearer's skin, preferably the groin, thereby providing good side leakage prevention. In addition, the portion of the absorbent main body 5 having the central fold guide portion 43 easily comes into close contact with the wearer's urination area, so that urine is smoothly absorbed into the absorber 4 and the absorbent core 40. Moreover, since the upper central through-hole 47 in the central folding guide portion 43 is formed in the upper absorbent core 411 and the water-absorbent polymer 17 is disposed in the upper central through-hole 47, even when the central folding guide portion 43 is deformed to form a peak facing the wearer, a space can be secured for the water-absorbent polymer 17 to absorb water and swell, and the water-absorbent polymer 17 can easily exhibit its original absorption performance, so that even when a large amount of urine is excreted at one time, the urine can be absorbed by the particles of the water-absorbent polymer 17. Therefore, excellent fit and wearing comfort in the crotch area as well as excellent absorption performance can be obtained. Furthermore, the upper central through-hole 47 and the lower through-hole 48 function as paths for excrement such as urine that is to be absorbed by the absorbent 4, promoting the diffusion of excrement in the planar direction and contributing to effective use of the liquid absorption performance of the absorbent 4. This can prevent urine from flowing on the skin or top sheet and leaking out from the front, or prevent urine flowing backward from mixing with feces, making the feces more likely to adhere to the skin.
[0023] In order to obtain such an effect more reliably, the length L1 (see FIG. 2) of the parallel region R1 in the longitudinal direction X of the absorbent core 40 is preferably 30% to 70% of the length Lc (see FIG. 2) of the crotch portion C in the longitudinal direction X of the diaper, more preferably 35% to 65%, and even more preferably 38% to 62%.
[0024] The side fold guide portion 44 may be disposed at a position overlapping the upper absorbent core 411 in a plan view, but in this embodiment, as described above, the side fold guide portion 44 is disposed at a position not overlapping the upper absorbent core 411 in a plan view. This increases the difference in rigidity between the central fold guide portion 43 and the side fold guide portion 44, and has the effect of making the side portions 46 easier to stand up and fit better around the crotch.
[0025] As shown in Fig. 2 and Fig. 3, the absorbent core 40 in the diaper 1 has a central region 41 in the center of the absorbent core 40 in the lateral direction Y, and has side regions 42 on both sides of the central region 41. The central region 41 is a portion where an upper absorbent core 411 is layered on a lower absorbent core 412, and the side regions 42 are portions that are thinner than the central region 41. As shown in Fig. 2, the diaper 1 of this embodiment has an upper absorbent core 411 that is generally T-shaped in plan view and is wider on the abdominal side A side, and a rectangular lower absorbent core 412 that is larger in dimensions in the longitudinal direction X and the lateral direction Y than the upper absorbent core 411, and the portion where the upper absorbent core 411 is layered on the lower absorbent core 412 is the central region 41, and the portion where the upper absorbent core 411 is not layered on the lower absorbent core 412 is the side region 42. The upper absorbent core 411 is disposed from the crotch portion C to the abdominal portion A of the diaper 1, and the width of both the upper absorbent core 411 and the central region 41 gradually increases from near the center of the crotch portion C in the longitudinal direction X of the diaper towards the abdominal portion A.
[0026] The absorbent core 40 has a central region 41 where the upper absorbent core 411 and the lower absorbent core 412 overlap, and side regions 42 that are thinner than the central region 41, thereby ensuring cushioning properties and bodily fluid absorption performance. That is, by making the side regions 42 thinner than the central region 41, when the diaper 1 is worn and the side regions 42 are pressed against the inner thighs of the wearer, the thin side regions 42 reduce discomfort such as a feeling of pressure or discomfort caused by the inner thighs being pressed down, and suppress the wearer from feeling uncomfortable. Furthermore, the central region 41 has a sufficient thickness, so that a sufficient absorption capacity can be ensured.
[0027] Thus, from the viewpoint of ensuring the body fluid absorption performance of the diaper 1, the thickness T1 of the central region 41 is preferably 5 mm or more, and more preferably 6 mm or more. Also, from the viewpoint of the fit of the diaper 1, the thickness T1 of the central region 41 is preferably 18 mm or less, and more preferably 17 mm or less. Taking these into consideration, the thickness T1 of the central region 41 is preferably 5 mm or more and 18 mm or less, and more preferably 6 mm or more and 17 mm or less. In order to improve the cushioning properties of the diaper 1 against body fluids, the thickness T2 of the side regions 42 is preferably 17 mm or less, and more preferably 16 mm or less. In order to ensure the absorption performance of the diaper 1, the thickness T2 of the side regions 42 is preferably 3 mm or more, and more preferably 4 mm or more. Taking these into consideration, the thickness T2 of the side region 42 is preferably 3 mm or more and 17 mm or less, and more preferably 4 mm or more and 16 mm or less. The thickness T2 of the side region 42 is preferably 16% or more, more preferably 17% or more, and preferably 95% or less, more preferably 94% or less, and preferably 16% or more and 95% or less, more preferably 17% or more and 94% or less, of the thickness T1 of the central region 41. The thickness T1 of the central region 41 is the thickness of the portion other than the upper central through-hole 47. The thickness T2 of the side region is the thickness of the portion other than the lower through-hole , i.e., the thickness of the side portion .
[0028] From the viewpoint of ensuring the absorption capacity of the diaper 1, it is preferable that in the crotch portion C, the length W4 in the lateral direction Y of the upper central through-hole 47 is shorter than the length W5 in the lateral direction Y of the lower through-hole 48. With this configuration, the absorption capacity in the crotch portion C can be ensured, so that even if a large amount of urine is excreted at one time, the urine can be reliably absorbed by the particles of the water-absorbent polymers 17, 18. In order to obtain such an effect more reliably, the length W4 in the horizontal direction Y of the upper central through hole 47 is preferably 3 mm or more, more preferably 4 mm or more, and preferably 20 mm or less, more preferably 19 mm or less, preferably 3 mm or more and 20 mm or less, more preferably 4 mm or more and 19 mm or less. The length W5 of the lower through hole 48 in the horizontal direction Y is preferably 5 mm or more, more preferably 6 mm or more, and preferably 25 mm or less, more preferably 24 mm or less, preferably 5 mm or more and 25 mm or less, more preferably 6 mm or more and 24 mm or less. The length W4 in the horizontal direction Y of the upper central through hole 47 is preferably 30% or more, more preferably 35% or more, and preferably 90% or less, more preferably 85% or less, relative to the length W5 in the horizontal direction Y of the lower through hole 48, and is preferably 30% or more and 90% or less, more preferably 35% or more and 85% or less. Furthermore, the width W4 of the upper central through-hole 47 which becomes the central fold guide portion 43 is preferably 5% to 40% of the width W3 of the central region 41 in the crotch portion, and more preferably 7% to 35%.
[0029] The central fold guide portion 43 and the side fold guide portion 44 preferably have different bending stiffnesses. In particular, the side fold guide portion 44 preferably has a smaller bending stiffness than the central fold guide portion 43. Since the side fold guide portion 44 of the absorbent core 40 has a smaller bending stiffness than the central fold guide portion 43, the pair of side portions 46, 46 can be easily deformed to be raised toward the wearer's skin, and the space between the wearer's crotch portion and the crotch portion C of the diaper 1 can be efficiently secured, thereby improving the efficiency of absorbing bodily fluids of the diaper 1. Furthermore, since the space under the crotch can be easily secured, the leakage of excrement from the diaper 1 can be further suppressed. From the same viewpoint as above, it is preferable that the bending stiffness of each of the central folding guide portion 43 and the side folding guide portions 44 is within the following ranges. The bending rigidity of the side fold guide portion 44 is preferably 0.1% to 30% of the bending rigidity of the central fold guide portion 43, and more preferably 0.2% to 25%. The bending rigidity of the central folding guide portion 43 is preferably 10 g / 30 mm or more and 200 g / 30 mm or less, and more preferably 15 g / 30 mm or more and 190 g / 30 mm or less. The bending rigidity of the side folding guide portion 44 is preferably 0.1 g / 30 mm or more and 0.2 g / 30 mm or less, and more preferably 20 g / 30 mm or more and 18 g / 30 mm or less. The bending stiffness can be measured by the following method.
[0030] <Method of measuring bending stiffness> The bending stiffness of the absorbent core is measured by measuring the three-point bending stiffness. First, the absorbent body 4 is removed from the diaper 1, and a measurement sample having a side length of 30 mm is cut out from the absorbent body 4. If the absorbent body 4 includes a core wrap sheet 45, the measurement sample is cut out together with the core wrap sheet 45. The measurement sample is cut out from the entire thickness of the absorbent body 4. Next, the measurement sample is stretched between a pair of plate-shaped supports. The supports are spaced apart by 10 mm, and the stretching direction is along the horizontal direction Y. A plate-shaped indenter is pressed into the measurement sample from above the measurement sample stretched between the supports. The plate-shaped indenter has a width of 2 mm, and its length in the pressing direction is longer than the length (30 mm) of the measurement sample. The position at which the plate-shaped indenter is pressed in is the middle position between the pair of supports in a plan view. The plate-shaped indenter is pressed 8 mm into the supports, and the maximum value of the load generated during the pressing is defined as the bending stiffness (g / 30 mm). A handle-ometer is used to measure the bending stiffness. It can be determined that the smaller the bending stiffness value, the higher the flexibility, i.e., the lower the bending stiffness.
[0031] From the viewpoint of making it easier for the pair of side portions 46, 46 to deform so as to be raised toward the wearer's skin, it is preferable that the side fold guide portion 44 does not include a fiber aggregate made of a fiber material such as defibrated pulp. In this specification, "not included" means that it is substantially not included. In other words, the side fold guide portion 44 is a portion in which there is no fiber aggregate made of a fiber material such as defibrated pulp, or the basis weight of the fiber aggregate made of a fiber material such as defibrated pulp is significantly lower than that of other portions. In other words, the side fold guide portion 44 may not include a fiber aggregate made of a fiber material such as defibrated pulp, or may be a portion in which there is a fiber aggregate made of a fiber material such as defibrated pulp, but the basis weight is significantly lower than that of other portions.
[0032] In the central region 41, it is preferable that the basis weight of the central fold guide portion 43 is lower than the basis weight of the portion other than the central fold guide portion 43. By having the basis weight of the central fold guide portion 43 lower than the basis weight of the portion other than the central fold guide portion 43, the absorbent core 40 can be more easily bent into a W shape. In the central region 41, the basis weight of the central fold guide portion 43 is preferably 20% or more, more preferably 25% or more, and preferably 70% or less, more preferably 65% or less, and preferably 20% or more and 70% or less, more preferably 25% or more and 65% or less, of the basis weight of the parts other than the central fold guide portion 43.
[0033] In order to more reliably absorb urine into each particle of the water-absorbent polymers 17, 18 even when a large amount of urine is excreted at once, the basis weight of the water-absorbent polymer 17 in the upper central through hole 47 is preferably 120% or more, more preferably 140% or more, and preferably 300% or less, more preferably 280% or less, and also preferably 120% or more and 300% or less, and more preferably 140% or more and 280% or less, of the basis weight of the water-absorbent polymer 18 in the lower through hole 48. The basis weight of the water-absorbing polymer 17 in the upper central through hole 47 is preferably 50 g / m 2 More preferably, 60 g / m 2 More preferably, it is 200 g / m 2 Less than 180 g / m 2 Less than or equal to 50 g / m 2 More than 200g / m 2 More preferably, it is 60 g / m 2 More than 180g / m 2 The following is the result. The basis weight of the water-absorbing polymer 18 in the lower through-hole 48 is preferably 10 g / m 2 More preferably, 15 g / m 2 More preferably, it is 150 g / m 2 Less than 140g / m 2 Less than or equal to 10 g / m 2 More than 150g / m 2 More preferably, it is 15 g / m or less. 2 More than 140g / m 2 The following is the result.
[0034] In this embodiment, the absorbent body 4 is preferably formed with recesses 15, 16 recessed toward the non-skin facing side as shown in Fig. 3. In this embodiment, the recesses 15, 16 are formed at positions overlapping the central fold guide portion 43 and the side fold guide portion 44 in a plan view, and the sheet covering the skin facing side of the absorbent core 40 is formed recessed toward the non-skin facing side. In this embodiment, the recesses 15, 16 are formed by recessing the top sheet 2 and the core wrap sheet 45, but only the core wrap sheet 45 may be formed recessed. The recesses 15, 16 formed on the skin facing side of the diaper 1 can effectively prevent the inconvenience of excrement flowing outward in the lateral direction Y from the diaper 1 (so-called lateral leakage). In order to further enhance the above-mentioned effects, it is preferable that depth T4 of recess 16 in side fold guide portion 44 is greater than depth T3 of recess 15 in central fold guide portion 43. The depth T4 of the recess 16 in the side folding guide portion 44 is preferably 0.5 mm or more and 8 mm or less, and more preferably 1 mm or more and 7 mm or less. The depth T3 of the recess 15 in the central folding guide portion 43 is preferably 0 mm or more and 4 mm or less, and more preferably 0.1 mm or more and 3 mm or less.
[0035] <Method for measuring the depth of the recess> First, the absorbent body 4 removed from the diaper 1 is cut at the center position in the longitudinal direction X of the parallel region R1 along the transverse direction Y of the diaper 1. The cut surface is magnified and observed using a microscope, and the depths of the recesses 15 and 16 on the cut surface are measured. Depth T3 of recess 15 is measured by defining an imaginary line Q1 connecting the left and right side edges 15a, 15a of recess 15, and measuring the distance from deepest part 15b of recess 15 to imaginary line Q1 along the thickness direction Z. Depth T4 of recess 16 is measured by defining an imaginary line Q2 connecting the left and right side edges 16a, 16a of recess 16, and measuring the distance from deepest part 16b of recess 16 to imaginary line Q2 along the thickness direction Z. Side edge 15a of recess 15 and side edge 16a of recess 16 refer to the positions where the sheet covering the skin-facing surface of absorbent core 40 starts to sink toward the non-skin-facing surface.
[0036] From the viewpoint of improving the absorption performance of bodily fluids, it is preferable that, on the ventral part A side in the longitudinal direction X of the absorbent core 40, the central folding guide part 43 extends from the positions of the ends 44a, 44a of the side folding guide parts 44 toward the ventral part A side, and extends from the longitudinal center of the absorbent body 4 toward the dorsal part B side. With such a configuration, urine taken into the absorbent body 4 or the absorbent core 40 is diffused toward the ventral part A side and the dorsal part B side, and the absorption capacity of not only the ventral part A side of the absorbent core 40 but also the dorsal part B side is effectively utilized. This increases the amount of urine that the diaper 1 can absorb without leaking, and urine leakage is less likely to occur even when the diaper 1 is worn for a long time or when the amount of urination is large. Moreover, since urine is taken into the absorbent body 4 or the absorbent core 40 and diffused, problems such as wetness and rash caused by contact between the skin and urine can be reduced. In order to obtain such an effect more reliably, the central fold guide portion 43 has an extension length L2 (see FIG. 2) from the position of the end portion 44a on the abdominal side of the side fold guide portion 44, which is preferably 5 mm or more and 40 mm or less, more preferably 10 mm or more and 35 mm or less. The central fold guide portion 43 has an extension length L10 (see FIG. 2) from the imaginary straight line CLx, which is preferably 5 mm or more and 40 mm or less, more preferably 6 mm or more and 35 mm or less. In terms of the relationship with the length Lc of the crotch portion C, the extension length L10 is preferably 2% or more and 10% or less, more preferably 3% or more and 9% or less of the length Lc of the crotch portion C.
[0037] From the viewpoint of forming a concave pocket capable of holding feces well near the excretion area, it is preferable that the side folding guide portions 44, 44 extend toward the back side B side from the end portion 43b of the central folding guide portion 43 and extend toward the back side B side from the center of the absorbent body 4 in the longitudinal direction X of the absorbent core 40. With this configuration, the absorbent core 40 on the back side B side of the parallel region R1 in the longitudinal direction X of the diaper is bent at the side folding guide portions 44, 44 without bending at the central folding guide portion 43 when the diaper is worn. Therefore, a portion where the absorbent core 40 is bent concavely toward the skin side is generated near the excretion area (anus) behind the parallel region R1, and thus an upward pocket capable of holding feces well is formed between the wearer's skin and the absorbent body. Furthermore, with regard to urine, the presence of the parallel region R1 and the central bent guide portion 43 in front of it allows the urine to be quickly absorbed by the absorbent body 4 or the absorbent core 40 and guided forward, making it less likely for the urine to mix with the feces. This prevents or significantly reduces the discomfort caused by feces sticking to the skin and the labor required to wipe off feces that has adhered to the skin. It also has excellent properties for preventing feces from leaking.
[0038] In order to obtain such an effect more reliably, the side fold guide portion 44 has an extension length L6 (see FIG. 2) from the position of the end portion 43b on the back side of the central fold guide portion 43 of 20 mm to 100 mm, more preferably 25 mm to 90 mm. In addition, in relation to the length Lc of the crotch portion C, the extension length L6 is preferably 10% to 40% of the length Lc, more preferably 12% to 38%.
[0039] From the same viewpoint, the distance L7 (see FIG. 2) of the back side end 43b of the central fold guide portion 43 from the back side B is preferably 80 mm or more and 150 mm or less, more preferably 85 mm or more and 145 mm or less. From the same viewpoint, the distance L8 (see FIG. 2) of the back side end 43b of the central fold guide portion 43 from the waist portion end 7b on the back side B side is preferably 30% or more and 60% or less, more preferably 35% or more and 55% or less of the total length L (see FIG. 2) of the diaper.
[0040] In addition, the position of the end 44b on the back side of the side fold guide portion 44 is preferably such that the distance L9 (see Figure 2) from the back side portion B is 5% or more and 25% or less of the length Lc (see Figure 2) of the crotch portion C, and more preferably 7% or more and 23% or less.
[0041] In order to more reliably obtain one or more of the above-mentioned effects, the width W1 (see FIG. 3) between the outer edge of the side fold guide portion 44 and the side edge of the absorbent core 40 is preferably 10% to 30% of the width W2 (see FIG. 3) of the absorbent core 40, more preferably 12% to 25%. The width W3 (see FIG. 3) of the central region 41 is preferably 20% to 65% of the width W2 of the absorbent core 40, more preferably 25% to 60%. The widths of these portions and their relationships with each other are preferably satisfied at least in the center of the crotch portion C in the longitudinal direction X, and are preferably satisfied over a range of 20 mm or more in the longitudinal direction X of the absorbent core, centered on the center of the crotch portion C in the longitudinal direction X.
[0042] 2 and 3, in the diaper 1 of this embodiment, elastic members 9 for raising the side portions 46 of the absorbent core 40 are arranged along both side edges of the absorbent core 40 in the longitudinal direction X. The elastic members 9 are arranged in a stretched state along the inner and / or outer surface of the core wrap sheet 45 that covers the absorbent core 40, and both ends are fixed to the abdominal side portion A and the back side portion B. Furthermore, leak-preventing cuffs 6, 6 are formed on both sides of the absorbent main body 5. The leak-preventing cuffs 6 include a leak-preventing cuff-forming sheet 60 joined to the absorbent main body 5, a leak-preventing cuff-forming elastic member 61 fixed in a stretched state near the free end of the leak-preventing cuff-forming sheet 60, and a leak-preventing cuff intermediate elastic member 62 fixed in a stretched state between the fixed end and the free end of the leak-preventing cuff 6. In the example shown in FIG. 2, the leak-proof cuff-forming sheet 60 is a two-layered sheet obtained by folding a strip-shaped water-repellent sheet of a predetermined width in half along its longitudinal direction X and bonding the opposing layers together with a hot melt adhesive, partial heat sealing, ultrasonic sealing, or the like, and the aforementioned elastic members 61, 62 are fixed in a stretched state between the layers of this two-layered sheet.
[0043] In addition, the top sheet 2 covers the skin-facing side of the absorbent core 40, and its both side end portions 21, 21 are joined and fixed to the back sheet 3 and the leak-proof cuff forming sheet 60 on the non-skin-facing side of the absorbent core 40 by known joining means such as an adhesive such as heat sealing.
[0044] As shown in Figures 2 and 3, the outer packaging material 10 is made up of two outer packaging material-forming sheets 11, 12 and elastic members for each portion fixed in a stretched state between these two sheets. That is, between the two outer packaging material-forming sheets 11, 12, a waist portion elastic member 71 which forms waist gathers on the periphery of the waist opening 7, a leg portion elastic member 81 which forms leg gathers on the periphery of the leg openings 8, and a waist circumference elastic member 91 which forms waist circumference gathers divided into left and right parts at the waist circumference portion D are each joined and fixed in a stretched state by any joining means such as a hot melt adhesive. Both of the outer packaging material forming sheets 11, 12 are made of nonwoven fabric. One or both of these two sheets are folded back at the peripheral edge of the waist opening 7, and the folded back portions are fixed to the skin-facing side of the absorbent main body 5 at the front and rear ends of the absorbent main body 5.
[0045] In the parallel region R1, from the viewpoint of deforming the absorbent core 40 into a W-shaped cross section as shown in FIG. 4 and forming a concave pocket in the absorbent core 40 behind the parallel region R1, it is preferable to arrange elastic members having the effect of pulling up or pushing up the side portions 46 of the absorbent core 40, such as the elastic members 9 and 61, 62 described above, on both sides of the absorbent main body 5 or on the leakproof cuffs 6 that are arranged so as to overlap partially with both sides of the absorbent main body 5. However, even if there is no elastic member along the longitudinal direction X of the absorbent core 40, the absorbent core 40 can be deformed into a W-shaped cross section as shown in Fig. 4 in the parallel regions R1 and into a shape forming a concave pocket behind the parallel regions R1 due to the force exerted by gripping and pulling up the widthwise central portion of the abdominal portion A of the diaper when putting on the diaper, or the force exerted from the wearer's thighs on both sides of the crotch portion C when wearing the diaper. Therefore, the presence of an elastic member along the longitudinal direction X of the absorbent core 40 is not essential.
[0046] The material from which the diaper 1 is made will now be described. As the material for each part of the diaper 1, various materials used for the corresponding parts of conventional disposable diapers can be used without any particular limitation. For example, the top sheet 2 can be a hydrophilic and liquid-permeable nonwoven fabric or a resin film with holes formed therein, and the back sheet 3 can be a moisture-permeable or moisture-impermeable resin film or a laminate of the resin film and a nonwoven fabric. Examples of fibers constituting the fiber assembly constituting the absorbent core 40 include hydrophilic fibers such as pulp fibers, rayon fibers, cotton fibers, and cellulose acetate; polyolefin fibers such as polyethylene and polypropylene; and condensation fibers such as polyester and polyamide. The fiber assembly is preferably obtained through a fiber stacking process in which fiber materials supplied on an air flow are sucked and stacked in a recess of a predetermined shape. The fiber assembly may be a mixture of a functional material and a fiber material. The functional material may be held in a form sandwiched between two fiber assemblies or in a form mixed and stacked and held between fibers. The functional materials such as fibers and water-absorbing polymers may each be used alone or in combination of two or more kinds. Examples of water-absorbing polymers include particles made of sodium polyacrylate, (acrylic acid-vinyl alcohol) copolymers, sodium polyacrylate crosslinks, (starch-acrylic acid) graft copolymers, (isobutylene-maleic anhydride) copolymers and their saponification products, and polyaspartic acid.
[0047] The sheet 60 for forming the leak-proof cuffs may be a multi-layered composite nonwoven fabric made of spunbond, meltblown, spunbond, etc., a spunbond nonwoven fabric, a heat-bonded nonwoven fabric, an air-through nonwoven fabric, etc. The elastic members arranged in each part are preferably in the form of a thread (e.g., rubber thread), a strip of a given width (e.g., flat rubber), etc., and thread-like members are particularly preferred. Examples of materials for the elastic members arranged in each part include natural rubber, synthetic rubber such as styrene-butadiene, butadiene, isoprene, and neoprene, EVA, elastic polyolefin, and urethane.
[0048] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.
[0049] For example, the disposable diaper of the present invention may be a pants-type disposable diaper with a divided outer packaging material in which the outer packaging material is divided into a dorsal sheet member arranged on the dorsal side of the wearer and a ventral sheet member arranged on the ventral side, the dorsal sheet member and the ventral sheet member are joined to form a tube by a pair of side seals, and the absorbent main body is fixed between the dorsal sheet member and the ventral sheet member. Also, the disposable diaper of the present invention may be a so-called flat-type disposable diaper in which a fastening tape is provided on the dorsal portion and the fastening tape is fastened to a landing tape provided on the outer surface of the ventral portion. In the flat-type disposable diaper, the portion on both side edges of the crotch portion is formed with a concave cutout portion so as to fit the shape of the leg circumference, and the portions located in front of and behind the concave cutout portion are the dorsal portion and the ventral portion.
[0050] Also, the elastic member 9 in the diaper 1 of the above-mentioned embodiment may be omitted, and the elastic member 62 arranged in the leakage preventing cuffs 6, 6 or the leakage preventing cuffs themselves may also be omitted. Also, a pair of side gathers extending outward from each of both side edges in the longitudinal direction X of the absorbent core 40 may be formed in the absorbent main body 5, and the elastic members arranged in the side gathers may be used as elastic members for raising the side portions of the absorbent core 40. [Explanation of symbols]
[0051] 1. Disposable diapers 2 Surface sheet 3 Back sheet 4. Absorber 5. Absorbent body 6 Leak proof cuff 7 Waist opening 8 Leg Opening 9 Elastic Members 10 Outer packaging material 15,16 Depression 17,18 Water-absorbent polymers 40 Absorbent Core 41 Central area 42 Side Area 43 Center bending guide section 44 Side folding guide section 45 Core wrap sheet 46 Side part 47 Upper center through hole 48 Lower through hole 60 Leak-proof cuff forming sheet 411 Upper absorbent core 412 Lower absorbent core A Ventral part B Dorsal part C Inseam S Side seal part
Claims
1. The absorbent body comprises an absorbent core having an absorbent material, a surface sheet disposed on the skin-facing side of the absorbent material, and a back sheet disposed on the non-skin-facing side of the absorbent material. An absorbent article comprising an abdominal portion positioned on the wearer's abdominal side, a dorsal portion positioned on the wearer's back, and a crotch portion located between the abdominal and dorsal portions, having a longitudinal direction corresponding to the direction extending from the abdominal portion through the crotch portion to the dorsal portion, and a transverse direction perpendicular to the longitudinal direction, The absorbent core has a two-layer structure including an upper absorbent core and a lower absorbent core located on the non-skin-facing side of the upper absorbent core. The absorbent core has a central bending guide portion in the lateral center, and side bending guide portions on each side of the central bending guide portion, and the central bending guide portion and the side bending guide portions each extend in the vertical direction. The central bending guide portion has an upper central through-hole that penetrates the upper absorbent core in the thickness direction but does not penetrate the lower absorbent core, and the side bending guide portion has a lower through-hole that penetrates the lower absorbent core in the thickness direction. A particulate water-absorbing polymer is disposed in the upper central through-hole and the lower through-hole. An absorbent article wherein the basis weight of the water-absorbing polymer in the upper central through-hole is higher than the basis weight of the water-absorbing polymer in the lower through-hole.
2. The absorbent article according to claim 1, wherein the absorbent core has a central region where the upper absorbent core and the lower absorbent core overlap, and a side region that is thinner than the central region.
3. The absorbent article according to claim 1 or 2, wherein in the crotch area, the lateral length of the upper central through-hole is shorter than the lateral length of the lower through-hole.
4. The absorbent article according to claim 1 or 2, wherein the side bending guide portion has less bending rigidity than the central bending guide portion.
5. The absorbent body has a core wrap sheet that covers the absorbent core, The central bending guide portion and the side bending guide portion have recessed portions formed in the core wrap sheet covering the skin-facing surface of the absorbent core, which are recessed toward the non-skin-facing surface. The absorbent article according to claim 1 or 2, wherein the depth of the recess in the side bending guide portion is greater than the depth of the recess in the central bending guide portion.
6. The absorbent core contains a fiber aggregate made of fibrous material such as defibrated pulp and a water-absorbing polymer. The absorbent article according to claim 1 or 2, wherein the side bending guide portion does not include the fiber aggregate.
7. The absorbent core has a central region where the upper absorbent core and the lower absorbent core overlap. The absorbent article according to claim 1 or 2, wherein in the central region, the basis weight of the central bending guide portion is lower than the basis weight of the portion other than the central bending guide portion.
8. The absorbent article according to claim 1 or 2, wherein the basis weight of the water-absorbing polymer in the upper central through-hole is 120% or more of the basis weight of the water-absorbing polymer in the lower through-hole.
9. The absorbent article according to claim 1 or 2, wherein, in the ventral side in the longitudinal direction, the central bending guide portion extends from the end position of the lateral bending guide portion and extends from the center of the absorbent body in the longitudinal direction toward the dorsal side.
10. The absorbent article according to claim 1 or 2, wherein, in the longitudinal direction on the back side, the side bending guide portion extends from the end position of the central bending guide portion and extends from the longitudinal center of the absorbent body toward the back side.
11. The absorbent article according to claim 1 or 2, wherein, in a plan view, the upper absorbent core and the side bending guide portion do not overlap.