Absorbent articles

Abstract

To provide an absorbent article that suppresses fluid leakage.SOLUTION: An absorbent article comprises: a liquid permeable top sheet; a liquid impermeable back sheet; an upper layer absorber arranged on the top sheet side between the back sheet and the top sheet; a lower layer absorber arranged on the back sheet side between the back sheet and the top sheet; a core wrap sheet wrapping the whole of the upper layer absorber and the lower layer absorber; an aperture that is formed to penetrate the upper layer absorber in a thickness direction, has width of 20 mm or more and 35 mm or less, and extends in a longer direction of the upper layer absorber; and a SAP layer that is arranged between the upper layer absorber and the lower layer absorber and includes a plurality of particles of a highly absorbent polymer, the basis weight of the highly absorbent polymer being 280 g / mor more and 400 g / mor less.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] There are known absorbent articles such as disposable diapers, absorbent pads (urine pads), sanitary napkins, etc. The absorbent articles are made of pulp or super absorbent polymer (SAP) and have an absorbent body that absorbs liquids such as urine and body fluids. Patent Document 1 describes an absorbent article that has an upper absorbent body and a lower absorbent body, and openings are formed in these absorbent bodies. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 114209 Summary of the Invention [Problem to be solved by the invention]

[0004] In absorbent articles, openings are sometimes formed in the absorbent body to enhance the diffusion of liquids. However, when openings are formed penetrating the upper and lower absorbent bodies, there is no absorbent body such as pulp or a highly absorbent polymer in the openings, and therefore the openings cannot absorb liquids such as urine, and there is a risk of the liquid leaking out.

[0005] Therefore, an object of the present invention is to provide an absorbent article that suppresses leakage of liquid. [Means for solving the problem]

[0006] In order to solve the above problems, in the present invention, a SAP layer is disposed between the upper absorbent body and the lower absorbent body.

[0007] In detail, the present invention relates to an absorbent article comprising: a liquid-permeable top sheet arranged on the skin-facing side; a liquid-impermeable back sheet arranged on the side opposite to the skin-facing side; an upper-layer absorbent body between the back sheet and the top sheet and arranged on the top sheet side; a lower-layer absorbent body between the back sheet and the top sheet and arranged on the back sheet side; a core wrap sheet wrapping the upper-layer absorbent body and the lower-layer absorbent body as a whole; an opening formed to penetrate the upper-layer absorbent body in the thickness direction and having a width of 20 mm or more and 35 mm or less and extending in the longitudinal direction of the upper-layer absorbent body; and a plurality of superabsorbent polymer particles arranged between the upper-layer absorbent body and the lower-layer absorbent body along the longitudinal direction of the opening, on both sides of the opening and within a range from 5 mm outside both ends of the opening to 10 mm from the ends of the upper-layer absorbent body, the superabsorbent polymer containing a plurality of particles, the basis weight of the superabsorbent polymer being 140 g / m. 2 More than 200g / m 2 and a SAP layer having a width of 40 mm or more, the longitudinal length of the SAP layer including the longitudinal length of the opening.

[0008] The above-mentioned absorbent article may further comprise a superabsorbent polymer contained in the upper absorbent body and the lower absorbent body, the superabsorbent polymer accounting for 45% or more in the upper absorbent body and 55% or less in the lower absorbent body, when the total basis weight ratio of the upper absorbent body and the lower absorbent body is 100%.

[0009] In the above-mentioned absorbent article, the basis weight of the superabsorbent polymer in the upper absorbent body is 50 g / m 2 More than 180g / m 2 The basis weight of the superabsorbent polymer in the lower absorbent body is 0 g / m or less. 2 More than 220g / m 2 It may be the following. Effect of the Invention

[0010] The above-mentioned absorbent article can suppress leakage of liquid. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view of an absorbent pad according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the absorbent pad according to the embodiment. [Diagram 3] FIG. 3 is a table showing the results of the absorbency test of the absorbent pad. [Figure 4] FIG. 4 is a table showing the results of the absorbency test of the absorbent pad. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present invention. The embodiment described below is an example of the present invention, and the technical scope of the present invention is not limited to the following aspect.

[0013] <Embodiment> FIG. 1 is a plan view of an absorbent pad (one example of an "absorbent article" in the present application) viewed from the skin-facing side. The absorbent pad 1 is used to absorb and retain liquids such as urine, and can be used alone or layered on the inside of a disposable diaper. The absorbent pad 1 is divided into a crotch region 5 covering the pubic area of ​​the wearer, a front body region 3 located on the wearer's abdominal side, and a rear body region 7 located on the wearer's back side, as viewed in the longitudinal direction. The direction perpendicular to the longitudinal direction is the width direction (short direction) of the absorbent pad 1. In plan view, the absorbent pad 1 has the narrowest width in the crotch region 5, and the crotch region 5 has a narrow gourd shape.

[0014] In the following, when the absorbent pad 1 is viewed in the longitudinal direction, the front body region 3 side is relatively referred to as the "front", "front side" or "forward", the rear body region 7 side is relatively referred to as the "rear", "rear side" or "rear", the left side relatively from the rear side to the front side is relatively referred to as the "left", "left side" or "left side", and the right side relatively from the rear side to the front side is relatively referred to as the "right", "right side" or "right side". The front-to-rear direction of the absorbent pad 1 is the longitudinal direction, and the left-to-right direction of the absorbent pad 1 is the width direction. The direction perpendicular to the front-to-rear and left-to-right directions is the thickness direction (height direction) of the absorbent pad 1.

[0015] As shown in Fig. 1, the absorbent pad 1 includes a top sheet 11 arranged on the skin-facing side when worn. The top sheet 11 is the portion (skin-facing side) that contacts the wearer's skin when the absorbent pad 1 is worn, and is made of a liquid-permeable material that allows liquids such as urine to pass through. Specifically, the top sheet 11 is made of woven fabric, nonwoven fabric, porous film, etc. Note that the nonwoven fabric may be made of thermoplastic resin fibers such as polypropylene, polyethylene, polyester, nylon, etc. that have been hydrophilized, or may be an air-through nonwoven fabric, point-bonded nonwoven fabric, spun-bonded nonwoven fabric, melt-blown nonwoven fabric, etc.

[0016] The absorbent pad 1 also includes a back sheet 13 disposed on the opposite side of the skin-facing surface when worn. The back sheet 13 is the surface (outer surface) opposite the skin-facing surface, and is made of a liquid-impermeable material that does not allow liquids such as urine to pass through. Specifically, a liquid-impermeable film made of polyethylene resin is used for the back sheet 13. Note that, in order to obtain breathability to prevent stuffiness when worn while maintaining liquid impermeability, it is preferable to use a microporous polyethylene film having a plurality of fine pores of 0.1 to 4 μm formed therein for the back sheet 13.

[0017] The top sheet 11 and the back sheet 13 are joined to each other at their respective peripheral edges. In addition, an upper layer absorbent body 15 and a lower layer absorbent body 17 that absorb liquids such as urine are disposed between the top sheet 11 and the back sheet 13. The upper layer absorbent body 15 is disposed on the top sheet 11 side (skin facing side), and the lower layer absorbent body 17 is disposed on the back sheet 13 side (non-skin facing side). In a plan view, the upper layer absorbent body 15 has a gourd shape that is roughly the same as that of the absorbent pad 1. The lower layer absorbent body 17 is disposed below the upper layer absorbent body 15 when viewed from the top sheet 11 side. In a plan view, the lower layer absorbent body 17 has a rectangular shape whose long side is the longitudinal direction of the absorbent pad 1. In a plan view, the upper layer absorbent body 15 is formed larger than the lower layer absorbent body 17. When liquids such as urine are excreted in the absorbent pad 1, the absorbent pad 1 is relatively large, and the upper layer absorbent body 15 disposed on the top sheet 11 side can rapidly absorb the urine.

[0018] The upper absorbent body 15 and the lower absorbent body 17 are made of fluff pulp obtained by crushing fibrous materials such as coniferous trees, super absorbent polymers (SAP), hydrophilic sheets, or combinations of these. SAP absorbs about 100 to 1000 times its own weight in liquid. For example, granular SAP having a diameter of about 0.1 to 0.5 mm before absorbing liquid is used.

[0019] The absorbent pad 1 also includes an opening 21 formed by penetrating the upper absorbent body 15 in the thickness direction. The opening 21 is formed so as to extend in the longitudinal direction of the upper absorbent body 15. The opening 21 is formed in the approximate center in the width direction of the upper absorbent body 15. In a plan view, the opening 21 has a rectangular shape. The front end of the opening 21 is located in the middle of the front body region 3, and the rear end of the opening 21 is located in the rear of the crotch region 5. The opening 21 also has a certain width w1. For example, the width w1 is 20 mm or more and 35 mm or less. The length of the opening 21 is formed to be 155 mm or more and 350 mm or less. In this case, the absorbent pad 1 is suitable for an adult urine pad.

[0020] The opening 21 may be formed in correspondence with the position where the wearer's urethral opening comes into contact (urethral opening contact position) so that urine excreted by the wearer can easily flow in. The urethral opening contact position is determined to be 60% of the longitudinal length of the upper absorbent body 15 forward from the rear end of the upper absorbent body 15. For example, when the longitudinal length of the upper absorbent body 15 is 500 mm, the urethral opening contact position is determined to be 300 mm forward from the rear end of the upper absorbent body 15. In addition, when an R-cut cut into an arc shape is formed at both left and right ends of the crotch region 5, the longitudinal length of the R-cut forming portion is within 30 mm, and the narrowest portion of the width of the upper absorbent body 15 is the portion where the R-cut is formed, the intersection of a straight line connecting the left and right ends of the narrowest portion and a straight line passing through the center of the width of the upper absorbent body 15 may be determined to be the urethral opening contact position.

[0021] In addition, the opening 21 may be formed in a polygonal shape or an elliptical shape instead of a rectangular shape in a plan view. In addition, both front and rear ends of the opening 21 may be formed in an arc shape.

[0022] Liquids such as urine excreted by the wearer are spread along the openings 21. Furthermore, liquids such as urine excreted on the upper absorbent body 15 can be guided to the lower absorbent body 17 through the openings 21. In this way, the absorbent pad 1 according to this embodiment can absorb and retain liquids by both the upper absorbent body 15 and the lower absorbent body 17.

[0023] The absorbent pad 1 also has SAP layers 23L, 23R disposed between the upper absorbent body 15 and the lower absorbent body 17. The SAP layers 23L, 23R are formed by gathering together a plurality of particles of superabsorbent polymer (SAP). The SAP layers 23L, 23R contain a plurality of SAP particles and are capable of absorbing and retaining liquid introduced between the upper absorbent body 15 and the lower absorbent body 17. As shown in FIG. 1, the SAP layer 23L is disposed to the left of the opening 21, and the SAP layer 23R is disposed to the right of the opening 21. 1, the SAP layer 23R is disposed to the right of the absorbent pad 1. In this way, the SAP layers 23L, 23R are disposed on both sides of the opening 21 along the longitudinal direction of the opening 21. In addition, the SAP layers 23L, 23R are formed in a rectangular shape in plan view. Note that the SAP layers 23L, 23R may be formed in a polygonal shape or an elliptical shape in plan view instead of a rectangular shape. By providing the absorbent pad 1 with the SAP layers, the overall amount of liquid absorbed can be increased.

[0024] The SAP layer 23L is disposed from w2 mm outside the left end of the opening 21 to w3 mm inside the left end of the upper absorbent body 15. Similarly, the SAP layer 23R is disposed from w2 mm outside the right end of the opening 21 to w3 mm inside the right end of the upper absorbent body 15. In this way, the SAP layers 23L, 23R are disposed from w2 mm outside both ends of the opening 21 to w3 mm inside the widthwise ends of the upper absorbent body 15. w2 mm is, for example, 5 mm, and w3 mm is, for example, 10 mm. Furthermore, the SAP layers 23L, 23R are longer than the opening 21, and the longitudinal length of the opening 21 is included in the longitudinal length of the SAP layers 23L, 23R.

[0025] In this embodiment, the SAP layers 23L, 23R are arranged on both sides of the opening 21 along the longitudinal direction of the opening 21, and within a range of 5 mm outside both ends of the opening 21 and 10 mm from the end of the upper absorbent body 15, and the width of the SAP layers 23L, 23R is 40 mm or more.

[0026] Thus, the absorbent pad 1 according to this embodiment includes the upper absorbent body 15, the lower absorbent body 17, the opening 21, and the SAP layers 23L and 23R. The longitudinal directions of the upper absorbent body 15, the lower absorbent body 17, the opening 21, and the SAP layers 23L and 23R are aligned. Furthermore, the opening 21 and the SAP layers 23L and 23R are disposed approximately parallel to each other.

[0027] Furthermore, the absorbent pad 1 has three-dimensional gathers (not shown) arranged along the left and right ends of the lower absorbent body 17 when viewed from the skin-facing surface side. The three-dimensional gathers are joined to the top sheet 11 and suppress side leakage of liquid.

[0028] Fig. 2 is a cross-sectional view of the absorbent pad 1 shown in Fig. 1 taken along line AA. In Fig. 2, in order to make each component of the absorbent pad 1 easier to understand, gaps are provided between each component, but in reality, there are almost no gaps between each component.

[0029] As shown in FIG. 2, the upper absorbent body 15 and the lower absorbent body 17 are entirely wrapped by the core wrap sheets 31 and 33. The core wrap sheets 31 and 33 are provided to diffuse the liquid that has permeated the top sheet 11 throughout the upper absorbent body 15 and the lower absorbent body 17. The core wrap sheet 31 is disposed between the top sheet 11 and the upper absorbent body 15, and covers the upper absorbent body 15 from the top sheet 11 side. The core wrap sheet 33 covers the back sheet 13 side surface of the lower absorbent body 17, the sides of the upper absorbent body 15 and the lower absorbent body 17, and a part of the top sheet 11 side surface of the upper absorbent body 15, and is joined to the core wrap sheet 31 on the top sheet 11 side. In this way, the core wrap sheets 31 and 33 are joined to each other to be integrated, and entirely wrap the upper absorbent body 15 and the lower absorbent body 17. For example, thin paper such as tissue paper, nonwoven fabric, etc. are used for the core wrap sheets 31, 33. The core wrap sheets 31, 33 may be integrally formed.

[0030] The SAP layers 23L, 23R are formed by scattering SAP particles on the lower absorbent body 17. The SAP layers 23L, 23R are sandwiched between the upper absorbent body 15 and the lower absorbent body 17. Therefore, even if the absorbent pad 1 moves due to the wearer's movements, It is possible to prevent the SAP particles contained in the SAP layers 23L, 23R from migrating below the opening 21 or from falling outside the lower absorbent body 17.

[0031] As described above, the absorbent pad 1 according to this embodiment has a structure in which, viewed in the thickness direction from the skin-facing surface side, the top sheet 11, the core wrap sheet 31, a part of the core wrap sheet 33, the upper absorbent body 15, the SAP layers 23L and 23R, the lower absorbent body 17, a part of the core wrap sheet 33, and the back sheet 13 are laminated in this order. In addition, the peripheral edges of the top sheet 11 and the back sheet 13 are joined to each other, so that the core wrap sheets 31 and 33, the upper absorbent body 15, the SAP layers 23L and 23R, and the lower absorbent body 17 are surrounded and sealed by the top sheet 11 and the back sheet 13.

[0032] Incidentally, in the absorbent pad described in the above Patent Document 1, a through-type opening is formed penetrating the upper absorbent body and the lower absorbent body in the thickness direction. When the through-type opening is viewed in the thickness direction, there is no absorbent body such as fluff pulp or SAP, so that the opening cannot absorb liquid such as urine. On the other hand, in the absorbent pad 1 according to the present embodiment, an opening 21 is formed in the upper absorbent body 15, and no opening is formed in the lower absorbent body 17. Therefore, in the absorbent pad 1 according to the present embodiment, a part of the lower absorbent body 17 faces the opening end below the opening 21 (on the lower absorbent body 17 side) when viewed in the thickness direction, so that the lower absorbent body 17 can absorb liquid that flows into the opening 21. In addition, if the dimensions of each component of the absorbent pad described in the above Patent Document 1 and the absorbent pad 1 according to the present embodiment are the same, the absorbent pad described in the above Patent Document 1 has a smaller volume of absorbent body by the volume of the opening formed in the lower absorbent body compared to the absorbent pad 1 according to the present embodiment. For this reason, when the absorbent pad described in Patent Document 1 is worn and the amount of urination is large, there is a risk that the absorption capacity of the lower absorbent body will be insufficient, resulting in urine leakage. However, in the absorbent pad 1 according to this embodiment, since no openings are formed in the lower absorbent body 17, the volume of the lower absorbent body 17 is not reduced, and urine leakage can be suppressed without causing an insufficient absorption capacity of the lower absorbent body 17 even when the amount of urination is large.

[0033] <Example 1> Next, the absorbent pad 1 according to Example 1 of this embodiment will be described. The absorbent pad 1 according to this example is characterized by the basis weight ratio of SAP in the upper absorbent body 15 and the lower absorbent body 17.

[0034] In the absorbent pad 1 according to this embodiment, for example, fluff pulp is used for the upper absorbent body 15 and the lower absorbent body 17. The upper absorbent body 15 contains SAP. The lower absorbent body 17 may contain SAP. If the total basis weight ratio of SAP in the upper absorbent body 15 and the lower absorbent body 17 is 100%, the basis weight ratio of SAP in the upper absorbent body 15 is 45% or more and the basis weight ratio of SAP in the lower absorbent body 17 is 55% or less. If the lower absorbent body 17 does not contain SAP, the basis weight ratio of SAP in the upper absorbent body 15 is 100% and the basis weight ratio of SAP in the lower absorbent body 17 is 0%.

[0035] The SAP weight in the upper absorbent body 15 is 50 g / m 2 More than 180g / m 2 The basis weight of the SAP in the lower absorbent body 17 is 0 g / m 2 More than 220g / m 2 The lower limit of the basis weight of the SAP in the lower absorbent body 17 is 0 g / m 2 and the basis weight is 0g / m 2 If so, SAP is not included.

[0036] In the absorbent pad 1 according to this embodiment, the upper absorbent body 15 containing SAP quickly absorbs liquids such as urine, thereby preventing the top sheet 11 from absorbing liquids and preventing liquids from pooling on the surface of the top sheet 11, thereby preventing the wearer from feeling uncomfortable. In addition, the lower absorbent body 17 absorbs liquids that the upper absorbent body 15 was not able to absorb and liquids that are released through the openings 21. The absorbent pad 1 according to this embodiment absorbs and retains liquid with the upper absorbent body 15 and the lower absorbent body 17, thereby preventing leakage of liquid.

[0037] In general, when an upper absorbent body and a lower absorbent body are provided, it is considered to increase the absorption capacity of the lower absorbent body to suppress liquid leakage to the back sheet side. In order to increase the absorption capacity of the absorbent body, for example, the basis weight ratio or basis weight of SAP in the lower absorbent body is increased. However, when an opening is formed in the upper absorbent body and an opening is not formed in the lower absorbent body, if the basis weight ratio of SAP in the lower absorbent body is increased more than necessary, the lower absorbent body may absorb a large amount of liquid and swell too much, which may block the opening. For example, if the lower absorbent body absorbs urine and swells to block the opening during the first urination, urine cannot be diffused through the opening during the second and subsequent urinations, which may cause urine leakage. On the other hand, in the absorbent pad 1 according to this embodiment, when the total basis weight ratio of SAP in the upper absorbent body 15 and the lower absorbent body 17 is 100%, the basis weight ratio is 45% or more in the upper absorbent body 15 and 55% or less in the lower absorbent body 17. This prevents the lower absorbent body 17 from swelling to the extent that it blocks the opening 21 when absorbing liquid, thereby preventing blocking of the opening 21. The absorbent pad 1 according to this embodiment prevents the lower absorbent body 17 from blocking the opening 21 when absorbing liquid such as urine, and diffuses urine through the opening during second and subsequent urinations, thereby suppressing urine leakage.

[0038] Next, a urine injection test (hereinafter referred to as "the test") for an absorbent pad will be described. In this test, a suitable range of the basis weight ratio of SAP in the upper absorbent body 15 and the lower absorbent body 17 that can suppress liquid leakage is derived. If the absorbent pad is provided with SAP layers 23L, 23R, the absorption amount of the SAP layers 23L, 23R will affect the test results, making it impossible to derive a suitable range of the basis weight ratio of the SAP. For this reason, an absorbent pad not provided with the SAP layers 23L, 23R was created and this test was carried out.

[0039] The test materials used in this test were a test plate (16cm x 16cm, made of iron, 10mm thick), artificial urine, and filter paper (80mm x 8mm). The test plate had a circular hole (diameter 40mm) in the center.

[0040] Next, the absorbent pad is spread out without any wrinkles and fixed in place using a packing tape or a hook tape, with the rear body region facing the worker.

[0041] The test plate is placed on the absorbent pad so that the center of the hole in the test plate is located at the center of the longitudinal direction of the opening of the absorbent pad. Next, 150 ml of artificial urine is prepared. The artificial urine was prepared by dissolving 20 g of urea, 8 g of sodium chloride, 0.8 g of magnesium sulfate heptahydrate, and 0.3 g of calcium chloride dihydrate in 1000 mL of distilled water. 150 ml of the prepared artificial urine is poured into the hole in the test plate. When the absorbent pad has absorbed all of the artificial urine, the test plate is removed from the absorbent pad. The absorbent pad has absorbed all of the artificial urine when all of the artificial urine poured into the absorbent pad has disappeared from the top sheet. The time from the start of the injection of the artificial urine to the time when the artificial urine is completely absorbed was evaluated as the absorption rate (seconds). 11 minutes after the first injection of artificial urine into the absorbent pad, the test plate is placed on the absorbent pad in the same manner as above, and 11 minutes after the first injection of artificial urine, 140 ml of artificial urine is injected into the absorbent pad again in the same manner as above. This process is repeated one more time. In total, 430 ml of artificial urine is injected into the absorbent pad.

[0042] Figure 3 is a table showing the results of this test. In this test, the SAP basis weight ratio in the upper and lower absorbent layers was changed in 5% increments between 0 and 100% (21 pieces), and the width of the opening was changed in 5 mm increments between 15 mm and 40 mm (6 pieces), to create a total of 121 absorbent pads. Successful.

[0043] The column "Leakage Suppression" in the table of FIG. 3 indicates whether the absorbent pad was able to suppress leakage of liquid. "◎" and "〇" in the column indicate results in which leakage was suppressed. More specifically, "◎" in the column indicates results in which the lower absorbent body did not fill the opening at all, and leakage was suppressed without a decrease in absorption rate. "〇" in the column indicates results in which the lower absorbent body hardly filled the opening, and leakage was suppressed without a decrease in absorption rate. Also, "△", "×1", "×2", and "×3" in the column indicate results in which leakage could not be suppressed. More specifically, "×1" in the column indicates results in which the opening was filled due to the swelling of the lower absorbent body, causing a decrease in absorption rate, and leakage could not be suppressed. "×2" in the column indicates results in which the opening was not filled, but the width of the opening was too narrow, so it took time for the artificial urine to diffuse through the opening, and the artificial urine was absorbed before it was completely diffused, and the opening could not perform its function of diffusing the artificial urine, causing the absorption rate to decrease and leakage could not be suppressed. An "x3" in the relevant column indicates that the opening was not filled, but the opening was too wide, so the artificial urine was absorbed before it could completely diffuse in the longitudinal direction of the opening, and therefore the opening was unable to perform its function of diffusing the artificial urine and therefore leakage could not be suppressed.

[0044] As can be seen from the table in Figure 3, when the opening width is 20 mm, it is preferable that the SAP basis weight ratio in the upper absorbent body is greater than 30% and the SAP basis weight ratio in the lower absorbent body is greater than 70%, it is even more preferable that the SAP basis weight ratio in the upper absorbent body is greater than 35% and the SAP basis weight ratio in the lower absorbent body is greater than 65%, and leakage can be suppressed by setting the SAP basis weight ratio in the upper absorbent body to 45% or more and the SAP basis weight ratio in the lower absorbent body to 55% or more. Similarly, when the opening width is 25 mm, it is preferable that the SAP basis weight ratio in the upper absorbent body is greater than 25% and the SAP basis weight ratio in the lower absorbent body is greater than 75%, it is even more preferable that the SAP basis weight ratio in the upper absorbent body is greater than 30% and the SAP basis weight ratio in the lower absorbent body is greater than 70%, it is even more preferable that the SAP basis weight ratio in the upper absorbent body is greater than 35% and the SAP basis weight ratio in the lower absorbent body is greater than 65%, and leakage can be suppressed by setting the SAP basis weight ratio in the upper absorbent body to 45% or more and the SAP basis weight ratio in the lower absorbent body to 55% or more. Similarly, when the opening width is 30mm or 35mm, it is preferable that the SAP basis weight ratio in the upper absorbent body is greater than 20% and the SAP basis weight ratio in the lower absorbent body is greater than 80%, it is even more preferable that the SAP basis weight ratio in the upper absorbent body is greater than 25% and the SAP basis weight ratio in the lower absorbent body is greater than 75%, it is even more preferable that the SAP basis weight ratio in the upper absorbent body is greater than 30% and the SAP basis weight ratio in the lower absorbent body is greater than 70%, it is even more preferable that the SAP basis weight ratio in the upper absorbent body is greater than 35% and the SAP basis weight ratio in the lower absorbent body is greater than 65%, and leakage can be suppressed by setting the SAP basis weight ratio in the upper absorbent body to 45% or more and the SAP basis weight ratio in the lower absorbent body to 55% or more.

[0045] Thus, when the opening width is 20-35mm, it is preferable that the SAP weight ratio in the upper absorbent body is greater than 30% and the SAP weight ratio in the lower absorbent body is greater than 70%, it is even more preferable that the SAP weight ratio in the upper absorbent body is greater than 35% and the SAP weight ratio in the lower absorbent body is greater than 65%, and leakage could be suppressed by setting the SAP weight ratio in the upper absorbent body to 45% or more and the SAP weight ratio in the lower absorbent body to 55% or more. Note that when the SAP weight ratio in the upper absorbent body is 95% or 100% and the SAP weight ratio in the lower absorbent body is 5% or 0%, leakage was suppressed most effectively, as shown by the leakage suppression result of "◎".

[0046] On the other hand, when the opening width was 15 mm or 40 mm, leakage could not be suppressed. When the opening width was 15 mm, and the SAP basis ratio in the upper absorbent was 45% or more and the SAP basis ratio in the lower absorbent was 55% or less, the leakage suppression result was shown by "x2", as the opening width was too narrow and it took a long time for the artificial urine to diffuse through the opening, and the artificial urine was absorbed before it was completely diffused, so the opening could not perform its function of diffusing the artificial urine, and the absorption rate decreased, so leakage could not be suppressed. When the opening width was 40 mm, and the SAP basis ratio in the upper absorbent was 30% or more and the SAP basis ratio in the lower absorbent was 70% or less, the leakage suppression result was shown by "x3", as the opening was not filled, but the opening width was too wide and the artificial urine was absorbed before it was completely diffused in the longitudinal direction of the opening, so the opening could not perform its function of diffusing the artificial urine, so leakage could not be suppressed. For this reason, the width of the opening 21 is preferably greater than 15 mm and less than 40 mm, and more preferably, is 20 mm or more and 35 mm or less.

[0047] In this way, as shown in FIG. 3, when the SAP basis weight ratio was 45% or more in the upper absorbent body 15 and 55% or less in the lower absorbent body 17, leakage could be suppressed.

[0048] In addition, since SAP has the function of retaining liquid in the absorbent body, if the basis weight of SAP in the upper absorbent body is too small, the upper absorbent body will not be able to retain all the liquid it has absorbed and will return back to its original state, whereas if the basis weight of SAP in the upper absorbent body is too large, gel blocks will form when absorbing liquid, slowing down the absorption rate. Furthermore, if the basis weight of SAP in the lower absorbent body is too large, the lower absorbent body will absorb too much liquid and swell, filling up the openings. For this reason, the basis weight of SAP in the upper absorbent body is set at 50 g / m 2 More than 180g / m 2 The SAP weight in the lower absorbent body is within the range below 0 g / m 2 More than 220g / m 2 Even within this range of basis weight, leakage can be suppressed as long as the SAP basis weight ratio is within the above range. In the experimental example shown in Figure 3, leakage was suppressed when the SAP basis weight in the upper absorbent body was 90 g / m 2 ~170g / m 2 The SAP weight of the lower absorbent body is 0 g / m 2 ~120g / m 2 It was.

[0049] The absorbent pad 1 according to this embodiment is provided with SAP, which is included in the upper absorbent body 15 and the lower absorbent body 17, and which accounts for 45% or more in the upper absorbent body 15 and 55% or less in the lower absorbent body 17, assuming that the total basis weight ratio of the upper absorbent body 15 and the lower absorbent body 17 is 100%. In the absorbent pad 1 according to this embodiment, the basis weight of the SAP in the upper absorbent body 15 is 50 g / m 2 More than 180g / m 2 The basis weight of the SAP in the lower absorbent body 17 is 0 g / m 2 More than 220g / m 2 The absorbent pad 1 according to this embodiment can diffuse liquid through the openings 21, thereby preventing liquid from leaking.

[0050] In the case of the result of "◎", the absorption speed in the test in which artificial urine was injected three times was 20 seconds or less. In the case of the result of "◯", the absorption speed in the test in which artificial urine was injected three times was 21 seconds or more and 25 seconds or less. In the case of the result of "△", the absorption speed in the test in which artificial urine was injected three times was 26 seconds or more and 59 seconds or less. In the result of "×1", the absorption speed in the test in which artificial urine was injected three times was 60 seconds or more. In the results of "×2" and "×3", the absorption speed was not evaluated because the opening was not able to diffuse the artificial urine. If the absorption speed is 26 seconds or more, the unabsorbed artificial urine will accumulate on the top sheet, and side leakage may occur from the gap between the three-dimensional gathers and the skin, which is not preferable. According to the absorbent pad 1 of this embodiment, the liquid leakage can be suppressed without decreasing the liquid absorption speed.

[0051] <Example 2> Next, a description will be given of an absorbent pad 1 according to Example 2 of this embodiment. The absorbent pad 1 according to this example is characterized by the basis weight of the SAP in the SAP layers 23L, 23R.

[0052] In the absorbent pad 1 according to this embodiment, the basis weight of each of the SAP layers 23L and 23R is, for example, 140 to 200 g / m 2 The length (length in the front-rear direction) of each of the SAP layers 23L, 23R is 470 to 555 mm, the width of each of the SAP layers 23L, 23R is 40 mm or more, preferably 40 to 45 mm, and the area of ​​each of the SAP layers 23L, 23R is 0.018 to 0.025 m 2 The amount of SAP sprayed in each of the SAP layers 23L and 23R is 6 to 10 g.

[0053] The absorbent pad 1 according to this embodiment is capable of directing a portion of liquid such as urine excreted by the wearer to below the upper absorbent body 15 via the openings 21 and absorbing it in the SAP layers 23L, 23R. As a result, even when a large amount of liquid such as urine is excreted at once, the absorbent pad 1 is able to absorb the liquid in the SAP layers 23L, 23R, thereby preventing leakage of the liquid.

[0054] Furthermore, when each SAP particle absorbs liquid, the SAP layers 23L, 23R swell overall and become thicker. As the thickness of the SAP layers 23L, 23R arranged between the upper absorbent body 15 and the lower absorbent body 17 increases, the SAP layers 23L, 23R lift the upper absorbent body 15, and the height of the region 24 between the SAP layers 23L, 23R (region below the opening 21) also increases, and the opening end of the opening 21 on the lower absorbent body 17 side can be extended by the thickness of the SAP layer to increase the height of the opening 21. This prevents the lower absorbent body 17 from blocking the opening 21 even if the lower absorbent body absorbs urine and swells, and by diffusing the urine through the opening 21, leakage of liquids such as urine can be suppressed.

[0055] Furthermore, in the absorbent pad 1 according to this embodiment, the longitudinal length of the SAP layers 23L, 23R is included in the longitudinal length of the opening 21. This allows the SAP layers 23L, 23R to absorb liquid and increase in thickness, thereby increasing the overall height of the opening 21, thereby preventing a portion of the opening 21 from being blocked and diffusing urine through the opening 21, thereby suppressing leakage of liquids such as urine.

[0056] Next, a test similar to that in Example 1 was carried out. Fig. 4 is a table showing the results of a urine injection test of the absorbent pad. In this test, the SAP basis weight (g / m 2 ) between 0 and 240 (g / m 2 )% increments (13 pads), and the width of the opening was changed in 5 mm increments from 15 mm to 40 mm (6 pads), creating a total of 78 absorbent pads.

[0057] The column "Leakage Suppression" in the table of FIG. 4 indicates whether the absorbent pad was able to suppress liquid leakage. In this column, "◎" and "◯" indicate results in which leakage was suppressed. More specifically, The "◎" in the relevant column indicates the area between the SAP layers on both sides due to the expansion of the SAP layer (Figure 2The "○" in the corresponding column indicates that the SAP layer swells slightly, increasing the height of the area between the SAP layers on both sides, and the lower absorbent body does not fill the opening at all, so leakage is suppressed without decreasing the absorption rate.

[0058] In the relevant column, "△", "×1", "×2", "×3", and "×4" indicate results in which leakage could not be suppressed. More specifically, "△" indicates that the SAP layer did not expand much, so the height of the area between the SAP layers on both sides did not increase, and the lower absorbent layer filled the opening a little, resulting in a slower absorption rate. The result shows that the SAP layer did not expand at all, so the height of the area between the SAP layers on both sides did not increase, and the lower absorbent filled the opening, so the absorption rate decreased and leakage could not be suppressed. The result shows that the opening was not filled, but the width of the opening was too narrow, so it took time for the artificial urine to diffuse through the opening, and the artificial urine was absorbed before it was completely diffused, so the leakage could not be suppressed due to the decreased absorption rate. The result shows that the opening was not filled, but the width of the opening was too wide, so the artificial urine was absorbed before it was completely diffused in the longitudinal direction of the opening, so the opening could not perform its function of diffusing the artificial urine, and leakage could not be suppressed. The result shows that the SAP basis weight in the SAP layer was too large (too many SAP particles), so the expanded SAP layer overflowed into the opening, and the opening was filled with SAP, so the absorption rate decreased and leakage could not be suppressed.

[0059] As can be seen from the table in Figure 4, when the opening width is 15 mm, the basis weight of the SAP in the SAP layer is 80 g / m 2 It is preferable to set it higher, and 100 g / m 2 Larger is more preferable, 120 g / m 2 Even larger values ​​are more preferable, such as 140 g / m 2Similarly, when the opening width is 20 mm, the basis weight of the SAP in the SAP layer is 60 g / m or more. 2 It is preferable to use a larger value, 80 g / m 2 A larger value is more preferable, and 100 g / m 2 It is even more preferable to increase it to 120 g / m 2 Even larger values ​​are more preferable, such as 140 g / m 2 Similarly, when the opening width is 25 mm or 30 mm, the basis weight of the SAP in the SAP layer is 40 g / m or more. 2 It is preferable to use a larger value, 60 g / m 2 It is even more preferable to increase it to 80 g / m 2 It is even more preferable to increase it to 100 g / m 2 It is even more preferable to increase it to 120 g / m 2 Even larger values ​​are more preferable, such as 140 g / m 2 Similarly, when the opening width is 35 mm, the SAP weight in the SAP layer is 20 g / m or more. 2 It is preferable to set it larger, 40 g / m 2 It is even more preferable to increase it to 60 g / m 2 It is even more preferable to increase it to 80 g / m 2 It is even more preferable to increase it to 100 g / m 2 It is even more preferable to increase it to 120 g / m 2 Even larger values ​​are more preferable, such as 140 g / m 2 By setting the above, leakage could be suppressed.

[0060] Thus, when the opening width is 15 to 35 mm, the basis weight of the SAP in the SAP layer is 80 g / m 2 It is preferable to set it higher, and 100 g / m 2 Larger is more preferable, 120 g / m 2 Even larger values ​​are more preferable, such as 140 g / m 2More than 200g / m 2 The leakage was suppressed when the SAP basis weight was 200 g / m or less. 2 As indicated by "◎" in the column, the SAP basis weight is 200g / m 2 In the case where the leakage was most suppressed,

[0061] On the other hand, when the opening width was 40 mm, leakage could not be suppressed regardless of the SAP basis weight in the SAP layer. This is because, as shown by the fact that most results when the opening width was 40 mm were "x3", the opening width was too wide and the artificial urine was absorbed before it could be fully diffused in the longitudinal direction of the opening, so that the opening could not perform its function of diffusing the artificial urine and leakage could not be suppressed. For this reason, the width of the opening 21 is preferably less than 40 mm, and preferably 35 mm or less.

[0062] As shown in FIG. 4, the basis weight of the SAP in the SAP layer is set to 140 to 200 (g / m 2 ), leakage could be suppressed. The absorbent pad 1 according to this embodiment has a basis weight of SAP in the SAP layer of 140 g / m 2 More than 200g / m 2 The absorbent pad 1 according to this embodiment can diffuse liquid through the openings 21, thereby preventing liquid from leaking.

[0063] In the case of the result of "◎", the absorption speed in the test in which artificial urine was injected three times was 20 seconds or less. In the case of the result of "◯", the absorption speed in the test in which artificial urine was injected three times was 21 seconds or more and 25 seconds or less. In the case of the result of "△", the absorption speed in the test in which artificial urine was injected three times was 26 seconds or more and 59 seconds or less. In the result of "×1", the absorption speed in the test in which artificial urine was injected three times was 60 seconds or more. In the results of "×2", "×3", and "×4", the absorption speed was not evaluated. If the absorption speed is 26 seconds or more, the unabsorbed artificial urine may accumulate on the top sheet, causing side leakage from the gap between the three-dimensional gathers and the skin, which is not preferable. According to the absorbent pad 1 of this embodiment, the liquid leakage can be suppressed without decreasing the liquid absorption speed.

[0064] In the above embodiment and examples, the absorbent pad 1 is exemplified, but the above configuration can be applied to other types of absorbent articles. Examples of absorbent articles to which the above configuration can be applied include various types of absorbent articles with gathers, such as pants-type disposable diapers, tape-type disposable diapers, urine pads, and light incontinence pads, as well as flat absorbent articles without gathers. [Explanation of symbols]

[0065] 1·Absorbent pad:3·Front body area:5·Inseam area:7·Back body area:11·Top sheet:13·Back sheet:15·Upper absorbent layer:17·Lower absorbent layer:21·Opening:23L·SAP layer:23R·SAP layer:31·Core wrap sheet:33·Core wrap sheet

Claims

[Claim 1] A liquid-permeable top sheet disposed on the skin-facing side; A liquid-impermeable back sheet disposed on the opposite side of the skin-facing surface; an upper absorbent body disposed between the back sheet and the top sheet on the side of the top sheet; a lower absorbent body disposed between the back sheet and the top sheet on the back sheet side; a core wrap sheet that wraps the entire upper absorbent body and the entire lower absorbent body; an opening formed through the upper absorbent body in a thickness direction, having a width of 15 mm or more and 35 mm or less, and extending in a longitudinal direction of the upper absorbent body; a plurality of superabsorbent polymer particles are disposed between the upper absorbent body and the lower absorbent body, on both sides of the opening along the longitudinal direction of the opening, and within a range of 5 mm outside both ends of the opening and 10 mm from the end of the upper absorbent body; the superabsorbent polymer particles have a basis weight of 140 g / m ２ Above, 200g / m ２ a SAP layer, Equipped with The lower absorbent body does not have an opening that overlaps with the opening of the upper absorbent body, the width of the SAP layer is greater than or equal to 40 mm and less than or equal to 45 mm; a longitudinal length of the SAP layer includes a longitudinal length of the opening; Absorbent articles.

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