Absorbent article

Abstract

To provide an absorbent article capable of suppressing occurrence of ammonia.SOLUTION: An absorbent article has a length along a longitudinal direction corresponding to a cross direction of a wearer, a length along a width direction orthogonal to the longitudinal direction. The absorbent article comprises: an absorber which has an absorbent core obtained by laminating in the order from a non-skin surface side, a flow guide layer, a lower SAP layer where basis weight of SAP being a high absorbent polymer is less than 180 g / m2 and liquid absorption amount is 370 g or less, a base layer, an upper SAP layer, and a diffusion layer, and a water permeable sheet covering non-skin surface and skin surface sides of the absorbent core; a skin surface sheet which is arranged closer to the skin surface side relative to the absorber, has water permeability and includes an acidification agent; and a non-skin surface sheet which is arranged closer to the non-skin surface side relative to the absorber and has non-water permeability.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] 2. Description of the Related Art Absorbent articles such as diapers are known (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-19728 Summary of the Invention [Problem to be solved by the invention]

[0004] The urine excreted by the wearer contains urea. When urea is broken down by enzymes, ammonia is produced. Ammonia can cause odor and can also cause skin problems for the wearer.

[0005] An object of the present invention is to provide an absorbent article capable of suppressing the generation of ammonia. [Means for solving the problem]

[0006] An absorbent article according to one aspect of the present invention comprises: A length along a longitudinal direction corresponding to the front-to-back direction of the wearer; A length along a width direction perpendicular to the longitudinal direction; From the non-skin side, the material is a flow-guiding layer, a highly absorbent polymer called SAP with a basis weight of 180 g / m 2 an absorbent body having an absorbent core in which a lower SAP layer, a base layer, an upper SAP layer, and a diffusion layer are laminated, the lower SAP layer having a thickness of less than 100 mm and a liquid absorption capacity of 370 g or less, and a water-permeable sheet covering the non-skin-facing side and the skin-facing side of the absorbent core; a skin-facing sheet that is disposed on the skin-facing side of the absorbent body, has water permeability, and contains an acidifying agent; a non-skin-facing sheet that is disposed on the non-skin-facing side of the absorbent body and has water impermeability; Equipped with. Effect of the Invention

[0007] According to the present invention, it is possible to suppress the generation of ammonia. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a diaper according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the diaper according to the embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of the diaper according to the embodiment taken along the width direction at the center in the longitudinal direction. [Figure 4] FIG. 4 is a plan view of the diaper according to the embodiment in a stretched state. [Diagram 5] FIG. 5 is a cross-sectional view of an absorbent core of a diaper according to an embodiment. [Figure 6] FIG. 6 is a cross-sectional view of the diaper according to the embodiment, taken along the longitudinal direction at the center in the width direction. [Figure 7] FIG. 7 is a table (part 1) showing the results of a moisture absorption test of diapers. [Figure 8] FIG. 8 is a table (part 2) showing the results of the moisture absorption test of diapers. [Figure 9] FIG. 9 is a table (part 3) showing the results of the moisture absorption test of diapers. [Figure 10] FIG. 10 is a diagram showing a manufacturing apparatus for manufacturing the diaper according to the embodiment. [Figure 11] FIG. 11 is a diagram showing an outline of the SAP fixation rate test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, absorbent articles according to embodiments of the present invention will be described with reference to the drawings. Note that the configurations of the following embodiments are merely examples, and the present invention is not limited to the configurations of these embodiments.

[0010] <Embodiment> In this embodiment, the longitudinal direction of a tape-type disposable diaper (an example of an "absorbent article" in the present application, hereinafter simply referred to as a "diaper") is the direction connecting the front body arranged opposite the wearer's abdomen and the rear body arranged opposite the wearer's back. Between the front body (one side in the longitudinal direction) and the rear body (the other side in the longitudinal direction) (the center in the longitudinal direction), a crotch portion arranged under the wearer's crotch (opposed to the crotch). In addition, when the diaper is worn by a wearer (hereinafter abbreviated as "worn state"), the side facing the wearer's skin (the inner side when worn) is the skin-facing side, and the opposite side to the skin-facing side (the outer side when worn) is the non-skin-facing side. Furthermore, the direction connecting the skin-facing side and the non-skin-facing side is the thickness direction, and the direction perpendicular to both the longitudinal direction and the thickness direction is the width direction. In addition, the view from the thickness direction is the planar view. Additionally, the front, back, left and right of the diaper 1 refer to the directions that correspond to the front, back, left and right of the wearer when the diaper 1 is worn by the wearer. For example, the left and right direction in this application refers to the directions that correspond to the left and right of the wearer when the diaper 1 is worn by the wearer, and the front and back direction in this application refers to the directions that correspond to the front and back of the wearer when the diaper 1 is worn by the wearer.

[0011] FIG. 1 is a perspective view of a diaper according to the present embodiment. The diaper 1 has a length along the longitudinal direction and a length along the width direction perpendicular to the longitudinal direction. The diaper 1 has a crotch region 1B, which is a region corresponding to the crotch of the wearer covering the pubic area of ​​the wearer when worn, a front body region 1F, which is located in front of the crotch region 1B and corresponds to the front body of the wearer, and a back body region 1R, which is located behind the crotch region 1B and corresponds to the back body of the wearer. Tapes 2L and 2R that can be attached to a front patch 2F provided on the non-wearer side surface of the front body region 1F are provided on both left and right edges of the back body region 1R. When the tapes 2L and 2R are attached to the front patch 2F with the front body region 1F arranged on the wearer's abdomen and the back body region 1R arranged on the wearer's back, the diaper 1 is fixed to the wearer's body in a state of surrounding the wearer's waist circumference and thighs. Since the diaper 1 is fixed to the wearer's body in this manner, the wearer can stand and walk around while wearing the diaper 1.

[0012] In the diaper 1, an absorbent capable of absorbing and retaining liquid is mainly arranged in the crotch region 1B. In addition, in order to prevent the formation of a gap between the diaper 1 and the wearer's skin that can be a liquid outflow path, the diaper 1 is provided with leg gathers 3AL, 3AR at a portion surrounding the wearer's legs (thighs), and three-dimensional gathers 3BL, 3BR are provided on the inner side of the leg gathers 3AL, 3AR in the width direction of the diaper 1, and a waist gather 3R is provided at a portion surrounding the wearer's abdominal circumference. The leg gathers 3AL, 3AR, the three-dimensional gathers 3BL, 3BR, and the waist gathers 3R are in close contact with the wearer's skin by the contraction force (elastic force) of the stretchable member. Therefore, liquid discharged from the wearer's private parts is absorbed into the absorbent of the diaper 1 without leaking out of the diaper 1. The stretchable member may be selected from thread-like rubber (thread rubber) or strip-like rubber, etc., as appropriate.

[0013] Fig. 2 is an exploded perspective view of the diaper 1. Fig. 3 is a cross-sectional view of the diaper 1 when not worn, cut widthwise at the longitudinal center. Fig. 4 is a plan view of the diaper 1 in a stretched state, as seen from the skin-facing side. Note that the elastic members 4C, 4SL, and 4SR are not shown in Fig. 4. The diaper 1 is made up of a cover sheet 4 which forms the outer surface when worn. The cover sheet 4 is a sheet-like member having a substantially rectangular appearance with constrictions 4KL, 4KR at the portions corresponding to the long sides, and forms the exterior surface of the diaper 1. The constrictions 4KL, 4KR are provided at the portions where the wearer's thighs are located (leg surrounding regions 10L, 10R shown in FIG. 4). The cover sheet 4 is provided to reinforce the back sheet 5 described later and to improve the feel, and may be made of a nonwoven fabric made of a liquid-impermeable thermoplastic resin to suppress leakage of excrement, for example. Examples of liquid-impermeable thermoplastic resins include polyethylene (PE) and polypropylene (PP). The cover sheet 4 is not limited to a single-layer structure, and may be a multi-layer (two-layer) structure having an inner cover sheet and an outer cover sheet. The cover sheet 4 forms the outer peripheral shape (outer shape) of the absorbent pad 1. The cover sheet 4 forms the exterior surface where the front body region 1F, the crotch region 1B, and the back body region 1R are continuously arranged.

[0014] The diaper 1 has a back sheet 5 (an example of the "non-skin-facing sheet" of the present disclosure), an absorbent 6, and a top sheet 7 (an example of the "skin-facing sheet" of the present disclosure) which are laminated in this order on the skin-facing side of the cover sheet 4. The back sheet 5, the absorbent 6, and the top sheet 7 are all sheet-like members having a substantially rectangular appearance, and are laminated in this order on the cover sheet 4 with their longitudinal directions coinciding with the longitudinal direction of the cover sheet 4. The back sheet 5, like the cover sheet 4, is a sheet formed from a water-impermeable thermoplastic resin material to suppress leakage of excrement. The back sheet 5 is preferably made of a material that also has moisture permeability to suppress stuffiness when worn. The top sheet 7 is a sheet-like member disposed on the skin-facing side of the wearer. The top sheet 7 is liquid-permeable in part or in its entirety. Therefore, when the diaper 1 is worn, liquid excreted from the wearer passes through the top sheet 7, which may come into contact with the wearer's skin, into the absorbent 6, and is absorbed therein. For example, a woven fabric, a nonwoven fabric, or a porous film can be used as the material for the top sheet 7. The top sheet 7 may be hydrophilic. The basis weight of the top sheet 7 is, for example, 16 to 35 g / m 2 It is.

[0015] The back sheet 5, the absorbent 6, and the top sheet 7 all extend from the front body region 1F to the rear body region 1R. Therefore, when the cover sheet 4, in which the back sheet 5, the absorbent 6, and the top sheet 7 are laminated, covers the wearer's private parts, the longitudinal ends of the back sheet 5, the absorbent 6, and the top sheet 7 are located on the wearer's ventral side and back side. In other words, the wearer's private parts are covered by the absorbent 6 from the ventral side to the back side. Therefore, whether the wearer is in a ventral or back-down position when excreting liquid, the excreted liquid comes into contact with the absorbent 6 via the top sheet 7. The top sheet 7 and the back sheet 5 are longer in the longitudinal direction than the absorbent 6, and extend to the ends of the front body region 1F and the rear body region 1R of the diaper 1.

[0016] The diaper 1 is provided with elastic members 4SL, 4SR for forming the leg gathers 3AL, 3AR between the cover sheet 4 and the back sheet 5 so as to stretch in the longitudinal direction of the diaper 1. The elastic members 4SL, 4SR are provided in an appropriate number (three in this embodiment) determined according to the elastic force (contractile force) required in the design of the diaper 1. As shown in FIG. 4, the leg gathers 3AL, 3AR are arranged in both widthwise end portions of the crotch region 1B, including the leg surrounding regions where the wearer's thighs are located. The leg surrounding regions 10L, 10R are arranged at both widthwise end portions of the crotch region 1B. The leg gathers 3AL, 3AR are formed in the areas where the elastic members 4SL, 4SR are arranged.

[0017] The diaper 1 also has long, narrow, strip-shaped side sheets 8L, 8R (a pair of leak-proof sheets). The side sheets 8L, 8R are water-impermeable (liquid-impermeable) sheets provided on the long sides of the top sheet 7. Like the cover sheet 4, the side sheets 8L, 8R have constrictions 8KL and 8KL at the regions where the wearer's thighs are located (leg-surrounding regions 10L, 10R shown in FIG. 4). , 8KR are provided on the side sheets 8L, 8R. Elastic members 8EL, 8ER for forming the three-dimensional gathers 3BL, 3BR are arranged on the side sheets 8L, 8R along the longitudinal direction of the diaper 1. When the diaper 1 is in a worn state, i.e., when the diaper 1 is in a U-shaped form in a side view, the side sheets 8L, 8R are pulled in the longitudinal direction by the contractile force of the elastic members 8EL, 8ER and rise from the top sheet 7 to form the three-dimensional gathers 3BL, 3BR that prevent the outflow of liquid.

[0018] The cover sheet 4 is provided with elastic members 4C, which prevent a gap from being formed between the diaper 1 and the wearer's abdominal circumference, on the inner side in the width direction of the diaper 1 than the elastic members 4SL, 4SR and along the longitudinal direction of the diaper 1. The elastic members 4C are provided according to the elastic force (contractile force) and other factors required for the design of the diaper 1.

[0019] The elastic member 9ER for forming the waist gathers 3R is disposed on the waist sheet 9R provided between the back sheet 5 and the top sheet 7 at a position further back than the end of the absorbent body 6. The waist sheet 9R is disposed between the top sheet 7 and the back sheet 5 at a position farther from the absorbent body 6 than the end of the rear body region 1R side of the absorbent body 6 on the tip side (the rear end side of the diaper 1), and is a sheet-like member extending wider in the width direction than the absorbent body 6. The waist sheet 9R is formed by laminating two nonwoven fabric sheets, and the elastic member 9ER is bonded between the two nonwoven fabric sheets in a stretched state in the width direction of the diaper 1. The elastic member 9ER is disposed on the waist sheet 9R with its longitudinal direction, which is the stretch direction, oriented in the left-right direction of the diaper 1. For this reason, the waist sheet 9R has contractibility in the width direction of the diaper 1, and functions as a strip-shaped elastic member together with the elastic member 9ER. When the tapes 2L, 2R provided on both the left and right sides of the waist sheet 9R are attached to the front patch 2F on the abdominal side of the wearer, the elastic member 9ER exerts a contractile force to fit the diaper 1 to the wearer and prevent the formation of a gap between the diaper 1 and the wearer's abdominal circumference.

[0020] A waist sheet 9F is provided between the back sheet 5 and the top sheet 7 at a position further to the ventral side than the end of the absorbent body 6. The waist sheet 9F is disposed between the top sheet 7 and the back sheet 5 at a position further away from the absorbent body 6 than the end of the front body region 1F side of the absorbent body 6 on the tip side (the front end side of the diaper 1), and is a sheet-like member that extends wider in the width direction than the absorbent body 6. The waist sheet 9F is formed by laminating two nonwoven fabric sheets, similar to the waist sheet 9R. Note that no elastic member is disposed in the waist sheet 9F, and therefore the waist sheet 9F does not have contractibility. Note that the basis weight of the waist sheets 9F and 9R is 7 to 10 g / m 2 It is.

[0021] In the present application, the state in which sheets are overlapped is not limited to a state in which the overlapping sheets are in full contact with each other, but includes a concept including a state in which the sheets are partially overlapping each other. In addition, the state in which sheets are bonded to each other includes a concept including a state in which another sheet is interposed between the sheets and the sheets are bonded to each other via the other sheet.

[0022] Next, the absorbent body 6 will be described. The absorbent body 6 according to this embodiment has a substantially rectangular shape. In the diaper 1 according to this embodiment, the absorbent core 6C is not made of pulp. That is, the absorbent body 6 does not contain pulp. The absorbent body 6 has a configuration in which the proportion of SAP is relatively high.

[0023] Fig. 5 is a cross-sectional view showing the absorbent body 6 extracted from the cross-sectional view of Fig. 3. The absorbent body 6 has an absorbent core 6C and a core wrap sheet 6W (an example of the "water-permeable sheet" of the present disclosure) that wraps the absorbent core 6C. The core wrap sheet 6W is composed of a sheet that has water permeability at least on the skin-facing side, and allows liquid that has passed through the top sheet 7 to flow into the absorbent core 6C. In this embodiment, the core wrap sheet 6W is composed of two tissues. One of the two tissues is placed on the non-skin side, folded into the widthwise end of the skin side, and bonded to the other tissue placed on the skin side, including the widthwise end of the skin side. In this way, the core wrap sheet 6W covers the skin side and non-skin side of the absorbent core 6C, enveloping it and preventing the absorbent core 6C from losing its shape. The core wrap sheet 6W may be composed of a single sheet.

[0024] The absorbent core 6C has a layered structure in which, from the non-skin facing side, a flow guide layer 60A, a lower SAP layer 60B, a base layer 60C, an upper SAP layer 60D, and a diffusion layer 60E are laminated. The flow guide layer 60A and the diffusion layer 60E are formed of nonwoven fabric. The flow guide layer 60A has the function of diffusing urine throughout the entire absorbent core 6C on the non-skin facing side. The diffusion layer 60E has the function of diffusing urine throughout the entire absorbent core 6C on the skin facing side. In this embodiment, the flow guide layer 60A and the diffusion layer 60E have a basis weight of 45 g / m 2 The flow guide layer 60A is formed of an air-laid nonwoven fabric. The thickness of the flow guide layer 60A is 300 to 700 μm.

[0025] The lower SAP layer 60B is formed by bonding a large number of SAP (Super Absorbent Polymer) particles to the skin-facing side of the flow guidance layer 60A with a hot melt adhesive. In this way, the lower SAP layer 60B, which is formed by containing SAP particles, a super absorbent polymer, is disposed on the skin-facing side of the flow guidance layer 60A. The upper SAP layer 60D is formed by bonding a large number of SAP particles to the non-skin-facing side of the diffusion layer 60E with a hot melt adhesive. In this way, the upper SAP layer 60D, which is formed by containing SAP particles, a super absorbent polymer, is disposed on the non-skin-facing side of the diffusion layer 60E. In this way, in this embodiment, two SAP layers are formed in the absorbent core.

[0026] In this embodiment, the SAP particles refer to a resin composition containing SAP in a granular form. The term "SAP-containing resin composition" as used herein includes both a composition consisting of SAP alone and a composition containing SAP as the main component and containing other substances to the extent that they do not adversely affect the water absorption. Examples of "other substances" include additives (such as surface modifiers added to make the particle surface hydrophobic) and unreacted monomers remaining during the synthesis of SAP.

[0027] The base layer 60C is disposed between the two SAP layers and is made of a bulky air-through nonwoven fabric. The base layer 60C diffuses liquids such as urine to the lower SAP layer 60B and the upper SAP layer 60D. The absorbent body 6 can absorb and retain liquids such as urine by the entire lower SAP layer 60B and upper SAP layer 60D.

[0028] Fig. 6 is a cross-sectional view of the diaper 1 when not being worn, cut longitudinally at the widthwise centre. As shown in Fig. 6, the core wrap sheet 6W is not bonded at the skin-facing side and non-skin-facing side at the longitudinal end sides of the diaper 1. The reason for this non-adhesion will be described later. The waist sheets 9F, 9R are bonded at their skin-facing sides to the top sheet 7, and at their non-skin-facing sides to the back sheet 5. For example, a hot melt adhesive is used for this adhesion.

[0029] When the absorbent core is made of pulp, the SAP particles are entangled with the pulp fibers and are unlikely to fall off from the absorbent core. However, in this embodiment, the absorbent core does not contain pulp, and the SAP particles are bonded to the flow guide layer 60A and the diffusion layer 60E, which are made of airlaid nonwoven fabric. In an absorbent body 6 having such a configuration, the SAP particles are not entangled with the fibers, etc., and the SAP particles are likely to fall off at the end sides of the absorbent body 6 in the width direction and length direction.

[0030] Although the SAP particles of the lower SAP layer 60B are adhered to the flow guide layer 60A by a hot melt adhesive, some SAP particles peel off and fall off from the flow guide layer 60A. The diaper 1 according to the embodiment may contain loose SAP particles. If no special measures are taken, the SAP particles may leak out of the diaper. For example, if a gap is formed between the top sheet and the back sheet, the SAP particles that have fallen off the absorbent body may spread to the longitudinal end sides of the diaper and leak out from between the top sheet and the back sheet.

[0031] Therefore, the diaper 1 according to this embodiment includes waist sheets 9F, 9R arranged at the end side of the absorbent body 6 in the longitudinal direction. The top sheet 7 and the back sheet 5 are weakly bonded or non-bonded to each other at the end side of the absorbent body 6, i.e., between the absorbent body 6 and the waist sheets 9F, 9R. More specifically, the top sheet 7 and the back sheet 5 are weakly bonded or non-bonded in the areas D1 and D2 shown in FIG. 6. D1 is the distance between the absorbent body 6 and the waist sheet 9R on the side of the rear body region 1R. D2 is the distance between the absorbent body 6 and the waist sheet 9F on the side of the front body region 1F. The specific lengths of D1 and D2 are omitted. Here, the term "weakly bonded" refers to an adhesive strength that allows the sheets bonded to each other to be peeled off without tearing, and is an adhesive strength that is expected to cause the sheets to naturally peel off due to the action (for example, the contraction force of an elastic member) that occurs when the diaper 1 is worn. By making the top sheet 7 and the back sheet 5 non-bonded or weakly bonded in the regions D1 and D2, the SAP particles fall off the lower SAP layer 60B and the upper SAP layer 60D, enter between the top sheet 7 and the back sheet 5, and peel them off, forming a space (hereinafter sometimes referred to as the "SAP storage space") between the top sheet 7 and the back sheet 5, and the SAP particles can be stored in the SAP storage space. In addition, since the waist sheets 9F and 9R are arranged on the longitudinal end side of the SAP storage space, the SAP particles are prevented from moving toward the end side of the waist sheets 9F and 9R. Since the waist sheets 9F and 9R are bonded relatively strongly to the top sheet 7 and the back sheet 5, the SAP storage space is prevented from communicating with the outside of the diaper 1, and the leakage of the SAP particles to the outside can be prevented. Furthermore, since the waist sheets 9F, 9R are wider than the absorbent body 6, even if SAP particles that have leaked into the SAP storage space move in the width direction, the waist sheets 9F, 9R can suppress the leakage of the SAP particles.

[0032] In addition, in the region D2, when the top sheet 7 and the back sheet 5 are not bonded, no hot melt adhesive is applied between the top sheet 7 and the back sheet 5, and when the top sheet 7 and the back sheet 5 are weakly bonded, a small amount of hot melt adhesive is applied between the top sheet 7 and the back sheet 5, so that the region D2 has a relatively low rigidity and is easily folded. Here, when the hook portions of the tapes 2L and 2R in the worn state of the diaper 1 are attached to the loop portions of the front patch 2F and the front (abdominal) ends of the tapes 2L and 2R overlap with the region D2 in the thickness direction, the diaper 1 is easily folded toward the non-skin side in front of the front ends. In this way, when the top sheet 7 and the back sheet 5 in the worn state of the diaper 1 are folded toward the non-skin side in the region D2, the SAP particles can be blocked at the folded portion.

[0033] Moreover, the waist sheets 9F, 9R have a thickness larger than the average particle size of the SAP particles. For example, the average particle size of the SAP particles is 350 μm, and the particle size is set to be 150 to 650 μm. The waist sheets 9F, 9R are thicker than the particle size of the SAP particles, for example, 0.8 mm or more. Even if the SAP particles move into the SAP storage space, the SAP storage space is located between the absorbent body 6 and the waist sheets 9F, 9R, so that the thickness of the absorbent body 6 and the waist sheets 9F, 9R can prevent the SAP in the SAP storage space from touching the wearer's skin surface via the top sheet 7. This makes it possible for the diaper 1 to prevent the thickness of the SAP particles that have moved into the SAP storage space from being felt by the wearer, or from feeling like a foreign body.

[0034] Furthermore, when the distances D1, D2 between the absorbent body 6 and the waist sheets 9F, 9R are set to 10 mm or less, the skin of the wearer's abdomen and back is curved, so that the skin is unlikely to come into contact with the top sheet 7 above the SAP storage space, and the SAP does not give a foreign body sensation to the skin even when body pressure is applied to the diaper 1. By setting the absorbent body 6 and the waist sheets 9F, 9R to a thickness of 1 mm or more, the wearer's skin comes into contact with the absorbent body 6 and the waist sheets 9F, 9R, and the wearer's skin is prevented from coming into contact with the SAP in the SAP storage space. Therefore, the diaper 1 can prevent the wearer from feeling uncomfortable due to contact with SAP particles.

[0035] Moreover, each distance D1, D2 between the absorbent body 6 and the waist sheets 9F, 9R in the longitudinal direction of the diaper 1 is preferably at least twice the average particle size of the SAP particles. More preferably, each distance D1, D2 is at least 10 times the average particle size of the SAP particles. When the SAP particles fall off the lower SAP layer 60B and the upper SAP layer 60D and a space for storing SAP is formed between the top sheet 7 and the back sheet 5, by setting each distance between the absorbent body 6 and the waist sheets 9F, 9R as described above, it is possible to prevent the force of the SAP particles peeling the top sheet 7 and the back sheet 5 from acting on the adhesion between the waist sheets 9F, 9R and the top sheet 7 and the back sheet 5. Therefore, the diaper 1 can prevent the waist sheets 9F, 9R from peeling off the top sheet 7 and the back sheet 5, and suppress leakage of the SAP particles.

[0036] In addition, the waist sheet 9F on the front body region 1F side does not have contractility. Therefore, in the front body region 1F side, the core wrap sheet 6W is not subjected to a contraction force in the width direction, and the core wrap sheet 6W is prevented from opening in the thickness direction. In addition, when a contraction force is applied to the absorbent 6, the SAP particles are likely to fall off from the lower SAP layer 60B and the upper SAP layer 60D, but in the front body region 1F side, the absorbent 6 is not subjected to a contraction force, and the SAP particles are less likely to fall off.

[0037] The crotch region side of the waist sheet 9F and the back sheet 5 may be weakly bonded or not bonded at all. This forms a space for storing SAP between the crotch region side of the waist sheet 9F and the back sheet 5, and when SAP particles are stored in the space, the waist sheet 9F is disposed closer to the skin than the space, thereby reducing the contact with the skin (foreign body sensation) of the SAP particles in the space. As described above, the top sheet 7 and the back sheet 5 bend away from the skin in the region within D2 when worn, thereby further reducing the contact with the skin of the SAP particles in the space.

[0038] As shown in FIG. 4, the three-dimensional gathers 3BL, 3BR formed by the side sheets 8L, 8R and the elastic members 8EL, 8ER are arranged along the widthwise end of the top sheet 7 and extend in the longitudinal direction of the diaper 1. The side sheets 8L, 8R are joined to the widthwise end of the top sheet 7. A hot melt adhesive is used for this joining. The side sheets 8L, 8R are bonded to the top sheet 7 and the cover sheet 4 on the widthwise outer side of the fold lines 30L, 30R extending in the longitudinal direction, and are not bonded to the top sheet 7 on the inner side of the fold lines 30L, 30R. Therefore, when the diaper 1 is worn, the inner side of the fold lines 30L, 30R of the side sheets 8L, 8R rise toward the skin side due to the contractile force of the elastic members 8EL, 8ER provided on the side sheets 8L, 8R in the longitudinal stretched state of the diaper 1, thereby forming the three-dimensional gathers 3BL, 3BR.

[0039] When the three-dimensional gathers 3BL, 3BR are raised, fixing parts 31L, 31R are formed as starting points in the longitudinal direction of the raised gathers. Note that in FIG. 4, the fixing parts 31L, 31R are blacked out. The fixed parts 31L, 31R are formed on the inside of the fold lines 30L, 30R in the width direction of the diaper 1 and on the end side of the absorbent body 6 in the longitudinal direction. The fixed parts 31L, 31R are formed on both sides of the front body region 1F and the back body region 1R, and each fixed part 31L, 31R is disposed across the absorbent body 6 and the waist sheets 9F, 9R when viewed in the thickness direction. The fixed parts 31L, 31R are formed by applying a hot melt adhesive between the non-skin facing sides of the side sheets 8L, 8R and the top sheet 7. The side sheets 8L, 8R are also fixed to the top sheet 7 by the fixed parts 31L, 31R.

[0040] Here, there is no non-adhesive region between the fixing parts 31L, 31R and between the top sheet 7 and absorbent body 6, and between the top sheet 7 and waist sheet 9F, 9R. The interlayers refer to the interlayers between the sheets, and the top sheet 7 and absorbent body 6, and the top sheet 7 and waist sheet 9F, 9R are adhered on the non-skin-facing side of the fixing parts 31L, 31R. The fixing parts 31L, 31R increase the rigidity of the longitudinal end side of the absorbent body 6. In addition, since the fixing parts 31L, 31R are arranged across the waist sheet 9F, which has no contractile force, contraction of the absorbent body 6 is also suppressed on the front body region 1F side, and therefore, the SAP particles can be prevented from falling off the lower SAP layer 60B and the upper SAP layer 60D on the front side of the absorbent body 6. Furthermore, even if the fixing parts 31L, 31R are disposed across the waist sheet 9R having a contractile force, the rigidity of the absorbent body 6 on the rear body region 1R side can be increased, thereby preventing the rear end of the absorbent body 6 from twisting. Note that, in order to prevent the absorbent body 6 from twisting, the fixing parts 31L, 31R are preferably formed so as to overlap the absorbent body 6 on the end side in the width direction of the absorbent body 6.

[0041] Furthermore, even if the SAP particles leak outside the fold lines 30L, 30R and penetrate between the side sheets 8L, 8R and the top sheet 7 or the back sheet 5, the SAP can be contained in the SAP containing space and the waist sheets 9F, 9R can prevent the SAP particles from leaking to the outside.

[0042] As shown in FIG. 4, the top sheet 7 has embossed grooves 20 formed in a diagonal lattice pattern. The embossed grooves 20 are formed by embossing the top sheet 7 (3D embossing). The top sheet 7 may be formed by laminating two nonwoven fabric sheets, and the embossed grooves 20 may be formed by embossing these two nonwoven fabric sheets. The top sheet 7 may be formed by a single nonwoven fabric sheet, and the embossed grooves 20 may be formed by embossing this nonwoven fabric sheet. The diaper 1 has the embossed grooves 20 formed in the top sheet 7, which makes it difficult for the wearer to feel the particles of the SAP particles contained in the lower SAP layer 60B and the upper SAP layer 60D of the absorbent body 6, and the SAP particles that have fallen off the flow guide layer 60A and the diffusion layer 60E, and thus prevents a decrease in comfort when worn.

[0043] Next, the suppression of ammonia generation in the diaper 1 according to this embodiment will be described with reference to Figs. 3 and 5. The top sheet 7 of the diaper 1 contains an acidifying agent. In this embodiment, citric acid is used as the acidifying agent. The top sheet 7 contains citric acid, thereby suppressing bacterial growth even after the wearer urinates. This allows the diaper 1 to prevent the urea contained in urine from being decomposed by bacterial enzymes (urease), and suppress the generation of ammonia. In addition, the diaper 1 maintains the top sheet 7 at a weak acidity, thereby preventing the skin surface from becoming an alkaline environment in which Staphylococcus aureus and pathogenic bacteria are likely to grow, and suppresses the occurrence of skin troubles on the wearer's skin. In addition, even if ammonia is generated, the diaper 1 can neutralize the ammonia by the citric acid contained in the top sheet 7. The diaper 1 can suppress the generation of ammonia and keep the surface of the top sheet 7 at a weak acidity.

[0044] Furthermore, as a result of intensive research, the inventors of the present application found that a layer of an acidic aqueous solution was added to the non-skin-facing side of the absorbent core 6C. By forming the absorbent 6, the generation of ammonia can be further suppressed. In the diaper 1 according to this embodiment, an absorbent 6 is created in which the acidic water content of urine remains in the flow guide layer 60A of the absorbent core 6C, so that a layer of an acidic aqueous solution can be formed on the non-skin facing side of the absorbent core 6C.

[0045] The amount of moisture remaining in the flow guide layer 60A of the diaper 1 was measured by the following moisture absorption test. First, a sample diaper is prepared. In this embodiment, a diaper for infants is prepared. The sample diaper is attached in an extended state to a drawing board, and marks are made at the center of the absorbent, 100 mm forward from the center (hereinafter referred to as the "ventral side"), and 100 mm backward from the center (hereinafter referred to as the "dorsal side"), and 50 mL of artificial urine is poured from the top sheet 7 toward the center, ventral side, and dorsal side of the absorbent. After confirming that the absorbent has absorbed the artificial urine, the pH and moisture content are measured at three points on the top sheet 7 and the flow guide layer 60A at the center, ventral side, and dorsal side of the absorbent. Next, after 5 minutes, another 50 mL of artificial urine is poured in the same way, and the pH value and moisture content are measured at three points on the top sheet 7 and the flow guide layer at the center, ventral side, and dorsal side of the absorbent. 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. In addition, the moisture content was measured using a high-performance moisture meter MY-808S manufactured by Scalar, and the pH value was measured using an everyday waterproof portable pH meter HI99181N.

[0046] In this embodiment, diaper samples No. A1 to A7 were prepared. In each sample, the SAP basis weight of the lower SAP layer 60B was 160 g / m 2 , 165g / m 2 , 170g / m 2 , 175g / m 2 , 180g / m 2 , 185g / m 2 , 190g / m 2 The basis weight of the SAP of the upper SAP layer 60D was set to 190 g / m for each sample. 2The other structures of the absorbent body 6 and the basis weight of the top sheet 7 are as described above. The pH value of the flow guide layer 60A before urine absorption is 4.9. The top sheet 7 may be made of an air-through nonwoven fabric, a spunbond nonwoven fabric, a spunlace nonwoven fabric, or the like.

[0047] 7 is a table showing the pH value and moisture content at the center, ventral side, and dorsal side of the absorbent body for each sample when 50 mL of artificial urine was poured, the pH value and moisture content at the time when 100 mL of artificial urine was poured, and the average pH value and moisture content. As shown in the table in FIG. 7, the SAP basis weight of the lower SAP layer 60B is 180 g / m 2 In Nos. A1 to A4, where the basis weight of the SAP in the lower SAP layer 60B was less than 180 g / m, moisture remained in the flow guide layer 60A and little moisture remained in the top sheet 7, resulting in pH values ​​that were approximately the same in the top sheet 7 and the flow guide layer 60A. This can be seen from the fact that an acidic aqueous solution layer containing dissolved citric acid was formed in the flow guide layer 60A, which changed the pH value of the flow guide layer 60A from the initial value of 4.9 to around 4.3 to 4.4, which is more acidic. On the other hand, when the basis weight of the SAP in the lower SAP layer 60B was 180 g / m 2 In the above Nos. A5 to A7, the pH value of the flow conducting layer 60A remained almost unchanged from the initial value of 4.9. Thus, the measurement of the pH value of the flow conducting layer 60A revealed that a layer of an acidic aqueous solution containing dissolved citric acid was formed in the flow conducting layer 60A. The basis weight of the SAP of the lower SAP layer 60B was set to 100 g / m2, taking into account the amount of liquid absorbed and retained. 2 More preferably, it is equal to or greater than this.

[0048] The moisture remaining in the flow guide layer 60A is acidic due to the dissolved citric acid contained in the top sheet 7. The diaper 1 can suppress the generation of ammonia by leaving acidic moisture in the flow guide layer 60A even after the wearer urinates. In addition, the basis weight of the SAP of the lower SAP layer 60B is 180 g / m 2 By setting the absorption amount to less than 370 g, moisture can be left in the flow guide layer 60A. The liquid absorption amount of the lower SAP layer 60B is preferably 370 g or less. The liquid absorption amount of the lower SAP layer 60B can be calculated by multiplying the SAP amount by the water absorption capacity of the SAP.

[0049] In this way, the diaper 1 according to the present embodiment prevents the activation of enzymes by leaving acidic moisture in the flow guide layer 60A, suppresses the generation of ammonia that occurs when the enzyme decomposes urea, and prevents the inside of the diaper from becoming alkaline. This can prevent skin problems from occurring in the patient.

[0050] Next, the basis weight of the SAP of the upper SAP layer 60D for allowing acidic moisture to remain in the flow guide layer 60A was examined by the above-mentioned moisture absorption test. Diaper samples No. B1 to B7 were prepared. In each sample, the basis weight of the SAP of the upper SAP layer 60D was 170 g / m 2 , 175g / m 2 , 180g / m 2 , 185g / m 2 , 190g / m 2 , 195g / m 2 , 200g / m 2 The basis weight of the SAP of the lower SAP layer 60B was set to 170 g / m for each sample. 2 The other structures of the absorbent body and the basis weight of the top sheet 7 were as described above.

[0051] 8 is a table showing the pH value and moisture content at the center, ventral side, and dorsal side of the absorbent body for each sample when 50 mL of artificial urine was poured, the pH value and moisture content at the time when 100 mL of artificial urine was poured, and the average pH value and moisture content. As shown in the table of FIG. 8, the upper SAP layer 60D had a basis weight of 190 g / m 2 In the above Nos. B5 to B7, moisture remained in the flow guide layer 60A and little moisture remained in the top sheet 7, and the pH values ​​were approximately the same in the top sheet 7 and the flow guide layer 60A. This is because a layer of an acidic aqueous solution containing dissolved citric acid was formed in the flow guide layer 60A, causing the pH value of the flow guide layer 60A to change from the initial value of 4.9 to around 4.3 to 4.4, which is more acidic. On the other hand, the basis weight of the SAP of the upper SAP layer 60D was 190 g / m 2In Nos. B1 to B4, the pH value of the flow guide layer 60A did not change much from the initial value of 4.9. As can be seen from the results shown in FIG. 8, the basis weight of the SAP of the upper SAP layer 60D was 190 g / m 2 By setting the liquid absorption capacity to 380 g or more, moisture can be left in the flow guide layer 60A. The liquid absorption capacity of the upper SAP layer 60D is preferably 380 g or more. The liquid absorption capacity of the upper SAP layer 60D can be calculated by multiplying the SAP amount by the water absorption ratio of the SAP. The diaper 1 according to this embodiment can compensate for the insufficient absorption capacity of the lower SAP layer 60B by absorbing liquids such as urine with the upper SAP layer 60D, which has a relatively large liquid absorption capacity. Furthermore, in the diaper 1, moisture tends to collect in the upper SAP layer 60D, and moisture tends to remain in the flow guide layer 60A below the lower SAP layer 60B. The basis weight of the SAP of the upper SAP layer 60D is set to 300 g / m2, taking into account the liquid absorption and retention capacity, etc. 2 It is preferable that:

[0052] <Modification> Next, a diaper according to a modification of this embodiment will be described with reference to Figs. 5 and 9. In the diaper 1 according to this modification, the flow guide layer 60A contains pulp. For example, an airlaid nonwoven fabric made of pulp or an airlaid nonwoven fabric containing pulp and synthetic fibers may be used for the flow guide layer 60A. In this modification, the basis weight of the SAP of the lower SAP layer 60B for retaining moisture in the flow guide layer 60A was also examined by the moisture absorption test described above. In this modification, diaper samples Nos. C1 to C7 were prepared. In each sample, the basis weight of the SAP of the lower SAP layer 60B was 160 g / m 2 , 165g / m 2 , 170g / m 2 , 175g / m 2 , 180g / m 2 , 185g / m 2 , 190g / m 2 The basis weight of the SAP of the upper SAP layer 60D was set to 190 g / m for each sample. 2 The other structures of the absorbent body and the basis weight of the top sheet 7 were as described above.

[0053] 9 is a table showing the pH value and moisture content at the center, ventral side, and dorsal side of the absorbent body for each sample when 50 mL of artificial urine was poured, the pH value and moisture content at the time when 100 mL of artificial urine was poured, and the average pH value and moisture content. As shown in the table in FIG. 9, the SAP basis weight of the lower SAP layer 60B is 180 g / m 2 In Nos. C1 to C4, where the basis weight of the SAP in the lower SAP layer 60B was less than 180 g / m, moisture remained in the flow guide layer 60A and little moisture remained in the top sheet 7, resulting in pH values ​​that were approximately the same in the top sheet 7 and the flow guide layer 60A. This can be seen from the fact that an acidic aqueous solution layer containing dissolved citric acid was formed in the flow guide layer 60A, which changed the pH value of the flow guide layer 60A from the initial value of 4.9 to around 4.3 to 4.4, which is more acidic. On the other hand, when the basis weight of the SAP in the lower SAP layer 60B was 180 g / m 2 In Nos. C5 to C7, the pH value of the conducting layer 60A increased from the initial value of 4.9. Therefore, even in the modified example, the basis weight of the SAP of the lower SAP layer 60B was 180 g / m 2 By leaving acidic moisture in the flow guide layer 60A, the diaper 1 according to this modification can prevent the activation of enzymes and suppress the generation of ammonia that occurs when the enzymes decompose urea.

[0054] Next, we will explain the reason why the skin-facing side and non-skin-facing side of the core wrap sheet 6W are not bonded at the longitudinal end sides of the diaper 1. In the manufacturing process of the diaper 1 according to this embodiment, the absorbent body 6 is formed for one diaper 1 by cutting a continuous body along the width direction, and is incorporated into the diaper 1. Therefore, the longitudinal end sides of the absorbent body 6 remain in a state where they are cut from the continuous body, and the skin-facing side and non-skin-facing side of the core wrap sheet 6W are not bonded at the same end sides.

[0055] Here, the continuum of absorbent bodies 6 will be described. FIG. 10 is a diagram showing an example of a manufacturing apparatus for diapers according to an embodiment. The manufacturing apparatus M1 includes a manufacturing apparatus main body M2 and a lifting apparatus M3. The manufacturing apparatus main body M2 is an apparatus for assembling diapers using various materials such as nonwoven fabric, absorbent bodies, rubber thread, and film. The lifting apparatus M3 is an elevator device capable of mounting a continuum 600 of absorbent bodies 6, which is one of the materials used by the manufacturing apparatus main body M2, on a platform. The continuum 600 is folded in an accordion-like shape.

[0056] The manufacturing apparatus main body M2 is, for example, an apparatus for continuously taking in a long material wound in a roll shape and assembling an absorbent article. Thus, the manufacturing apparatus main body M2 takes in, for example, the continuous body 600 mounted on the lifting device M3 from the top to assemble the diaper 1.

[0057] The manufacturing device M1 is installed in a building of a manufacturing plant T. The building of the manufacturing plant T has a hierarchical structure. The manufacturing device main body M2 is installed on the upper floor F2 of the manufacturing plant T, and the lifting device M3 is installed on the lower floor F1 of the manufacturing plant T. The lower floor F1 is lower than the upper floor F2. The lifting device M3 installed on the lower floor F1 has a height that reaches the upper floor F2. The lifting device M3 is installed so that its upper part is located near the take-in part of the continuous body 600 provided in the manufacturing device main body M2. For this reason, rollers M4 are provided near the take-in part of the continuous body 600 provided in the manufacturing device main body M2 to prevent the continuous body 600, which is pulled up from a position lower than the upper floor F2 and taken into the manufacturing device main body M2, from contacting the upper floor F2. In the manufacturing apparatus M1 of this embodiment, the continuum 600 supplied from the lifting device M3 toward the upper side in the direction of gravity is taken into the take-in section of the manufacturing apparatus main body M2 from the lower side in the direction of gravity. Then, in the manufacturing apparatus main body M2, the continuum 600 is taken in horizontally from the take-in section. Therefore, the roller M4 changes the traveling direction of the continuum 600 supplied from the lower side in the direction of gravity to the horizontal direction. Since the roller M4 is provided in the take-in section of the manufacturing apparatus M1, the manufacturing apparatus M1 can take in the continuum 600, which leaves the lifting device M3 and heads toward the upper side in the direction of gravity, into the take-in section without contacting any object until it touches the roller M4 of the take-in section.

[0058] When the accordion-shaped folded continuum 600 is unfolded during intake, the SAP particles tend to fall off the flow guide layer 60A and the diffusion layer 60E. Even if the diaper 1 contains such fallen SAP particles, the diaper 1 is provided with waist sheets 9F, 9R and is therefore able to prevent the SAP particles from leaking out.

[0059] FIG. 11 is a diagram showing an outline of the SAP fixation rate test. FIG. 11 shows a device for investigating the extent to which SAP particles are fixed to the absorbent body 6. A pole stands vertically from a base 100, and a guide rail 101 with a length of 10 cm is installed vertically above the pole. A drop rod 102 is placed inside the guide rail 101. The experimenter When the user lifts the drop bar 102 to the upper end of the guide rail 101 and releases it, the drop bar 102 falls freely along the guide rail 101 for 10 cm.

[0060] The absorbent body 6 is placed on the drop rod 102. An electronic balance 103 for weighing the dropped SAP particles is provided directly below the drop rod 102. In this state, the drop operation is repeated 20 times to weigh the SAP particles that are not fixed inside the absorbent body 6. If the amount of SAP that has fallen off is DR and the amount of SAP that is designed to be blended into the absorbent body 6 is DF, the fixation rate (%) of SAP can be calculated by the following formula (1). Fixation rate of SAP particles = (1-DR / DF) × 100 (1)

[0061] In this embodiment, when the SAP fixation rate test was performed on the absorbent body 6, the fixation rate of SAP particles was 91%. Even though the diaper 1 according to this embodiment includes the absorbent body 6 with a fixation rate of SAP particles of 91%, the diaper 1 according to this embodiment is able to prevent the SAP particles from leaking out because it includes the waist sheets 9F, 9R.

[0062] <Other embodiments> Although the present embodiment has been described above, the contents of the present invention are not limited to the above embodiment. In the above embodiment, a tape-type disposable diaper has been described as an example, but the present invention is not limited to this, and the present invention can also be applied to absorbent articles such as absorbent pads and pants-type disposable diapers.

[0063] In addition, in the above embodiment, citric acid is used as the acidifying agent, but the present invention is not limited to this.

[0064] The features included in each of the embodiments and the modified examples thereof disclosed above can be combined with each other. [Explanation of symbols]

[0065] 1. Diapers 1B...Inseam area 1F: Front body area 1R: Back body area 2L, 2R Tape 2F: Front patch 3BL, 3BR...Expansion member 3L, 3R: 3D gathers 4. Cover sheet 5. Back sheet 6. Absorber 6C··Absorbent core 6W··Core wrap sheet 7. Top sheet 8R, 8L··Side seat 8EL, 8ER... Elastic material 9F, 9R: West seat 9ER··Expansion member 20 Embossed groove 30L, 30R ·· Folding line 31L,31R·Fixed part 60A･･･Driving layer 60B...Lower SAP layer 60C·Base layer 60D...Top SAP layer 60E Diffusion layer 600··Continuum

Claims

1. A length along a longitudinal direction corresponding to the front-to-back direction of the wearer; A length along a width direction perpendicular to the longitudinal direction; From the non-skin facing side, the flow guide layer, the highly absorbent polymer SAP having a basis weight of 180 g / m ２ an absorbent body having an absorbent core in which a lower SAP layer, a base layer, an upper SAP layer, and a diffusion layer are laminated, and the lower SAP layer has a thickness of less than 1 mm and a liquid absorption capacity of 370 g or less; and a water-permeable sheet covering the non-skin-facing side and the skin-facing side of the absorbent core; a skin-facing sheet that is disposed on the skin-facing side of the absorbent body, has water permeability, and contains an acidifying agent; a non-skin-facing sheet that is disposed on the non-skin-facing side of the absorbent body and has water impermeability; An absorbent article comprising:

2. The basis weight of the SAP of the upper SAP layer is 190 g / m ２ That's all. The absorbent article of claim 1.

3. The liquid absorption capacity of the upper SAP layer is 380 g or more. The absorbent article according to claim 1 or 2.

4. The thickness of the flow guide layer is 300 μm or more and 700 μm or less. The absorbent article according to claim 1 or 2.

5. The flow guide layer is made of an airlaid nonwoven fabric. The absorbent article according to claim 1 or 2.

6. The flow guide layer comprises pulp. The absorbent article according to claim 1 or 2.

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