Absorbent article

Abstract

To enhance the effect relative to the amount of inorganic antibacterial particles used in an absorber when the inorganic antibacterial particles are incorporated in the absorber.SOLUTION: An absorbent article comprises an absorber and a top sheet covering the front side of the absorber, the absorber being formed by accumulation of pulp fibers, wherein at least a part of the absorber retains antibacterial granules 30 in a dispersed state, the antibacterial granules 30 contain more than 0 wt.% and less than 50 wt.% of an inorganic antibacterial agent 31, and the antibacterial granules 30 have an average particle diameter of 250-500 μm.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to absorbent articles, including disposable diapers, sanitary napkins, and pet sheets. [Background technology]

[0002] This type of absorbent article generally comprises an absorbent body, a liquid-permeable top sheet covering the front side of the absorbent body, and a liquid-impermeable sheet covering the back side of the absorbent body, and excretory fluids such as urine and menstrual blood pass through the top sheet and are absorbed and retained by the absorbent body. The absorbent body (also called an absorbent core) generally contains pulp fibers and highly absorbent polymer particles.

[0003] On the other hand, it is also known that antibacterial particles are contained in the absorbent body of the absorbent article to impart deodorizing, antibacterial, and other functions.

[0004] However, because a large surface area is important for commonly used inorganic antibacterial particles, many of them have small particle sizes on the order of 10 μm, which poses the problem that they tend to escape from the absorbent (are difficult to retain). Simply increasing the particle size of the inorganic antibacterial particles to solve this problem reduces the surface area, reducing the effectiveness relative to the amount used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-145648 [Patent Document 2] Japanese Patent Application Publication No. 2018-166937 [Patent Document 3] Japanese Patent Application Laid-Open No. 2018-166940 [Patent Document 4] Japanese Patent Application Publication No. 2019-162401 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, a main object of the present invention is to improve the effect relative to the amount of inorganic antibacterial particles used when inorganic antibacterial particles are mixed into an absorbent. [Means for solving the problem]

[0007] The absorbent article that solves the above problems is as follows. <First aspect> The absorbent body has an absorbent body and a top sheet that covers the front side of the absorbent body, The absorbent article is an absorbent article in which the absorbent body is formed by accumulating pulp fibers, Antibacterial powder particles are dispersed and held in at least a portion of the absorbent body, The antibacterial powder contains more than 0% by weight and less than 50% by weight of an inorganic antibacterial agent, The antibacterial powder has an average particle size of 250 to 500 μm. An absorbent article characterized by:

[0008] (Action and effect) In this absorbent article, the inorganic antibacterial agent is not used as is, but is dispersed in the absorbent material as powder particles that are sufficiently large in diameter but have a low inorganic antibacterial agent content, thereby improving the effectiveness of the inorganic antibacterial agent relative to its amount used.

[0009] <Second aspect> The absorbent body is formed by accumulating pulp fibers, highly absorbent polymer particles, and the antibacterial powder and granules in a mixed state, The highly absorbent polymer particles and the antibacterial powder particles in the absorbent body are not adhered to the inside of the absorbent body, The average particle size of the superabsorbent polymer particles before swelling is 250 to 500 μm, The average particle size of the antibacterial powder and granules is 0.2 to 3.0 times the average particle size of the superabsorbent polymer particles. 1. An absorbent article according to a first embodiment.

[0010] (Action and effect) Furthermore, by making the sizes of the superabsorbent polymer particles and antibacterial powder particles mixed into the pulp fibers uniform or similar, the superabsorbent polymer particles and antibacterial powder particles can be more uniformly dispersed and mixed within the absorbent body, and not only the retention of the antibacterial powder particles within the absorbent body but also the retention of the superabsorbent polymer particles is improved.

[0011] <Third aspect> The basis weight of the pulp fibers in the absorbent body is 70 to 700 g / m 2 and the weight ratio of pulp fibers to superabsorbent polymer particles in the absorbent body is 9:1 to 3:7; The weight ratio of pulp fiber to antibacterial powder and granules in the absorbent body is 20:1 to 2:1. An absorbent article according to a second embodiment.

[0012] (Action and effect) The blending ratio of the pulp fibers, the highly absorbent polymer particles, and the antibacterial powder particles can be determined as appropriate, but it is particularly preferable that the blending ratio is within the range of this embodiment.

[0013] <Fourth aspect> The inorganic antibacterial agent elutes antibacterial metal ions upon contact with water in excrement, the antibacterial powder and granules contain a bulking agent and are granules obtained by binding the inorganic antibacterial agents together, the bulking agents together, and the inorganic antibacterial agents and the bulking agent together with a binder; the solidified body of the binder is permeable to the moisture and the metal ions; The absorbent article according to any one of the first to third aspects.

[0014] (Action and effect) Although the inorganic antibacterial agent is not particularly limited, those that elute metal ions such as silver ions are preferred from the viewpoints of safety and availability. When such inorganic antibacterial agents are granulated as described above, they may be molded together with a bulking agent, but considering the average particle size of the antibacterial powder, it is easier to granulate them using a bulking agent and a binder. In this case, however, if the inorganic antibacterial agent is not easily brought into contact with the moisture in the excrement, the antibacterial effect may be insufficient. Therefore, even if granulation is performed using a binder as in this embodiment, it is preferable that the solidified binder be permeable to moisture and the metal ions.

[0015] <Fifth aspect> The antibacterial powder / granule has a content of the inorganic antibacterial agent that increases stepwise or continuously toward the outer surface. An absorbent article according to a fourth embodiment.

[0016] (Action and effect) The distribution of the inorganic antibacterial agent in the antibacterial powder and granules is not limited, but if the inorganic antibacterial agent is distributed as in this embodiment, it is preferable because it makes it easier for the inorganic antibacterial agent to come into contact with the moisture in the excrement, making it easier for the antibacterial effect to be exerted.

[0017] <Sixth aspect> The antibacterial powder and granules have the inorganic antibacterial agent exposed on the outer surface. The absorbent article of the fourth or fifth aspect.

[0018] (Action and effect) When the solidified binder is permeable to moisture and metal ions, the antibacterial powder granules will exhibit sufficient antibacterial activity even if they do not have an inorganic antibacterial agent exposed on the outer surface, which can be said to be more preferable in terms of strength of the antibacterial powder granules, but it is more preferable from the standpoint of antibacterial activity to have an inorganic antibacterial agent exposed on the outer surface.

[0019] <Seventh aspect> a pair of three-dimensional gathers that cover both side edges of the top sheet in the entire front-to-rear direction in an unfolded state; When worn, the three-dimensional gathers have a front-to-back middle portion that rises up from the top sheet to form a barrier, The absorbent body has a two-layer structure consisting of an upper layer and a lower layer, In the unfolded state, both side edges of the upper layer are located between the pair of three-dimensional gathers, the upper layer contains the antibacterial powder and granules, The lower layer does not contain the antibacterial powder and granules. An absorbent article according to any one of the first to sixth aspects.

[0020] (Action and effect) Absorbent articles such as disposable diapers often have upright gathers, as in this embodiment. In absorbent articles with such upright gathers, the portion of the top sheet located between the upright gathers is the area that primarily comes into contact with the skin. Furthermore, when an absorbent article has a two-layer absorber, the width of the upper layer is generally narrower than the width of the lower layer. Therefore, providing an absorbent article with an upper layer that is narrower than the width between a pair of upright gathers, as in this embodiment, and incorporating antibacterial powder particles only in the upper layer, is preferable, since the antibacterial powder particles can be provided only on the back side of the area that primarily comes into contact with the skin. [Effects of the Invention]

[0021] As described above, the present invention provides advantages such as an improvement in the effectiveness of the inorganic antibacterial agent relative to the amount used when the inorganic antibacterial agent is mixed in the absorbent. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a plan view showing the inner surface side of the pad-type disposable diaper in an unfolded state. [Figure 2] FIG. [Figure 3] FIG. 2 is a cross-sectional view of FIG. 1 taken along the line Y-Y. [Figure 4] 2 is a cross-sectional view taken along the line XX in FIG. 1. [Figure 5] FIG. 2 is a plan view showing the inner surface side of the pad-type disposable diaper in an unfolded state. [Figure 6] FIG. 6 is a cross-sectional view of FIG. 5 taken along the line Y-Y. [Figure 7] XX cross-sectional view of FIG. 5. [Figure 8] FIG. 1 is a schematic diagram of antibacterial powder and granules. [Figure 9] 10 is a graph showing test results. DETAILED DESCRIPTION OF THE INVENTION

[0023] Examples of absorbent articles are described in detail below with reference to the accompanying drawings. The term "crotch area" refers to the area that corresponds to the crotch of the body during use. Depending on the product, it may refer to the area from the center or vicinity of the center of the article in the front-to-back direction LD to a predetermined area on the front side, as in the illustrated embodiment, or to a predetermined area in the center of the article in the front-to-back direction LD. When the article has a narrow waisted area in the middle of the front-to-back direction LD or in the middle of the absorbent body 23 in the front-to-back direction LD, it refers to a predetermined area in the front-to-back direction with the narrowest area of ​​either or both waisted areas as the center in the front-to-back direction. Furthermore, "front area (ventral area)" refers to the area in front of the crotch area, and "rear area (dorsal area)" refers to the area behind the crotch area.

[0024] Furthermore, adjacent components in the thickness direction are fixed or joined as necessary, not only in the fixed or joined portions described below, but also in other areas, as in known diapers. The dotted patterns in the cross-sectional diagram indicate adhesives such as hot melt adhesives used as the fixing or joining means. Hot melt adhesives can be applied by known methods, such as slot coating, continuous or dotted bead coating, spiral, Z-shaped, or wavy spray coating, or pattern coating (transfer of hot melt adhesive using a relief printing method). Alternatively or in addition to this, in the fixing portion of the elastic member, hot melt adhesive can be applied to the outer surface of the elastic member to fix the elastic member to the adjacent member. Hot melt adhesives include, for example, EVA-based, adhesive rubber-based (elastomer-based), polyolefin-based, and polyester / polyamide-based types, but are not particularly limited. Material welding methods such as heat sealing and ultrasonic sealing can also be used to fix or join each component. In areas requiring liquid permeability in the thickness direction, adjacent components in the thickness direction are fixed or joined in an intermittent pattern. For example, when such intermittent fixing or joining is performed with a hot melt adhesive, intermittent pattern coating such as spiral, Z-shaped, or wavy can be suitably used, and when coating over an area wider than the coating width of one nozzle, intermittent pattern coating such as spiral, Z-shaped, or wavy can be performed with or without gaps in the width direction.Means for joining the components can also be means for welding materials such as heat sealing or ultrasonic sealing.

[0025] Furthermore, as the nonwoven fabric in the following description, known nonwoven fabrics can be used as appropriate depending on the location and purpose. The constituent fibers of the nonwoven fabric can be selected without particular limitation, for example, synthetic fibers such as polyolefins (e.g., polyethylene or polypropylene), polyesters, and polyamides (including single-component fibers as well as core-sheath and other composite fibers), regenerated fibers (e.g., rayon or cupra), and natural fibers (e.g., cotton), and mixtures of these can also be used. To increase the flexibility of the nonwoven fabric, it is preferable to use crimped fibers as the constituent fibers. Furthermore, the constituent fibers of the nonwoven fabric can be hydrophilic fibers (including fibers made hydrophilic by a hydrophilizing agent), hydrophobic fibers, or water-repellent fibers (including fibers made water-repellent by a water-repellent agent). Furthermore, nonwoven fabrics are generally classified into staple fiber nonwoven fabrics, long fiber nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, thermal bond (air-through) nonwoven fabrics, needle-punched nonwoven fabrics, point-bond nonwoven fabrics, laminated nonwoven fabrics (including SMS nonwoven fabrics and SMMS nonwoven fabrics in which a meltblown layer is sandwiched between spunbond layers), etc. depending on the fiber length, sheet formation method, fiber bonding method, and laminated structure, and any of these nonwoven fabrics can be used.

[0026] 1 to 4 show a pad-type disposable diaper 200 as an example of an absorbent article. This pad-type disposable diaper 200 has a crotch region C2 and a front region F2 and a rear region B2 extending on both the front and rear sides of the crotch region C2. However, these regions may be omitted (smaller) or other regions may be added (larger). The dimensions of each region may be determined as appropriate. For example, the overall length (front-to-rear direction) L of the diaper may be approximately 350 to 700 mm, and the overall width W1 may be approximately 130 to 400 mm (but wider than the width of the absorbent surface of the diaper). In this case, the length (front-to-rear direction LD) of the crotch region C2 may be approximately 10 to 150 mm, the length (front-to-rear direction) of the front region F2 may be approximately 50 to 350 mm, and the length (front-to-rear direction) of the rear region B2 may be approximately 50 to 350 mm. The width W3 of the crotch region C2 for adults may be 150 mm or more, particularly approximately 200 to 260 mm.

[0027] The pad-type disposable diaper 200 has a basic structure in which an absorber 23 is interposed between a liquid-impermeable sheet 21 and a liquid-permeable top sheet 22. A liquid-permeable sheet may be disposed in place of the liquid-impermeable sheet 21, so that the diaper absorbs liquid from both the front and back sides.

[0028] A liquid-impermeable sheet 21 is provided on the back side of the absorbent body 23 so as to protrude beyond the periphery of the absorbent body 23. As the liquid-impermeable sheet 21, in addition to polyethylene film or the like, a sheet that has moisture permeability without impairing water-blocking properties can also be used to prevent stuffiness. This water-blocking and moisture-permeable sheet can be a microporous sheet obtained by melt-kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene to form a sheet, and then stretching the sheet in a uniaxial or biaxial direction.

[0029] The outer surface of the liquid-impermeable sheet 21 is covered with an exterior sheet 27 made of nonwoven fabric, and this exterior sheet 27 extends outward from the periphery of the liquid-impermeable sheet 21 by a predetermined extension width. Various types of nonwoven fabric can be used as the exterior sheet 27. The material fibers that make up the nonwoven fabric can include synthetic fibers such as polyolefins such as polyethylene or polypropylene, polyesters, and polyamides, as well as recycled fibers such as rayon or cupra, and natural fibers such as cotton. As shown in the examples of Figures 5 to 7, the exterior sheet can be omitted.

[0030] The front side of the absorbent body 23 is covered with a liquid-permeable top sheet 22. In the illustrated embodiment, the absorbent body 23 partially protrudes from the side edges of the top sheet 22, but the width of the top sheet 22 can be increased so that the side edges of the absorbent body 23 do not protrude. Various types of nonwoven fabrics can be used as the top sheet 22.

[0031] An intermediate sheet 25 is preferably interposed between the top sheet 22 and the absorbent body 23, but is not required. This intermediate sheet 25 is provided to prevent backflow of urine absorbed by the absorbent body 23, and is preferably made of a material with low water retention and high liquid permeability, such as various nonwoven fabrics or mesh films. When the front end of the top sheet 22 is 0% and the rear end of the top sheet 22 is 100%, the front end of the intermediate sheet 25 is preferably located in the range of 0-11%, and the rear end of the intermediate sheet 25 is preferably located in the range of 92-100%. Furthermore, the width W4 of the intermediate sheet 25 is preferably approximately 50-100% of the minimum width W5 of the constricted portion 23n of the absorbent body 23, which will be described later. The intermediate sheet 25 may also be omitted.

[0032] At both ends of the pad-type disposable diaper 200 in the front-to-back direction LD, the liquid-impermeable sheet 21, the outer sheet 27 and the top sheet 22 are bonded together and extend further to the front and rear sides than the front and rear ends of the absorbent body 23, forming end flap portions EF where the absorbent body 23 is not present.

[0033] On both sides of the pad-type disposable diaper 200, the liquid-impermeable sheet 21 and the exterior sheet 27 each extend outward beyond the side edges of the absorbent body 23, and the outer root portions 24x of the gathered sheets 24s forming the three-dimensional gathers 24 in the width direction WD are attached to the inner surface of the portion from this extension to the side portions of the top sheet 22 over the entire length in the front-to-back direction LD, thereby forming side flap portions SF where the absorbent body 23 is not present. These attached portions are indicated by diagonal lines in Fig. 1 and can be formed using a hot melt adhesive, heat sealing, or ultrasonic sealing. When the exterior sheet 27 is not provided, the liquid-impermeable sheet 21 can be extended to the side flap portions SF instead of the exterior sheet 27 to form the outer surfaces of the side flap portions SF.

[0034] The gathered sheet 24s may be made of a plastic sheet or meltblown nonwoven fabric, but in terms of feel to the skin, a nonwoven fabric that has been treated with silicone or the like to be water repellent is preferably used.

[0035] A main portion 24m on the widthwise center side of the gathered sheet 24s extends onto the top sheet 22, and at the end portion on the widthwise center side, elongated gathered elastic members 24G are fixed in a stretched state along the front-to-rear direction with a hot melt adhesive or the like. These gathered elastic members 24G can be made of commonly used materials such as styrene rubber, polyolefin rubber, urethane rubber, ester rubber, polyurethane, polyethylene, polystyrene, styrene butadiene, silicone, polyester, etc., formed in the shape of thread, string, strip, etc.

[0036] Each gathered sheet 24s has a root portion 24x whose outer widthwise ends are bonded to the inner surface of the article (the surface of the top sheet 22 and the inner surface of the exterior sheet 27 in the illustrated embodiment) over the entire front-to-back direction, and a main portion 24m extending from the root portion 24x toward the center in the widthwise direction. Both front-to-back ends of the main portion 24m are fixed to the inner surface of the article (the surface of the top sheet 22 in the illustrated embodiment) to form laid-down portions 24f, and the portion between them is an unfixed portion 24u that is not fixed to the article (the surface of the top sheet 22 in the illustrated embodiment). In the unfolded state, the pair of three-dimensional gathers 24 provided on both sides covers both side ends of the top sheet 22 over the entire front-to-back direction, and the portion between them is exposed to the surface of the article, but in the natural length state and when worn, the unfixed portion 24u of the three-dimensional gathers 24 rises up from the inner surface of the article (the surface of the top sheet 22 in the illustrated embodiment) to form a blocking wall. The starting point 24b of this blocking wall is located at the boundary between the root portion 24x and the main portion 24m of the gathered sheet 24s.

[0037] An example of a pad-type disposable diaper 201 having a different structure of standing gathers 24 is shown in Figures 5 to 7. In this pad-type disposable diaper 201, the top sheet 22 extends from the front side of the absorber 23, past the sides of the absorber 23, to the back side of the absorber 23, and the standing gathers 24 have a root portion 24x fixed to the side of the back surface of the disposable diaper, a main portion 24m extending from the root portion 24x past the sides of the absorber 23 to the side of the top sheet 22, folded-down portions 24f formed by fixing the front and rear ends of the main portion 24m to an article in a folded state, and an unfixed portion 24u formed by leaving the portion of the main portion 24m between the front and rear folded-down portions 24f unfixed to the article. Each portion of the standing gathers 24 is formed by a gathered sheet 24s folded back at the end of the main portion 24m (the edge opposite the root portion 24x) of the standing gathers 24 to form a double layer. Further, between the double gathered sheets 24s, elongated gathered elastic members 24G are fixed along the front-to-rear direction LD at least at the ends of the non-fixed portions 24u.

[0038] Although the three-dimensional gathers 24 in the above-described examples have a configuration in which the main portion 24m is not folded back, any known structure may be employed, such as a structure in which the main portion 24m has a first portion on the root portion 24x side extending toward the widthwise center and a second portion on the end portion side that is folded back at the widthwise center end of the first portion and extends widthwise outward. Also, as in the examples shown in Figures 5 to 7, a structure without side flap portions SF may be achieved by folding back sheets (in the illustrated examples, the top sheet 22, gathered sheet 24s, liquid-impermeable sheet 21, and exterior sheet 27) that are wider than the absorbent body 23 at both side edges of the absorbent body 23 to the opposite side of the absorbent body 23.

[0039] The absorbent body 23 is formed by accumulating pulp fibers, and antibacterial powder particles are dispersed in at least a portion of the absorbent body 23. The absorbent body 23 may have a two-layer structure consisting of a lower layer 23B and an upper layer 23A disposed on its surface, as shown in FIGS. 1 to 4, or a single-layer structure, as shown in FIGS. 5 to 7. When the absorbent body 23 has multiple layers, each layer can be formed separately by accumulating pulp fibers for each layer and then stacked. The term "antibacterial powder particles being held in a portion of the absorbent body 23" includes cases where antibacterial powder particles are held only in a portion of the planar direction, as well as cases where antibacterial powder particles are held in a portion of the thickness direction. Furthermore, the latter case also includes cases where antibacterial powder particles are mixed in only some layers of the absorbent body 23 and other layers do not contain antibacterial powder particles, cases where antibacterial powder particles are contained in only a portion of the thickness direction of a single layer, cases where antibacterial powder particles are held on the surface or back surface of the absorbent body 23 or one of its layers, and cases where antibacterial powder particles are sandwiched between the layers of the absorbent body 23. Furthermore, the absorbent 23 maintaining the antibacterial powder in a dispersed state includes cases where the pulp fibers of the absorbent 23 or its layer and the antibacterial powder are mixed without the use of adhesive (the antibacterial powder penetrates and is captured between the pulp fibers), and the superabsorbent polymer particles and antibacterial powder inside the absorbent 23 or its layer are not adhered to the inside of the absorbent 23 or its layer, cases where antibacterial powder dispersed in a plane is adhered to the front or back surface of the absorbent 23 or its layer, and cases where antibacterial powder dispersed in a plane is sandwiched between the layers of the absorbent 23 with or without the use of adhesive.

[0040] The absorbent body 23 or a layer thereof is preferably formed by accumulating a mixture of pulp fibers and superabsorbent polymer particles (i.e., the superabsorbent polymer particles are held in a dispersed state throughout the absorbent body 23), but the superabsorbent polymer particles may be adhered to the front or back surface of the absorbent body 23 or a layer thereof, the superabsorbent polymer particles may be sandwiched between the layers of the absorbent body 23, or the absorbent body 23 may not contain superabsorbent polymer particles.

[0041] Pulp fibers can be any fibers extracted from wood, grass, or other plants by mechanical and / or chemical processing. Pulp fibers can be made from softwood, hardwood, bamboo, rice, dregs, Japanese pampas grass, hemp, sugarcane, and other materials. Artificial cellulose fibers such as rayon and acetate can also be used. Pulp fibers can be softwood pulp fibers (pulp fibers derived from softwoods) or hardwood pulp fibers (pulp fibers derived from hardwoods), which have a shorter average fiber length than softwood pulp fibers. Either one of these fibers can be used alone, or both can be used in combination. Pulp fibers can also contain regenerated pulp fibers (recycled pulp fibers). For example, the pulp fibers can contain recycled softwood pulp fibers and recycled hardwood pulp fibers.

[0042] In the absorbent body 23 using a mixture of softwood pulp fibers and hardwood pulp fibers, not only are fibers with a relatively long fiber length and a wide fiber width mixed in, but also fibers with a relatively short fiber length and a narrow fiber width, resulting in a higher fiber density than the absorbent body 23 made solely of softwood pulp fibers that has been commonly used in the past. This is particularly preferable in that not only is the liquid retention ability of the fibers improved by capillary action, but also the retention of superabsorbent polymer particles and antibacterial powder particles within the absorbent body 23 (between the pulp fibers) is improved.

[0043] Both the hardwood pulp fibers and the softwood pulp fibers are preferably bleached hardwood kraft pulp (LBKP) and bleached softwood kraft pulp (NBKP) produced by the kraft process, but other types of pulp, such as soda pulp, sulfite pulp, chemi-thermomechanical pulp, chemi-reiner mechanical pulp, and thermo-chemi-mechanical pulp, may also be used.

[0044] When a mixture of softwood pulp fibers and hardwood pulp fibers is used, the content of softwood pulp fibers and hardwood pulp fibers in the total pulp fibers is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 98% by mass or more. It is particularly preferable that all pulp fibers in the absorber 23 consist essentially of softwood pulp fibers and hardwood pulp fibers. The mass ratio of hardwood pulp fibers to other pulp fibers, such as softwood pulp fibers, is not limited and can be, for example, 10 / 90 to 90 / 10. From the viewpoint of operability, however, it is preferably 20 / 80 to 50 / 50, more preferably 25 / 75 to 38 / 62, even more preferably 25 / 75 or more but less than 38 / 62, even more preferably 26 / 74 to 36 / 64, and particularly preferably 28 / 72 to 35 / 65. In this specification, unless otherwise specified, the blending amount of pulp fiber or its material refers to the bone dry internal addition amount, that is, the mass ratio in the bone dry state.

[0045] When hardwood pulp fibers are contained in the absorbent body 23, it is preferable that the proportion of pulp fibers having a fiber length of 0.5 mm or more and less than 1.1 mm be 40% or more by mass, and the proportion of pulp fibers having a fiber width of 10 μm or more and less than 35 μm be 90% or more by mass. The proportion of pulp fibers having a fiber length of 0.5 mm or more and less than 1.1 mm can be preferably 42.6% or more, more preferably 43% or more, and even more preferably 43.2% or more, 43.7% or more, or 45% or more. The proportion of pulp fibers having a fiber width of 10 μm or more and less than 35 μm can be preferably 90.6% or more, more preferably 91.0% or more, and even more preferably 91.2% or more, or 91.4% or more. By having the absorbent body 23 contain specific pulp fiber lengths and specific pulp fiber widths within specific ranges, the benefits of using hardwood pulp fibers are further enhanced. The upper limit of the proportion of pulp fibers with a fiber length of 0.5 mm or more and less than 1.1 mm is not particularly limited, but due to variations in fiber length resulting from the fact that pulp is a natural material, it can be 80 mass % or less, 60 mass % or less, or 55 mass % or less. Similarly, the upper limit of the proportion of pulp fibers with a fiber width of 10 μm or more and less than 35 μm is not particularly limited, but can be 98 mass % or less, 95 mass % or less, or 94 mass % or less.

[0046] The fiber length and fiber width of pulp fibers can be measured using the measuring instrument "VALMET FS5" in accordance with JIS-P8226:2011 (ISO16065-2:2007) "Pulp - Fiber length measurement method by optical automatic analysis method."

[0047] Furthermore, when hardwood pulp fibers are contained in the absorbent body 23, the average fiber length when pulp fibers having a fiber length of 0.5 mm or more and less than 1.1 mm are measured at 0.02 mm intervals (classification width of 0.02 mm) can be 0.5 to 0.8 mm, preferably 0.6 to 0.7 mm. This can suppress variations in the distribution of voids in the absorbent body 23 that can occur depending on the orientation direction of the pulp fibers.

[0048] Furthermore, when hardwood pulp fibers are contained in the absorbent body 23, the standard deviation σ when pulp fibers with a fiber length of 0.5 mm or more but less than 1.1 mm are measured at 0.02 mm intervals (classification width of 0.02 mm) can be 0.58 mm or less, preferably 0.56 mm or less, more preferably 0.54 mm or less, and even more preferably 0.50 mm or less. Having a standard deviation within the above range further enhances the benefits of using hardwood pulp fibers.

[0049] Furthermore, when pulp fibers with a fiber width of 10 μm or more and less than 35 μm are measured at 1 μm intervals (classification width of 1 μm), the average fiber width can be 15 μm or more and 30 μm or less, preferably 18 μm or more and 27 μm or less. By keeping the average fiber width within this range, it is possible to maintain an appropriate amount of interfiber space and prevent a decrease in absorption rate.

[0050] When pulp fibers with a fiber width of 10 μm or more and less than 35 μm are measured at 1 μm intervals (classification width of 1 μm), the standard deviation σ can be 2.9 μm or less, preferably 2.8 μm or less, more preferably 2.75 μm or less, and even more preferably 2.6 μm or less, 2.59 μm or less. By keeping the standard deviation within the above range, the advantages of using hardwood pulp fibers are further enhanced.

[0051] When absorbent body 23 has multiple layers, only some of them may contain hardwood pulp fibers, or all of them may contain hardwood pulp fibers. For example, when absorbent body 23 has a two-layer structure consisting of upper layer 23A and lower layer 23B, only lower layer 23B may contain hardwood pulp fibers, or only upper layer 23A may contain hardwood pulp fibers.

[0052] The term "superabsorbent polymer particles" includes not only "particles" but also "powder." The superabsorbent polymer particles used in this type of disposable diaper can be used as they are. The pre-swelling particle size (particle size before absorbing liquid) of the superabsorbent polymer particles is not particularly limited, but the average particle size is preferably within the range of 250 to 500 μm. Furthermore, it is preferable that the total amount of superabsorbent polymer particles have a pre-swelling particle size of more than 150 μm and not more than 850 μm, more preferably 70% by mass or more, and particularly preferably 80% by mass or more. Furthermore, when hardwood pulp fibers are used, it is preferable that the total amount of superabsorbent polymer particles have a pre-swelling particle size shorter than the average fiber length (for example, not more than 600 μm, more preferably not more than 500 μm). It is more preferable that the total amount of superabsorbent polymer particles have a pre-swelling particle size shorter than the average fiber length (for example, not more than 600 μm, more preferably not more than 500 μm).

[0053] The material of the superabsorbent polymer particles is not particularly limited, but a water absorption capacity of 40 g / g or more is preferred. Examples of superabsorbent polymer particles include starch-based, cellulose-based, and synthetic polymer-based (polyacrylate-based, polysulfonate-based, maleic anhydride-based) superabsorbent polymer particles, such as starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, crosslinked sodium carboxymethylcellulose, and acrylic acid (salt) polymers. The shape of the superabsorbent polymer particles is preferably a commonly used powder or granular form, but other shapes can also be used.

[0054] The highly absorbent polymer particles preferably have a water absorption rate of 70 seconds or less, particularly 40 seconds or less. If the water absorption rate is too slow, backflow (liquid supplied into the absorber 23 flows back out of the absorber 23) is likely to occur.

[0055] Furthermore, the highly absorbent polymer particles preferably have a gel strength of at least 1000 Pa. This effectively prevents the sticky feeling after absorbing liquid, even when the absorbent body 23 is bulky.

[0056] The ratio of pulp fibers to superabsorbent polymer particles in the layer containing superabsorbent polymer particles (the entire absorbent body 23 in the case of a single layer) is not particularly limited, and for example, the weight ratio of pulp fibers to superabsorbent polymer particles can be 9:1 to 1:9, and it is particularly preferable that it be 2:1 to 1:2.

[0057] The content of superabsorbent polymer particles in a layer containing superabsorbent polymer particles may vary in at least one of the thickness direction, the front-rear direction LD, and the width direction WD, as long as the superabsorbent polymer particles are dispersed and mixed within the layer. For example, the content of superabsorbent polymer particles in a layer containing superabsorbent polymer particles may increase or decrease continuously or stepwise from the middle portion to both sides in at least one of the thickness direction, the front-rear direction LD, and the width direction WD.

[0058] The antibacterial powder contains more than 0% and less than 50% by weight of an inorganic antibacterial agent. The content of the inorganic antibacterial agent in the antibacterial powder is more preferably 0 to 20% by weight, and particularly preferably 0 to 10% by weight.

[0059] Suitable inorganic antibacterial agents include one or more selected from antibacterial metals such as silver, copper, zinc, nickel, and zirconium, as well as metal-supported antibacterial materials in which these metals, their ions, oxides, or compounds are supported on an inorganic carrier. The carrier for the metal-supported antibacterial material is not particularly limited, and suitable carriers include, for example, silicate-based materials such as zeolite (aluminosilicate), magnesium aluminometasilicate, and calcium silicate; phosphate-based materials such as zirconium phosphate and calcium phosphate double salt; oxide-based materials such as silica, silica gel, zinc oxide, and alkaline earth metal (hydroxide) oxides; glass-based materials such as soluble glass and composite glass; and potassium titanate. Inorganic antibacterial agents can be used in any form, including non-viscous liquids, viscous liquids, and powders, as long as they can be incorporated into the antibacterial powders and granules.

[0060] Inorganic antibacterial agents are particularly suitable that elute antibacterial metal ions upon contact with the moisture in excrement. More specifically, inorganic antibacterial agents are preferred in which cations such as silver ions are supported by an ion exchange reaction on an inorganic ion exchanger with cation exchange capacity, such as zeolite, zirconium phosphate, or potassium titanate. An example of a commercially available inorganic antibacterial agent in which silver ions are supported on zeolite is "Zeomic (registered trademark)" from Sinanen Zeomic Co., Ltd. Another preferred inorganic antibacterial particle is one in which an antibacterial metal, an oxide of such a metal, or a compound of such a metal is mechanically supported on hydroxyapatite, calcium silicate, calcium phosphate, or the like. An example of a commercially available inorganic antibacterial agent in which a silver compound is supported on calcium phosphate is "Amtec Clean Z" from Amtec Co., Ltd.

[0061] In order to ensure that the content of the inorganic antibacterial agent in the antibacterial powder and granules falls within the aforementioned range, the antibacterial powder and granules are preferably granulated with a bulking agent. Known bulking agents can be used, and inactive powders and granules are preferred, but active powders and granules may also be used as long as they do not inhibit the antibacterial activity. Examples of known bulking agents include mineral powders and granules such as clay (including kaolin and sericite), talc, bentonite, silica sand, silica stone, calcium carbonate, zeolite, perlite, and vermiculite, as well as vegetable powders and granules such as lactose and sugars including starch. One or more of these known bulking agents can be selected and used.

[0062] When the antibacterial powder is made into granules containing an inorganic antibacterial agent, it may contain a binder (binding agent) to bind the raw materials. For example, the antibacterial powder can be granulated by binding inorganic antibacterial agents together, bulking agents together, or an inorganic antibacterial agent and a bulking agent together with a binder. The binder also has a bulking effect, so it also serves as a bulking agent. In other words, in the case of a bulking agent that has adhesiveness (binding properties) and also functions as a binder, such as bentonite, a binder may not be used, but it can be used regardless of the adhesiveness of the bulking agent. Furthermore, when the antibacterial powder is made into a compression-molded product such as a pellet, a binder may not be used, but may be used.

[0063] Although hydrophilic binders are preferred as binders, hydrophobic binders may also be used as long as they exert their antibacterial properties upon contact with the moisture in excrement (i.e., in the case of inorganic antibacterial agents that exert their antibacterial properties through metal ions, the metal ions can be eluted into the moisture in excrement). Hydrophilic binders include those that are water-soluble and water-swellable, and those that are water-soluble and organic solvent-soluble. Either can be used, but those that do not disintegrate or are resistant to dissolution or swelling due to the moisture in excrement are preferred. Furthermore, when using inorganic antibacterial agents that elute metal ions such as silver ions, even if a binder is used for granulation, it is preferable that the solidified binder be permeable to moisture and metal ions, regardless of whether it swells with the moisture in excrement.

[0064] Examples of hydrophilic binders that are water-soluble and water-swellable include natural substances such as sugars including starch, rubbers, gums, and proteins; semi-synthetic substances such as carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxyethyl cellulose (HEC), sodium lignosulfonate, calcium lignosulfonate, carboxymethyl starch (CMS), hydroxyethyl starch, and sodium starch phosphate; vinyl polymers such as polyvinyl alcohol (PVA), polyvinyl methyl ether (PVM), and polyvinyl acetate; and synthetic substances such as polyacrylic acid amide, sodium polyacrylate, and other water-soluble copolymers.

[0065] Examples of water-soluble and organic solvent-soluble surfactants include semi-synthetic substances such as hydroxypropyl cellulose (HPC) and hydroxypropyl methylcellulose, synthetic substances such as polyethylene glycol (PEG), polyethylene oxide, polyvinylpyrrolidone (PVP) and vinylpyrrolidone-vinyl acetate copolymer, and surfactants such as nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants.

[0066] Examples of hydrophobic binders include natural substances such as animal and vegetable oils and liquid paraffin, semi-synthetic substances such as ethyl cellulose (EC), acetyl cellulose and ester gum, and synthetic substances such as polyvinyl acetate, coumarone resin, petroleum resin and phenol resin.

[0067] The granulation procedure for the antibacterial powder granules is not particularly limited, and any known granulation method such as tumbling granulation, fluidized bed granulation, extrusion granulation, extrusion molding, compression granulation, compression molding, crushing granulation, stirring granulation, or coating granulation can be appropriately adopted, taking into consideration the distribution of the inorganic antibacterial agent inside the antibacterial powder granules and the properties of the granulation raw materials.

[0068] It is preferable that the antibacterial powder and granules are made porous by selecting the amount of filler and binder used and the granulation operation, but they may also be non-porous as long as the antibacterial action of the inorganic antibacterial agent is exerted.

[0069] The inorganic antibacterial agent may be distributed in any manner within the antibacterial powder granules as long as the antibacterial effect of the inorganic antibacterial agent is exhibited. For example, the inorganic antibacterial agent may be uniformly dispersed throughout the antibacterial powder granules, or the content of the inorganic antibacterial agent may decrease stepwise or continuously toward the outer surface. Alternatively, as shown in Figure 8(a), substantially the entire outer surface of the antibacterial powder granules 30 may be covered with coatings 32, 33 made of at least one of an extender 32 and a binder 33 that do not contain inorganic antibacterial agent 31, and only the inner core portions 31, 32, 33 may contain the inorganic antibacterial agent 31 uniformly dispersed therein.

[0070] For example, as shown in Figures 8(b) and 8(c), the antibacterial powder 30 preferably has a distribution in which the content of the inorganic antibacterial agent 31 increases continuously (Figure 8(b)) or stepwise (Figure 8(c)) toward the outer surface, which allows the inorganic antibacterial agent 31 to come into contact with the moisture in excrement more easily, thereby enhancing the antibacterial effect. In this case, the inorganic antibacterial agent 31 may be dispersed throughout the antibacterial powder 30 as shown in Figure 8(b). However, as shown in Figure 8(c), it is preferable to have the inorganic antibacterial agent 31 absent from the core portion 34 and contained only in the outer shell portion that entirely covers the core portion 34, as this allows for particularly reduced amounts of inorganic antibacterial agent 31 to be used. In this case, the core portion 34 can be granulated using only a bulking agent or a bulking agent and a binder. The outer shell portion can be formed from at least one of a bulking agent 32 and a binder 33.

[0071] Regardless of the distribution, it is particularly preferable for the antibacterial powder granules to have an inorganic antibacterial agent exposed on the outer surface. That is, when the solidified binder body is permeable to moisture and metal ions, the antibacterial effect can be sufficiently exhibited even if the antibacterial powder granules do not have an inorganic antibacterial agent exposed on the outer surface, and this can be said to be more preferable in terms of the strength of the antibacterial powder granules, but it is more preferable in terms of the antibacterial effect to have an inorganic antibacterial agent exposed on the outer surface.

[0072] The average particle size of the antibacterial powder granules is preferably within the range of 250 to 500 μm. Therefore, when a powdered inorganic antibacterial agent is used, its average particle size must be smaller than that of the antibacterial powder granules. The average particle size of the inorganic antibacterial agent is preferably 0.2 to 3.0 times, particularly 0.5 to 2.0 times, the average particle size of the antibacterial powder granules. Thus, by dispersing the inorganic antibacterial agent in the absorbent body 23 as a powder granule with a sufficiently large particle size and a relatively low content of inorganic antibacterial agent, rather than as is, the inorganic antibacterial agent can be improved in terms of the amount of inorganic antibacterial agent used. In particular, when the antibacterial powder granules are dispersed and held within the absorbent body 23 or its layer by mixing the antibacterial powder granules with the pulp fibers of the absorbent body 23 or its layer, the antibacterial powder granules are trapped between the pulp fibers without being fixed with an adhesive or the like, thereby improving the retention of the inorganic antibacterial agent. In absorbents made by mixing and accumulating pulp fibers and superabsorbent polymer particles, the average particle size of the superabsorbent polymer particles is generally within the range of 250 to 500 μm, and antibacterial powder and granules of a similar average particle size will have the same good retention properties within the absorbent 23 as the superabsorbent polymer particles in typical absorbents.

[0073] The particle size of the antibacterial powder is not particularly limited, but particles with a particle size of more than 150 μm and not more than 850 μm preferably account for 60 mass % or more of the total, more preferably 70 mass % or more, and particularly preferably 80 mass % or more. Furthermore, when hardwood pulp fibers are used, antibacterial powder with a particle size shorter than the average fiber length (for example, not more than 600 μm, more preferably not more than 500 μm) preferably accounts for 60 mass % or more of the total, more preferably 70 mass % or more, and particularly preferably 80 mass % or more.

[0074] The particle size distribution of superabsorbent polymer particles, antibacterial powders, and inorganic antibacterial agents can be determined by placing standard sieves (e.g., Tokyo Screen standard sieves) with openings of 850 μm, 600 μm, 500 μm, 355 μm, 300 μm, 250 μm, and 150 μm as specified in JIS Z 8801, and a tray in this order, starting from the top, in a shaker (e.g., Retsch AS200). The entire amount of particles is then loaded onto the top sieve and sieved. The shaking conditions are 50 Hz, amplitude 0.5 mm, and shaking time 10 minutes. Sieving is performed at a temperature of 23 ± 2°C and humidity of 50 ± 5%, and the samples are allowed to stand in the same environment for at least 24 hours before measurement. Sieving is performed three times, and the average of the three measurements is used as the sieved mass for each sieve. From the mass of the particles on each sieve and the total mass (mass of all particles), the content ratio (mass percentage) of the particle size ranges corresponding to each sieve (i.e., over 850 μm, over 600 μm and up to 850 μm, over 500 μm and up to 600 μm, over 355 μm and up to 500 μm, over 300 μm and up to 355 μm, over 250 μm and up to 300 μm, over 150 μm and up to 250 μm, and up to 150 μm) can be determined. The average particle size is the particle size corresponding to the median cumulative value (50%) of the particle size cumulative curve determined based on this particle size distribution.

[0075] In particular, if the average particle size of the superabsorbent polymer particles before swelling is 250 to 500 μm and the average particle size of the antibacterial powder is 0.2 to 3.0 times the average particle size of the superabsorbent polymer particles, the sizes of the superabsorbent polymer particles and antibacterial powder mixed into the pulp fibers will be the same or close to each other, and when the pulp fibers, superabsorbent polymer particles, and antibacterial powder are accumulated in a mixed state to manufacture the absorbent body 23, the superabsorbent polymer particles and antibacterial powder can be more uniformly dispersed and mixed within the absorbent body 23, and not only the retention of the antibacterial powder within the absorbent body 23 but also the retention of the superabsorbent polymer particles will be improved. In manufacturing the absorbent body 23, a well-known absorbent body 23 manufacturing device (fiber stacking drum) is used, and the antibacterial powder particles are supplied separately from the superabsorbent polymer particles in a supplying method similar to the well-known method for supplying superabsorbent polymer particles, or a mixture of superabsorbent polymer particles and antibacterial powder particles is supplied, thereby manufacturing an absorbent body 23 in which pulp fibers, superabsorbent polymer particles, and antibacterial powder particles containing an inorganic antibacterial agent are mixed and accumulated.

[0076] The basis weight of the pulp fiber in the layer containing the antibacterial powder and granules (the entire absorbent body 23 in the case of a single layer) can be determined appropriately depending on the product application. For example, it is 100 to 500 g / m 2 , preferably 100 to 300 g / m 2 , particularly preferably 120 to 250 g / m 2 For example, in the case of disposable diapers, the weight of the pulp fiber can be 100 to 300 g / m 2 , preferably 120 to 200 g / m 2 In the case of a sanitary napkin, the weight of the pulp fiber can be 150 to 500 g / m 2 , preferably 250 to 400 g / m 2 The basis weight of the pulp fibers may be uniform throughout, or may have areas with relatively high or low basis weight. The thickness of the layer containing the antibacterial powder and granules can be determined as appropriate, but may be, for example, about 1.0 to 20.0 mm, particularly about 1.0 to 5.0 mm.

[0077] The ratio of pulp fiber to antibacterial powder in the layer containing antibacterial powder is not particularly limited, and can be, for example, a weight ratio of pulp fiber to antibacterial powder of 20:1 to 2:1, and preferably 20:1 to 5:1.

[0078] When the absorbent body 23 has a plurality of layers as in the illustrated example, the type of antibacterial powder granules contained in one layer may be different from the type of antibacterial powder granules contained in another layer.

[0079] The antibacterial powder content of the layer containing antibacterial powder may vary in at least one of the thickness direction, the front-to-rear direction (LD), and the width direction (WD), as long as the antibacterial powder is dispersed and mixed within the layer. For example, the antibacterial powder content of the layer containing antibacterial powder may increase or decrease continuously or stepwise from the middle portion to both sides in at least one of the thickness direction, the front-to-rear direction (LD), and the width direction (WD). If the layer containing antibacterial powder contains superabsorbent polymer particles, the antibacterial powder may be distributed in the same manner as the superabsorbent polymer particles.

[0080] Furthermore, when the absorbent body 23 has multiple layers as in the illustrated example, there may be layers containing antibacterial powder granules and layers not containing antibacterial powder granules, and the amount of antibacterial powder granules contained in one layer may be greater than the amount of antibacterial powder granules contained in another layer. Furthermore, when the absorbent body 23 has layers containing antibacterial powder granules and layers not containing antibacterial powder granules, the layers containing antibacterial powder granules may contain hardwood pulp fibers, and the layers not containing antibacterial powder granules may not contain hardwood pulp fibers.

[0081] In particular, as shown in the illustrated example, the absorbent article has a pair of three-dimensional gathers 24 that cover both side edges of the top sheet 22 over the entire front-to-back direction LD in the unfolded state, and when worn, the central portion of the three-dimensional gathers 24 rises from the top sheet 22 in the front-to-back direction LD to form a barrier. The absorbent body 23 has a two-layer structure consisting of an upper layer 23A and a lower layer 23B. When both side edges of the upper layer 23A are located between the pair of three-dimensional gathers 24 in the unfolded state, W6, it is preferable that the upper layer 23A contains antibacterial powder granules and the lower layer 23B does not. In an absorbent article with three-dimensional gathers 24 as shown in the illustrated example, the portion of the top sheet 22 located between the three-dimensional gathers 24, W6, is the area that mainly comes into contact with the skin. Therefore, providing an absorbent body 23 with an upper layer 23A narrower than the width W6 between the pair of three-dimensional gathers 24 as in this embodiment and incorporating antibacterial powder granules only in the upper layer 23A allows the antibacterial powder granules to be located only on the back side of the area that mainly comes into contact with the skin, which is preferable because it is cost-effective.

[0082] Conversely, there is another advantage when the lower layer 23B contains antibacterial powder granules and the upper layer 23A does not contain antibacterial powder granules. That is, this is the case when the main objective is not to provide antibacterial properties near the surface that comes into contact with the skin, but to suppress odor generation inside the absorbent body 23. In such a case, by intentionally providing antibacterial powder granules only in the lower layer 23B, there is an advantage that the antibacterial powder granules are less likely to escape through the top sheet 22 in the area that mainly comes into contact with the skin.

[0083] The absorbent body 23 can be wrapped, either integrally or individually, in a liquid-permeable and liquid-retentive wrapping sheet 26 as needed to maintain the shape and retain the superabsorbent polymer particles. As the wrapping sheet 26, crepe paper or a nonwoven fabric having one or more spunbond layers and one or more meltblown layers (such as an SMS nonwoven fabric or an SMMS nonwoven fabric) can be suitably used to block the movement of the superabsorbent polymer particles and antibacterial powder granules.

[0084] The absorbent body 23 extends from the front portion F2 to the rear portion B2. In the case of a two-layer absorbent body 23 having an upper layer 23A and a lower layer 23B, the upper layer 23A can have the same dimensions as the lower layer 23B, but as in the illustrated embodiment, it is desirable that the overall length and width of the upper layer 23A be shorter than those of the lower layer 23B. Typically, the overall length of the upper layer 23A can be about 60 to 90% of the overall length of the lower layer 23B, and the overall width of the upper layer 23A can be about 30 to 90% of the overall width of the lower layer 23B.

[0085] The shapes of the upper layer 23A and the lower layer 23B can be determined as appropriate, and each can be rectangular. However, it is preferable that at least the larger of the two layers (lower layer 23B in the illustrated example) has a narrow constricted portion 23n formed in a predetermined central portion in the front-to-rear direction, including the crotch area C2. The minimum width W5 of this constricted portion 23n is preferably approximately 50-65% of the width W2 of the non-constricted portions located before and after the constricted portion 23n. Furthermore, when the front end of the article is 0% and the rear end of the article is 100%, the front end of the constricted portion 23n is preferably located within a range of 10-25%, the rear end of the constricted portion 23n is preferably located within a range of 40-65%, and the portion of the constricted portion 23n with minimum width W5 (minimum width portion) is preferably located within a range of 25-30%.

[0086] <Test example> Test pieces Nos. 1 to 5 described below were prepared and subjected to antibacterial tests as described below. (Creating test specimens) Nine square test pieces were prepared for each of test pieces No. 1 to No. 4, each having the following layers 1 to 10 from top to bottom. Test piece No. 5 was used as a standard fabric (control) for antibacterial testing. The dimensions of each test piece and each layer were 22 mm long x 22 mm wide. (1st layer) Top sheet simulation layer (fiber: PE (sheath) / PET (core), fineness: 2.2 dtex, basis weight: 21 g / m 2 , Type: Air-through nonwoven fabric). (Second layer) Intermediate sheet simulation layer (fiber: PE (sheath) / PP (core), fineness: 4.4 dtex, basis weight: 22 g / m 2 , Type: Spunbond nonwoven fabric). (3rd layer) Hot melt adhesive layer (application pattern: spiral, basis weight: 5 g / m 2 ). (4th layer) Crepe paper (basis weight 13.5g / m 2 ). (5th layer) Hot melt adhesive layer (application pattern: spiral, basis weight: 5 g / m 2 ). (6th layer) Absorber simulation layer. (7th layer) Absorber simulation layer. (8th layer) Hot melt adhesive layer (application pattern: spiral, basis weight: 5 g / m 2 ). (9th layer) Crepe paper (13.5g / m 2 ). (10th layer) Hot melt adhesive layer (application pattern: spiral, basis weight: 5 g / m 2 ). (11th layer) Breathable porous polyethylene sheet (18g / m 2 ).

[0087] Each absorber-simulating layer had the following first to tenth layers from top to bottom. (1st layer) Pulp sheet (basis weight: 74 g / m 2 ). (Second layer) A layer of a uniform mixture of highly absorbent polymer particles and antibacterial powder granules. (3rd layer) Pulp sheet (basis weight: 74g / m 2 ). (4th layer) A layer of a uniform mixture of highly absorbent polymer particles and antibacterial powder granules. (5th layer) Pulp sheet (basis weight: 74g / m 2 ). (6th layer) A layer of a uniform mixture of highly absorbent polymer particles and antibacterial powder granules. (7th layer) Pulp sheet (basis weight: 74 g / m 2 ). In all of the test pieces Nos. 1 to 4, the same superabsorbent polymer particles (average particle size: 350 μm) were used in the same total content (32 mg per layer). Furthermore, for all of test pieces No. 1 to 4, as shown in Fig. 8(a), antibacterial powder granules (average particle size 350 µm) were used in which substantially the entire outer surface of the antibacterial powder granules 30 was covered with coatings 32, 33 consisting of at least one of an extender 32 and a binder 33 that did not contain an inorganic antibacterial agent 31, and the inorganic antibacterial agent 31 was uniformly dispersed only in the inner core portions 31, 32, 33. The inorganic antibacterial agent was "Amtec Clean Z" (silver compound-supported calcium phosphate and zinc oxide) manufactured by Amtec Corporation, the extender was talc, and the binder was polyvinyl alcohol. However, for the antibacterial powder used in test piece No. 1, the amounts of filler and binder were adjusted so that the inorganic antibacterial agent content was 0.60 wt%. For the antibacterial powder used in test piece No. 2, the amounts of filler and binder were adjusted so that the inorganic antibacterial agent content was 0.30 wt%. For the antibacterial powder used in test piece No. 3, the amounts of filler and binder were adjusted so that the inorganic antibacterial agent content was 0.12 wt%. For the antibacterial powder used in test piece No. 4, the amounts of filler and binder were adjusted so that the inorganic antibacterial agent content was 0.06 wt%. The total basis weight of the antibacterial powder and granules in test piece No. 1 was set to 9.7 g / m so that the content of the inorganic antibacterial agent in all test pieces No. 1 to 4 was 0.47 mg. 2 (The basis weight of each mixture layer is 1 / 6 of this. The same applies below.) The total basis weight of the antibacterial powder and granules in test piece No. 2 was 19.4 g / m 2 The total weight of the antibacterial powder and granules in test piece No. 3 was 48.3 g / m 2 The total weight of the antibacterial powder and granules in test piece No. 4 was 96.6 g / m 2 It was decided.

[0088] (Test Method) The test was conducted as described below in accordance with the bacterial liquid absorption method of JIS L 1902:2015 "Antibacterial test method and antibacterial effect of textile products." (Sample preparation) Nine samples were prepared for each test piece by placing the test piece in a sterilized container. (Preparation of test bacterial solution) The test bacteria (Proteus mirabilis) was inoculated onto soybean casein digest agar medium and cultured at 37°C for 24 hours. The nutrient medium was diluted 20 times with sterilized water and 0.05% Tween 80 was added. Using these, the viable count of the test bacteria was 10 6 The test bacterial solution was prepared to have a concentration of approximately CFU / mol. (Inoculation and cultivation of test bacterial solution) The sample was inoculated with 10 ml of test bacterial solution and cultured at 37°C ± 2°C for 8 hours. (Measurement of viable bacteria count) Immediately after incubation, and after 4 and 8 hours, three samples from each test piece were counted for viable bacterial counts as follows, and the average was recorded as the viable bacterial count. Specifically, each sample was washed out with 20 ml of soybean-casein-digest liquid medium supplemented with lecithin and polysorbate 80, and a 10-fold dilution series was prepared with physiological saline to prepare the test solutions. These test solutions were then poured onto standard agar medium and incubated at 35°C for 48 hours. After incubation, the formed colonies were counted to calculate the viable bacterial count. The test results are shown in Table 1 and a graph in Figure 9.

[0089] [Table 1]

[0090] As is clear from Table 1 and Figure 9, it was found that the increase in the number of viable bacteria can be further suppressed by increasing the content of antibacterial powder granules without increasing the total amount of inorganic antibacterial agent used (in other words, by adding more antibacterial powder granules with a lower content of inorganic antibacterial agent).

[0091] <Explanation of terms used in the specification> When used in this specification, the following terms have the following meanings unless otherwise specified in the specification. "Front-rear direction" refers to the direction indicated by the symbol LD in the drawing (longitudinal direction), and "width direction" refers to the direction indicated by the symbol WD in the drawing (left-right direction), with the front-rear direction and width direction being perpendicular to each other. In the manufacturing process, "MD (machine direction or line direction)" and "CD (cross direction perpendicular to MD)" refer to the "MD" and "CD" directions of the manufacturing equipment, one of which corresponds to the front-to-back direction and the other to the width direction. Furthermore, the MD direction in the product refers to the fiber orientation direction of the nonwoven fabric. Fiber orientation is the direction in which the fibers of the nonwoven fabric run. For example, this can be determined using a measurement method based on the TAPPI standard method T481, which tests for fiber orientation using zero-distance tensile strength, or a simplified measurement method that determines the fiber orientation direction from the ratio of the tensile strengths in the front-to-back and width directions. In the illustrated configuration, the front-to-back direction corresponds to the MD direction and the width direction corresponds to the CD direction, as in most disposable diaper products. "Deployed state" means a flat, deployed state without contraction (including any contraction, such as contraction due to elastic members) or slack. "Elongation rate" refers to the value when the natural length is 100%. For example, an elongation rate of 200% is equivalent to an elongation ratio of 2 times. "Basis weight" is measured as follows: After pre-drying the sample or test piece, leave it in a test room or device under standard conditions (test location: temperature 23±1°C, relative humidity 50±2%) until it reaches a constant weight. Pre-drying refers to bringing the sample or test piece to a constant weight in an environment at a temperature of 100°C. Note that pre-drying is not necessary for fibers with an official moisture regain of 0.0%. From the test piece that has reached a constant weight, use a sample collection template (100mm x 100mm) to cut out a sample measuring 100mm x 100mm. Measure the weight of the sample and multiply it by 100 to calculate the weight per square meter, which is the basis weight. The "thickness" of a sheet that has been embossed or otherwise shaped refers to its "apparent thickness," and is measured using the following method. Specifically, a measurement piece measuring 30 mm long x 30 mm wide is cut out. A cross section passing through the measurement area is created. For example, when measuring the apparent thickness of a sheet with through-holes penetrating the thickness direction, a cross section parallel to the MD is created that does not pass through the through-holes or their peripheral edges. An enlarged photograph of this cross section is then taken using a Keyence VHX-1000 digital microscope or similar, and the apparent thickness of the target portion of the sheet is measured based on this enlarged photograph. To determine the maximum and minimum values, measurements are taken at 10 or more points, and the maximum and minimum values ​​are determined. The "thickness" of the absorber is measured using a thickness measuring device (Peacock, large dial thickness gauge, model JB (measurement range 0-35 mm) or model K-4 (measurement range 0-50 mm)) manufactured by Ozaki Seisakusho Co., Ltd., with the sample and thickness measuring device positioned horizontally. *The "thickness" other than the above was measured using an automatic thickness measuring device (KES-G5 handy compression measurement program) with a load of 0.098 N / cm 2 , and pressure area: 2cm 2 Automatic measurement is performed under the following conditions. The water absorption capacity is measured according to JIS K7223-1996 "Test method for water absorption capacity of superabsorbent resins." The water absorption rate is the "time to the end point" when 2g of superabsorbent polymer and 50g of physiological saline are used and the test is carried out in accordance with JIS K7224-1996 "Test method for water absorption rate of superabsorbent polymers." "Artificial urine" is a mixture of 2 wt% urea, 0.8 wt% sodium chloride, 0.03 wt% calcium chloride dihydrate, 0.08 wt% magnesium sulfate heptahydrate, and 97.09 wt% ion-exchanged water, and is used at a temperature of 37°C unless otherwise specified. If no environmental conditions are specified for a test or measurement, the test or measurement shall be carried out in a test room or device under standard conditions (temperature 23±1°C, relative humidity 50±2%). Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state, not in the natural length state. [Industrial Applicability]

[0092] The present invention can be used for a variety of types of disposable diapers, including not only pad-type disposable diapers such as those in the above example, but also tape-type disposable diapers, pants-type disposable diapers, and other absorbent articles other than disposable diapers, such as sanitary napkins. [Explanation of symbols]

[0093] 21...liquid-impermeable sheet, 22...top sheet, 23...absorbent body, 23A...upper layer, 23B...lower layer, 24...three-dimensional gathers, 24s...gathered sheet, 25...intermediate sheet, 26...packaging sheet, 27...exterior sheet, 30...antibacterial powder and granules, 31...inorganic antibacterial agent, 32...bulking agent, 33...binder, 200, 201...pad-type disposable diaper, B2...rear portion, C2...crotch portion, F2...front portion, LD...front-to-back direction, WD...width direction.

Claims

1. The absorbent body has an absorbent body and a top sheet that covers the front side of the absorbent body, The absorbent article is an absorbent article in which the absorbent body is formed by accumulating pulp fibers, Antibacterial powder particles are dispersed and held in at least a portion of the absorbent body, The antibacterial powder contains more than 0% by weight and less than 50% by weight of an inorganic antibacterial agent, The average particle size of the antibacterial powder and granules is 250 to 500 μm. An absorbent article characterized by:

2. The absorbent body is formed by accumulating pulp fibers, highly absorbent polymer particles, and the antibacterial powder and granules in a mixed state, The highly absorbent polymer particles and the antibacterial powder particles in the absorbent body are not adhered to the inside of the absorbent body, The average particle size of the superabsorbent polymer particles before swelling is 250 to 500 μm, The average particle size of the antibacterial powder granules is 0.2 to 3.0 times the average particle size of the superabsorbent polymer particles. The absorbent article of claim 1.

3. The basis weight of the pulp fiber in the absorbent body is 70 to 700 g / m ２ and the weight ratio of pulp fibers to superabsorbent polymer particles in the absorbent body is 9:1 to 3:7; The weight ratio of pulp fiber to antibacterial powder and granules in the absorbent body is 20:1 to 2:

1. The absorbent article according to claim 2.

4. The inorganic antibacterial agent elutes antibacterial metal ions upon contact with water in excrement, the antibacterial powder and granules contain a bulking agent and are granules obtained by binding the inorganic antibacterial agents together, the bulking agents together, and the inorganic antibacterial agents and the bulking agent together with a binder; the solidified body of the binder is permeable to the moisture and the metal ions; The absorbent article according to any one of claims 1 to 3.

5. The antibacterial powder / granule has a content of the inorganic antibacterial agent that increases stepwise or continuously toward the outer surface. The absorbent article according to claim 4.

6. The antibacterial powder and granules have the inorganic antibacterial agent exposed on the outer surface. The absorbent article according to claim 4 or 5.

7. a pair of three-dimensional gathers that cover both side edges of the top sheet in the entire front-to-rear direction in an unfolded state; When worn, the three-dimensional gathers have a front-to-back middle portion that rises up from the top sheet to form a barrier, The absorbent body has a two-layer structure consisting of an upper layer and a lower layer, In the unfolded state, both side edges of the upper layer are located between the pair of three-dimensional gathers, the upper layer comprises the antimicrobial granules; The lower layer does not contain the antimicrobial granules. The absorbent article according to any one of claims 1 to 3.

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