JP7514647B2 - Absorbent bodies and absorbent articles - Google Patents

Description

The present invention relates to an absorbent body and an absorbent article including the absorbent body.

Generally, absorbent articles are provided with a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between them. Urine and other body fluids pass through the top sheet and are absorbed by the absorbent body. There are various types of absorbent articles for adults and infants, depending on the intended use, such as tape-type disposable diapers, pants-type disposable diapers, urine pads, and light incontinence pads.

Fluff pulp and super absorbent polymer (hereinafter also referred to as "SAP") are generally used together as the absorbent in absorbent articles. On the other hand, various types of super absorbent sheets (hereinafter also referred to as "SAP sheets") consisting of a nonwoven fabric base and a super absorbent polymer have been proposed as alternative absorbents, aiming to further improve wearing comfort, appearance, feel, and urine backflow prevention.

Patent Document 1 discloses a highly absorbent sheet comprising first and second sheets, each having an adhesive-coated surface on one side, and a plurality of SAP layers arranged in stripes extending in the longitudinal direction between the adhesive-coated surfaces of the first and second sheets, in which adhesive is intermittently applied to the area of the adhesive-coated surface of the second sheet facing the SAP layer, and adhesive is continuously applied in the longitudinal direction to the adhesive-coated surfaces of the first and second sheets that directly face the SAP layer on both sides of the width of the SAP layer without an intervening SAP layer.

Patent Document 2 discloses a highly absorbent sheet of a predetermined structure, which includes a first and a second absorbent body that are arranged on one side and the other side of the width direction between a top sheet and a back sheet, respectively, and that contains SAP, the first and second absorbent bodies being made of two sheets of nonwoven fabric with SAP arranged therebetween, the first and second absorbent bodies having first and second folds that extend in the longitudinal direction, respectively, and the first and second folds facing each other.

JP 2006-158676 A JP 2013-042882 A

The highly absorbent sheets of Patent Document 1 and many others use a hot melt adhesive to fix the nonwoven fabric and the highly absorbent polymer, which makes them hard to the touch, resulting in poor comfort when worn, and also causes discomfort due to a lack of fit. In addition, compared to conventional absorbents made of fluff pulp and highly absorbent polymer, most highly absorbent sheets have the highly absorbent polymer fixed to the nonwoven fabric by an adhesive means, and the highly absorbent polymer is present at a high density, which means that absorption takes time and the diffusion of bodily fluids is poor, making them not fully satisfactory in terms of absorbency.

Although the highly absorbent sheet of Patent Document 2 improves the fit to the crotch area due to the above-mentioned structure, the problem of the hard feel that is characteristic of highly absorbent sheets remains unresolved, and therefore does not improve the wearing comfort of absorbent articles. Furthermore, like the highly absorbent sheet of Patent Document 1, the highly absorbent sheet of Patent Document 2 is not fully satisfactory in terms of absorbency.
As described above, the absorbent articles having the highly absorbent sheets of Patent Document 1 and Patent Document 2 as an absorbent body do not have both high levels of absorbency and wearing comfort.

The object of the present invention is to provide an absorbent body that does not lose its absorption rate when repeatedly absorbing body fluids, has excellent body fluid diffusion properties, and has good absorbency and comfort when worn, and an absorbent article that includes the absorbent body.

The present inventors have conducted extensive research to solve the above problems. As a result, the present inventors have discovered that by using a superabsorbent sheet containing a superabsorbent polymer as an absorbent, and by using two or more types of superabsorbent polymers with different absorption capacities and liquid permeation rates arranged side by side without mixing them as the superabsorbent polymers, a flow path for body fluids is secured even after the body fluids are absorbed, and therefore it is possible to obtain an absorbent body and an absorbent article comprising said absorbent body that have excellent absorption properties and comfort, and that do not experience a decrease in absorption speed, particularly during repeated absorption, and that are excellent in diffusing body fluids. The present invention has been completed. The present invention relates to the following absorbent body and absorbent article comprising said absorbent body.

(1) An absorbent body for an absorbent article that does not contain flap pulp,
The present invention includes a multi-layer hydrophilic sheet and a highly absorbent sheet enclosed between the multi-layer hydrophilic sheet,
The highly absorbent sheet contains a highly absorbent polymer bonded to the hydrophilic sheet,
The superabsorbent polymer contains at least two or more types of superabsorbent polymers having different absorption capacities and liquid permeation rates,
The superabsorbent polymers having different absorption capacities and liquid permeation rates are arranged adjacent to each other in the absorbent body.
(2) The absorbent body according to (1) above, wherein the superabsorbent polymer comprises a highly absorbent type superabsorbent polymer having a relatively high absorption capacity and a relatively low liquid permeability rate, and a highly liquid permeable type superabsorbent polymer having a relatively low absorption capacity and a relatively high liquid permeability rate.
(3) The absorbent according to (2) above, wherein the highly absorbent polymer has an absorption capacity of 40 g/g or more and a liquid permeation rate of 10 ml/min or less.
(4) The absorbent according to (2) or (3) above, wherein the highly liquid-permeable superabsorbent polymer has an absorption capacity of less than 40 g/g and a liquid-permeability rate of 30 ml/min or more.
(5) The absorbent according to any one of (2) to (4) above, wherein the highly absorbent type superabsorbent polymer has an absorption capacity of 1.2 times or more compared to the highly liquid-permeable type superabsorbent polymer.
(6) The absorbent according to any one of (2) to (5) above, wherein the highly liquid-permeable superabsorbent polymer has a liquid permeation rate that is at least 5 times that of the highly absorbent polymer of the high absorption type.
(7) Any of the absorbents according to (2) to (6) above, having a gap between an area where the highly absorbent type superabsorbent polymer exists and an area where the highly liquid permeable type superabsorbent polymer exists, and the width dimension of the gap is 1 mm or more and 20 mm or less.
(8) An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed therebetween,
The absorbent article is any one of the absorbents described above in (1) to (7).

The present invention provides an absorbent body that does not lose its absorption rate when repeatedly absorbing body fluids, has excellent body fluid diffusion properties, and has good absorbency and comfort when worn, and an absorbent article that includes the absorbent body.

1 is a plan view illustrating a schematic configuration of an absorbent article according to a first embodiment of the present invention. 2 is a schematic cross-sectional view in the width direction taken along the X ₁ -X ₁ cutting line in FIG. 1. FIG. 4 is a cross-sectional view illustrating a schematic configuration of an absorbent article according to a second embodiment of the present invention.

In this specification, wearing an absorbent article refers to the state in which the absorbent article is attached to the body, regardless of whether it has absorbed bodily fluids or not. The longitudinal direction of the absorbent article is the direction that spans the front and back of the body via the wearer's crotch when the absorbent article is worn on the body, the width direction is the direction perpendicular to the longitudinal direction, and the thickness direction is the direction in which each component is layered. The skin side is the surface that contacts the wearer's skin and faces the skin when the absorbent article is worn, and the non-skin side is the surface that contacts the wearer's clothing and faces the clothing when the absorbent article is worn. Body fluids refer to liquids discharged from the body to the outside, such as urine, blood, and water in loose stools.

<Absorbent Articles>
1 and 2 are a schematic plan view of the absorbent article 1 according to the first embodiment as viewed from the top sheet 10 side and a schematic cross-sectional view in the width direction. Note that Fig. 1, Fig. 2, and Fig. 3 described later do not specify the shape or dimensions of each component of the absorbent articles 1 and 2. In Fig. 2 and other figures, each component such as the top sheet 10, the back sheet 11, and the absorbent body 14 is shown to be in close contact with each other, but this is not limited thereto, and at least one gap may exist between each component.

The absorbent article 1 can be used as various absorbent articles for babies or adults, such as light incontinence pads, urine absorption pads, pants-type paper diapers, tape-fastened paper diapers, etc. Also, various paper diapers as outerwear may be combined with the absorbent article 1 as innerwear. The longitudinal and width dimensions of the absorbent article 1 are not particularly limited, but are, for example, in the ranges of 100 mm to 800 mm and 50 mm to 500 mm, respectively. By setting the dimensions of the absorbent article 1 within the above ranges, the various absorbent articles mentioned above can be easily produced.

As shown in Figs. 1 and 2, the absorbent article 1 of this embodiment comprises a liquid-permeable top sheet 10 that is positioned relatively closer to the skin when worn, a liquid-impermeable back sheet 11 that is positioned opposite the top sheet 10 and is positioned relatively closer to the skin when worn, an absorbent body 14 that is positioned between the top sheet 10 and the back sheet 11 and does not contain flap pulp, and a pair of three-dimensional gathers 16 provided around both ends in the width direction of the skin-side surface of the top sheet 10. Leg gathers, waist gathers, side flaps, etc. can be provided as appropriate depending on the application and type of the absorbent article 1.

The absorbent body 14 of this embodiment, which does not contain flap pulp, includes two hydrophilic sheets 12 and 13 and a highly absorbent sheet 15 enclosed between them, and the highly absorbent sheet 15 includes at least two types of highly absorbent polymers with different absorption capacities and liquid permeation rates. The absorbent body 14 is sandwiched between the top sheet 10 and the back sheet 11, and absorbs and retains body fluids such as urine through the top sheet 10 in the absorbent body 14. The absorbent body 14 will be described in detail later.

According to this embodiment, at least two or more types of superabsorbent polymers with different absorption capacities and liquid permeability rates (for example, a highly absorbent type superabsorbent polymer and a highly liquid permeable type superabsorbent polymer) are used as the superabsorbent polymer contained in the superabsorbent sheet 15, and these superabsorbent polymers with different properties are not mixed, but are arranged in layers adjacent to each other, thereby maintaining a high level of body fluid absorption while preventing a decrease in body fluid diffusion even after body fluid absorption, and the absorption rate does not decrease especially during repeated absorption, and the entire absorbent body 14 can absorb and retain body fluids, significantly reducing liquid return, resulting in an absorbent body with good absorbency and wearing comfort and an absorbent article equipped with the absorbent body.

Below, each sheet-like or plate-like component will be described in more detail in the order of the top sheet 10, absorbent body 14, back sheet 11, and three-dimensional gathers 16. Note that the three-dimensional shape of each component is not limited to a sheet or plate shape.

(Top sheet)
The top sheet 10 is a liquid-permeable sheet-like substrate that quickly passes bodily fluids toward the absorbent 14, and is disposed opposite the back sheet 11 with the absorbent 14 sandwiched therebetween. Since the top sheet 10 may come into contact with the wearer's skin, a substrate that is soft to the touch and does not irritate the skin is preferable. Examples of the substrate include hydrophilic nonwoven fabrics, composite nonwoven fabrics that are laminates of the same or different hydrophilic nonwoven fabrics, open-type films such as open-type polyethylene films, and foamed films such as urethane foam. Examples of hydrophilic nonwoven fabrics include air-through nonwoven fabrics, thermal bond nonwoven fabrics, spunlace nonwoven fabrics, spunbond nonwoven fabrics, and the like, which contain one or more types of synthetic fibers made of synthetic resins such as polypropylene and polyethylene, regenerated fibers such as rayon, and natural fibers such as cotton. Among these, thermal bond nonwoven fabrics, spunbond nonwoven fabrics, and the like are preferable.

From the viewpoint of improving liquid permeability, the top sheet 10 may be embossed or perforated on the surface according to a known method. From the viewpoint of reducing irritation to the skin, the top sheet 10 may contain lotion, antioxidant, anti-inflammatory component, pH adjuster, antibacterial agent, moisturizer, etc. From the viewpoint of strength, processability, and liquid return amount, the basis weight of the top sheet 10 is, for example, in the range of 15 g/m ² or more and 200 g/m ² or less. There are no particular limitations on the shape of the top sheet 10, but it may have a shape that covers the absorbent body 14 and is necessary to guide bodily fluids to the absorbent body 14 without leakage.

<Absorbent>
The absorbent body 14 of this embodiment includes two hydrophilic sheets 12 and 13 and a highly absorbent sheet 15 enclosed between the two layers.

(hydrophilic sheet)
In this embodiment, the hydrophilic sheet 12 located on the top sheet 10 side has a flat sheet-like shape, and the hydrophilic sheet 13 located on the back sheet 11 side is formed to have a recess 23 recessed toward the back sheet 11 side at its center and capable of storing the super absorbent sheet 15, and flanges 24 extending from the opening of the recess 23 at its edge at approximately equal intervals in the width direction or horizontal direction. As described above, the super absorbent sheet 15 is stored in the recess 23 of the hydrophilic sheet 13. The edge of the back sheet side surface of the hydrophilic sheet 12 is overlapped with the top sheet 10 side surface of the flange 24 of the hydrophilic sheet 13, and the super absorbent sheet 15 is stored within the hydrophilic sheets 12, 13. This prevents the super absorbent sheet 15, which is made of a super absorbent polymer, from falling off from the absorbent body 14.

In this embodiment, two layers of hydrophilic sheets 12 and 13 are used, but this is not limited to this, and any hydrophilic sheet having three or more layers may be used. Also, in this embodiment, the hydrophilic sheet 12 is in the form of a flat sheet, and the hydrophilic sheet 13 is configured to have a recess 23 and a flange 24, but this is not limited to this, and a protrusion (protrusion protruding toward the top sheet 10) capable of storing the highly absorbent sheet 15 may be provided on the side of the hydrophilic sheet 12, or a protrusion and a recess may be provided on both the hydrophilic sheets 12 and 13, respectively, thereby storing the highly absorbent sheet 15.

As the hydrophilic sheets 12 and 13, any of those commonly used in this field can be used, for example, tissue paper, absorbent paper, hydrophilic nonwoven fabric, etc. Examples of hydrophilic nonwoven fabrics include thermal bonded nonwoven fabrics, spunbonded nonwoven fabrics, airlaid nonwoven fabrics, etc. Among these, from the viewpoint of availability, cost, etc., tissue paper, hydrophilic nonwoven fabrics, etc. are preferred, and hydrophilic nonwoven fabrics such as thermal bonded nonwoven fabrics and spunbonded nonwoven fabrics are more preferred. The basis weight of the hydrophilic sheets 12 and 13 is, for example, in the range of 7 g/m ² to 45 g/m ² or 13 g/m ² to 50 g/m ^2. The hydrophilic sheets 12 and 13 may be of the same type or different types.

(Highly absorbent sheet)
The superabsorbent sheet 15 enclosed between the multiple layers of the hydrophilic sheets 12 and 13 does not contain a flap valve and contains two or more types of superabsorbent polymers having different absorption capacities and liquid passing speeds as separate bodies. As shown in Figs. 1 and 2, the superabsorbent sheet 15 of this embodiment has three first superabsorbent polymer layers 20 (hereinafter also referred to as "first SAP layers 20") extending in the longitudinal direction and two second superabsorbent polymer layers 21 (hereinafter also referred to as "second SAP layers 21") extending in the longitudinal direction, which are alternately arranged in the width direction, with the first SAP layers 20 disposed on both outer sides in the width direction. The first SAP layer 20 and the second SAP layer 21 are adjacent to each other in the width direction. In this specification, "adjacent" also includes a form in which they are adjacent to each other with a gap therebetween.

In this embodiment, the first SAP layer 20 and the second SAP layer 21 are fixed to the non-skin side of the hydrophilic sheet 12 and/or the skin side of the hydrophilic sheet 13 by an adhesive or pressure-sensitive adhesive such as a hot melt adhesive. Examples of hot melt adhesives include synthetic rubber-based hot melt adhesives such as styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers, and olefin-based hot melt adhesives such as ethylene-vinyl acetate copolymers, each of which has a melting point of 100°C or higher and 180°C or lower.

Two or more types of superabsorbent polymers with different absorption capacities and liquid permeability rates include, for example, a combination of a highly absorbent type superabsorbent polymer with a relatively high absorption capacity and a relatively low liquid permeability rate (hereinafter simply referred to as "high absorption type") and a highly absorbent type superabsorbent polymer with a relatively low absorption capacity and a relatively high liquid permeability rate (hereinafter simply referred to as "high liquid permeability type"). Here, the absorption capacity is the absorption capacity (unit: g/g) after the superabsorbent polymer is immersed in a large excess of 0.9% by weight sodium chloride aqueous solution for 30 minutes under no pressure to allow it to freely expand, and then dehydrated at 150 G using a centrifuge. The liquid permeability rate is the liquid permeability rate (unit: ml/min) of a 0.9% by weight sodium chloride aqueous solution passing through the gel of the superabsorbent polymer that has been previously swollen in a large excess of 0.9% by weight sodium chloride aqueous solution under a pressure of 0.3 psi. More detailed methods for measuring the liquid permeation rate of SAP are described, for example, in paragraph 0037 of JP 2017-70497 A and paragraphs 0008 and 0009 of JP 2003-235889 A.

For example, an embodiment may be mentioned in which the highly absorbent type is contained in the first SAP layer 20 and the highly liquid permeable type is contained in the second SAP layer 21. In this embodiment, the first SAP layer 20 has the function of absorbing bodily fluids, and the second SAP layer 21 has the function of diffusing bodily fluids into the highly absorbent sheet 15. Therefore, blocking of the bodily fluid flow path due to gel blocking or the like is unlikely to occur, and even if bodily fluids are repeatedly absorbed, the diffusibility of the bodily fluids in the highly absorbent sheet 15 does not decrease, making it possible to utilize the entire highly absorbent type contained in the first SAP layer 20.

The highly absorbent type may, for example, have an absorption capacity of 40 g/g or more and a liquid passage rate of 10 ml/min or less. By using a highly absorbent polymer with a relatively high absorption capacity and a relatively low liquid passage rate as the highly absorbent type, the highly absorbent sheet 15 and the absorbent body 14 have excellent bodily fluid absorption capacity and can sufficiently absorb bodily fluids several times. The highly absorbent type may, for example, have an absorption capacity of less than 40 g/g and a liquid passage rate of 30 ml/min or more. By using a highly absorbent polymer with a relatively low absorption capacity and a relatively high liquid passage rate as the highly absorbent type, the bodily fluid flow path in the highly absorbent sheet 15 and the absorbent body 14 is secured until the end of use of the absorbent article 1, and bodily fluids can be efficiently absorbed and retained at a high absorption rate.

In another embodiment, the absorption capacity of the high-absorption type is 1.2 times or more that of the high-permeability type, and/or the permeability rate of the high-permeability type is 5 times or more that of the high-absorption type. According to this embodiment, the functions of the first SAP layer 20 to absorb and retain bodily fluids and the second SAP layer 21 to maintain a high level of bodily fluid diffusibility and act as a flow path for bodily fluids are more clearly defined, further improving the absorption performance of the absorbent 14, and in particular the initial absorption rate can be maintained even during repeated absorption.

The form of the first SAP layer 20 and the second SAP layer 21 is not particularly limited, and any known form can be adopted except that they contain a specified SAP, such as a form containing absorbent fibers and a specified SAP, or more specifically, a laminated mat formed by mixing SAP particles into absorbent fibers.

In this embodiment, three layers of the first SAP layer 20 and two layers of the second SAP layer 21 are alternately arranged in the width direction, but this is not limited thereto, and (n+1) layers of the first SAP layer 20 and n layers of the second SAP layer 21 can be alternately arranged. In addition, examples include a form in which a strip-shaped first SAP layer extending in the width direction and a strip-shaped second SAP layer extending in the width direction are alternately arranged in the longitudinal direction, a form in which a strip-shaped first SAP layer extending in one direction and a strip-shaped second SAP layer extending in one direction are alternately arranged in the diagonal direction, a form in which strip-shaped first and second SAP layers are alternately arranged in concentric circles, and a form in which first and second SAP layers are alternately arranged in a checkerboard pattern.

The superabsorbent polymer (hereinafter also simply referred to as "SAP") used in the superabsorbent sheet 15 is not particularly limited as long as it can absorb body fluids and prevent backflow, and examples thereof include polyacrylates, polyaspartates, (starch-acrylic acid) graft copolymers, (acrylic acid-vinyl alcohol) copolymers, (isobutylene-maleic anhydride) copolymers, and saponified products thereof. Among these, polyacrylates are preferred from the viewpoint of the absorption amount per weight, and sodium polyacrylate is more preferred. One type of SAP can be used alone, or two or more types can be used in combination. Various types of SAPs are commercially available that have different absorption capacities and liquid permeation rates due to differences in the manufacturing process, even if they are the same substance. Therefore, from various SAPs, a high absorption type with a relatively high absorption capacity and a relatively low liquid permeation rate and a high liquid permeation type with a relatively low absorption capacity and a relatively high liquid permeation rate can be appropriately selected and used. From the viewpoints of absorption performance and feel, the basis weight of the SAP in the super absorbent sheet 15 is, for example, in the range of 10 g/ ^m2 to 500 g/ ^m2 for both the first SAP layer 20 and the second SAP layer 21. The SAP content in the super absorbent sheet 15 is, for example, in the range of 15 mass % to 50 mass % of the total amount of the absorbent body 15.

In addition, when a powdered form of the superabsorbent polymer is used, the particle size is not particularly limited and can be selected from a wide range, for example, from 50 μm to 600 μm or from 100 μm to 500 μm. By using a powder in this range, the basic performance of absorbing body fluids can be improved and the rough feel caused by the hardening of the first SAP layer 20 can be reduced. If the particle size is less than 50 μm, the fluidity of the superabsorbent polymer as a powder tends to decrease and the absorption performance of body fluids tends to decrease, and if the particle size exceeds 600 μm, the absorbent article 1 tends to feel rough when worn and tends to feel rough after absorbing body fluids. A fibrous form of the superabsorbent polymer can also be used.

Figure 3 is a widthwise cross-sectional view of an absorbent article 2 including an absorbent body 14A of another embodiment. The absorbent article 2 has the same configuration as the absorbent article 1, except that it has an absorbent body 14A instead of the absorbent body 14. The absorbent body 14A has the same configuration as the absorbent body 14, except that it has a highly absorbent sheet 15A instead of the highly absorbent sheet 15.

The highly absorbent sheet 15A has three longitudinally extending first superabsorbent polymer layers 20A (hereinafter also referred to as "first SAP layers 20A") and two longitudinally extending second superabsorbent polymer layers 21A (hereinafter also referred to as "second SAP layers 21A") arranged alternately in the width direction, with the first SAP layers 20A arranged on both outer sides in the width direction, and a gap 25 being provided between adjacent first and second SAP layers 20A and 21A. Here again, for example, an embodiment may be used in which the first SAP layer 20A contains a highly absorbent type and the second SAP layer 21A contains a highly liquid permeable type.

By providing the gap 25, even after absorbing body fluid once or twice, a flow path for body fluid is secured, and body fluid can be absorbed multiple times. In this embodiment, the absorbency of the highly liquid-permeable type contained in the second SAP layer 21A may be increased to a degree not higher than the absorbency of the highly absorbent type contained in the first SAP layer 20A, so that body fluid can be absorbed within the second SAP layer 21A. The width dimension of the gap 25 is not particularly limited, but is, for example, in the range of 1 mm or more and 20 mm or less. If the width of the gap 25 is less than 1 mm, the effect of providing the gap 25 tends not to be fully realized. If the width of the gap 25 exceeds 20 mm, the strength of the absorbent body 14A as a whole decreases, making it difficult to stably absorb body fluid, and leakage, liquid backflow, etc. tend to occur.

(Back seat)
The back sheet 11 may be formed using a liquid-impermeable substrate that prevents the body fluid held by the absorbent 14 from wetting clothing, and is formed from a material such as a resin film or a composite sheet in which a resin film and a nonwoven fabric are laminated. The nonwoven fabric used in the composite sheet is not particularly limited in its manufacturing method, and examples thereof include spunbond nonwoven fabric, meltblown nonwoven fabric, composite nonwoven fabric in which a spunbond nonwoven fabric/meltblown nonwoven fabric, a spunbond nonwoven fabric/meltblown nonwoven fabric/spunbond nonwoven fabric are laminated, and composite materials thereof. Examples of the resin film include polyester, polyvinyl alcohol, polyethylene, polypropylene, composite films of polyethylene and polypropylene, etc. Among these, breathable and non-breathable liquid-impermeable plastic films are preferred.

From the viewpoint of strength and processability, the basis weight of the back sheet 11 is, for example, in the range of 15 g/m ² or more and 40 g/m ² or less. In addition, in order to prevent stuffiness during wearing, it is preferable that the back sheet 11 has breathability. In order to impart breathability to the back sheet 11, for example, a filler may be blended into the resin film of the base material, or the back sheet 11 may be embossed for perforation. In addition, examples of the filler include calcium carbonate. The blending method can be a known method without any restrictions. For example, a resin film having breathability can be obtained by kneading a filler into a synthetic resin, forming the resulting kneaded product into a film or sheet, and removing the filler from the resulting film or sheet.

(3D gathers)
As shown in FIG. 1, the absorbent article 1 is provided with three-dimensional gathers 16 along the longitudinal direction of the absorbent article 1 in order to prevent side leakage of bodily fluids excreted by the wearer. The three-dimensional gathers 16 include a sheet 16b and an elastically stretchable member 16a arranged along the longitudinal direction at the other end of the sheet 16b. In this embodiment, the sheet 16b has one widthwise end fixed to the vicinity of both widthwise ends of the skin side of the back sheet 11, a widthwise intermediate portion fixed to the vicinity of both widthwise ends of the skin side of the top sheet 10, and the other widthwise end being a free end. The fixing position of one widthwise end of the sheet 16b may be the non-skin side of the back sheet 11, the widthwise both ends of the skin side of the top sheet 10, the widthwise both ends of the bag of the top sheet 10 and the back sheet 11 that contains the absorbent 14, or the like. In addition, by arranging the elastically stretchable member 16a, the free end of the sheet 16b is given an uprightness, and can be deformed to fit the body shape of the wearer.

Examples of substrates that can be used for the sheet 16b include water-repellent or liquid-impermeable nonwoven fabrics made of hydrophobic fibers, such as spunbond nonwoven fabrics, meltblown nonwoven fabrics, and three-layer composite nonwoven fabrics of spunbond/meltblown/spunbond. Examples of the elastic stretch member 16a include polyurethane threads, strip-shaped polyurethane films, and thread- or strip-shaped natural rubber.

<Method of manufacturing absorbent articles>
The absorbent article 1 can be manufactured, for example, by sandwiching the absorbent body 14 between the top sheet 10 and the back sheet 11, fixing a part or the entire periphery of each edge of the top sheet 10 and the back sheet 11 using a hot melt adhesive, heat embossing, ultrasonic embossing, high frequency embossing, or the like, and further providing three-dimensional gathers 16 at predetermined positions as necessary. If the absorbent article 1 is a urine absorption pad or a light incontinence pad, it may be individually packaged in a package and then folded in thirds in the longitudinal direction. Leg gathers, waist gathers, side flaps, and the like may be provided as necessary.

The present invention has been described above using an embodiment, but it goes without saying that the technical scope of the present invention is not limited to the scope of the invention described in the above embodiment, and it is clear to those skilled in the art that various modifications and improvements can be made to the above embodiment. Furthermore, it is clear from the description of the claims that forms incorporating such modifications or improvements can also be included in the technical scope of the present invention.

The following examples and comparative examples will explain one embodiment of the present invention in more detail.

Example 1
An air-through nonwoven fabric (basis weight 20 g/m ² ) was used as the top sheet, an air-through nonwoven fabric (basis weight 20 g/m ² ) was used as the hydrophilic sheet, and a breathable polyethylene film (basis weight 35 g/m ² ) was used as the back sheet, and a highly absorbent SAP with an absorption capacity of 42 g/g and a liquid passage rate of 1 ml/min and a highly liquid-permeable SAP with an absorption capacity of 33 g/g and a liquid passage rate of 63 ml/min were used in the proportions shown in Table 1 to produce an absorbent article of Example 1 having a product length of 480 mm and a product width of 200 mm, as shown in Figures 1 and 2. The highly absorbent type had a first SAP layer (length 300 mm x width 20 mm) in three places, and the highly liquid-permeable type had a second SAP layer (length 300 mm x width 20 mm) in two places.

The absorption capacity of the SAP was measured by the method described above. The liquid permeation rate of the SAP was measured as follows.
(Liquid passing speed)
0.32±0.005 g of SAP was weighed and placed in a 100 mL beaker, and then a large excess amount (e.g., 5 times or more the saturated absorption amount of SAP) of physiological saline (0.9 mass% sodium chloride aqueous solution) was added and left for 30 minutes to prepare a measurement sample. The obtained measurement sample was placed in a filtration cylindrical tube equipped with a wire mesh (opening 150 μm, product name: Biocolumn Sintered Stainless Filter 30 SUS, Sansho Co., Ltd.) and a capillary tube (inner diameter 4 mm, length 8 cm) with a cock (inner diameter 2 mm) with the cock closed. Next, a cylindrical rod with a diameter of 2 mm and a wire mesh with a diameter of 25 mm at its tip was inserted into the filtration cylindrical tube so that the wire mesh and the measurement sample were in contact with each other, and a weight was placed on the measurement sample to apply a load of 2.0 kPa. After leaving it in this state for 1 minute, the cock was opened and the time T1 (seconds) until 20 mL of the measurement sample passed through the wire mesh was measured. As a blank, normal saline was placed in the cylindrical filtration tube instead of the measurement sample, and the time T0 (seconds) required for 20 ml of the saline to pass through the wire mesh was measured under the same conditions as when measuring T1. Using the obtained times T1 (seconds) and T0 (seconds), and the following formula, the liquid passing rate under a pressure of 2.0 kPa was calculated.
Flow rate (ml/min) = 20 x 60/(T1-T0)
The measurement was performed five times (n=5), one value from each of the top and bottom was deleted, and the average value of the remaining three values was used as the measured value. The measurement was performed at 23±2°C and humidity of 50±5%, and the SAP was stored in the same environment for 24 hours or more before the measurement.

(Comparative Example 1)
An absorbent article of Comparative Example 1 was produced in the same manner as in Example 1, except that a highly absorbent sheet was formed consisting only of highly absorbent type SAP.

(Comparative Example 2)
An absorbent article of Comparative Example 2 was produced in the same manner as in Example 1, except that a highly absorbent sheet was formed consisting only of highly liquid-permeable SAP.

(Comparative Example 3)
An absorbent article of Comparative Example 3 was produced in the same manner as in Example 1, except that the highly absorbent sheet was made of a mixture of highly absorbent and highly liquid-permeable SAP.

The following performance tests were carried out on the absorbent articles obtained in Example 1 and Comparative Examples 1 to 3. The results are shown in Table 1.
(Absorption rate)
For each of the absorbent articles of Example 1 and Comparative Examples 1 to 3, 150 ml of saline was poured into a jig having a bottom surface of 140 mm×100 mm, an outer diameter of 40 mm, an inner diameter of 35 mm, and a weight of 1,400 g, and the time (seconds) until each absorbent article absorbed the saline was measured. Pouring of water was repeated three times at three-minute intervals, and the time (seconds) until absorption was measured.
(Liquid return)
Ten minutes after completing the three absorption rate measurements, a 55 mm diameter filter paper was placed on the surface of each absorbent article, and a load of 35 gf/ ^cm2 was applied from above the filter paper and left for one minute. The amount of moisture that flowed back and was absorbed by the filter paper was then measured as the increase in the weight of the filter paper.
(Diffusion Length)
After the absorption rate was measured three times, the maximum length (mm) of the part of the surface of each absorbent article that had absorbed the physiological saline solution was measured.

1.2 Absorbent article 10 Top sheet 11 Back sheet 12, 13 Hydrophilic sheet 14, 17 Absorbent body 15, 15A Highly absorbent sheet 16 Three-dimensional gather 20 First highly absorbent polymer layer 21 Second highly absorbent polymer layer 23 Recess 24 Flange 25 Gap

Claims (7)

An absorbent body for an absorbent article that does not contain flap pulp,
The hydrophilic sheet is located on the top sheet side, a hydrophilic sheet is located on the back sheet side, and a highly absorbent sheet is enclosed between the hydrophilic sheet located on the top sheet side and the hydrophilic sheet located on the back sheet side,
The highly absorbent sheet contains a highly absorbent polymer layer bonded to at least one of a hydrophilic sheet located on the top sheet side and a hydrophilic sheet located on the back sheet side,
the superabsorbent polymer layer includes a first superabsorbent polymer layer and a second superabsorbent polymer layer disposed adjacent to the first superabsorbent polymer layer;
the first superabsorbent polymer layer contains a highly absorbent type superabsorbent polymer having a relatively high absorption capacity and a relatively low liquid permeation rate, and the second superabsorbent polymer layer contains a highly liquid permeable type superabsorbent polymer having a relatively low absorption capacity and a relatively high liquid permeation rate ,
The superabsorbent polymer layers are arranged on both outer sides in the width direction of the absorbent body. 2. The absorbent body according to claim 1 , wherein the highly absorbent superabsorbent polymer has an absorption capacity of 40 g/g or more and a liquid permeation rate of 10 ml/min or less. 3. The absorbent body according to claim 1, wherein the highly liquid-permeable superabsorbent polymer has an absorption capacity of less than 40 g/g and a liquid-permeability rate of 30 ml/min or more. The absorbent according to any one of claims 1 to 3 , wherein the highly absorbent type superabsorbent polymer has an absorption capacity of 1.2 times or more that of the highly liquid permeable type superabsorbent polymer. The absorbent body according to any one of claims 1 to 4 , wherein the highly liquid-permeable superabsorbent polymer has a liquid permeation rate that is at least five times that of the highly absorbent polymer of the high absorption type. The absorbent body according to any one of claims 1 to 5 , wherein a gap having a width dimension of 1 mm or more and 20 mm or less is provided between adjacent first and second superabsorbent polymer layers. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed therebetween,
The absorbent article, wherein the absorbent body is the absorbent body according to any one of claims 1 to 6 .